INSTALLATION
INSTRUCTIONS
E 2009 Lennox Industries Inc.
Dallas, Texas, USA
G61MP SERIES UNITS
GAS UNITS
506406−01
08/2009
Litho U.S.A.
Supersedes 505,124M
Table of Contents
Unit Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
G61MP Parts Identification . . . . . . . . . . . . . . . . . . . . . . 3
Shipping and Packing List . . . . . . . . . . . . . . . . . . . . . . 4
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Use of Furnace as Construction Heater . . . . . . . . . . . 5
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Combustion, Dilution & Ventilation Air . . . . . . . . . . . . 6
Installation − Setting Equipment . . . . . . . . . . . . . . . . . . 8
Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Duct System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Pipe & Fittings Specifications . . . . . . . . . . . . . . . . . . . . 16
Vent Piping Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . 18
Joint Cementing Procedure . . . . . . . . . . . . . . . . . . . . . 20
Venting Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Integrated Control Board . . . . . . . . . . . . . . . . . . . . . . . 42
Unit Start−Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Gas Pressure Adjustment . . . . . . . . . . . . . . . . . . . . . . 44
High Altitude Information . . . . . . . . . . . . . . . . . . . . . . . 45
Other Unit Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . 46
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Ignition Control Board Diagnostic Codes . . . . . . . . . . 56
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Repair Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Vent Pipe Sizing Worksheet . . . . . . . . . . . . . . . . . . . . . 63
Start−Up & Performance Check List . . . . . . . . . . . . . . 63
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
WARNING
FIRE OR EXPLOSION HAZARD.
Failure to follow safety warnings exact-
ly could result in serious injury, death,
or property damage.
WHAT TO DO IF YOU SMELL GAS:
Do not store or use gasoline or other
D Do not try to light any appliance.
flammable vapors and liquids in the
vicinity of this or any other ap-
pliance.
D Do not touch any electrical switch; do not
use any phone in your building.
D Leave the building immediately.
D Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.
Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.
D If you cannot reach your gas supplier, call
the fire department.
08/09
506406−01
Page 1
*2P0809*
*P506406-01*
Download from Www.Somanuals.com. All Manuals Search And Download.
G61MP Parts Arrangement
G61MP PARTS IDENTIFICATION
TOP CAP
DuralokPlusTM
HEAT EXCHANGER
ASSEMBLY
CABINET
BURNER BOX
ASSEMBLY
GAS VALVE
AND MANIFOLD
FLUE
COLLAR
COMBUSTION
AIR PRESSURE
PROVE SWITCHES*
WARM HEADER
(COLLECTOR)
BOX
COMBUSTION AIR
INDUCER
CONDENSER COIL
BURNER
ACCESS
PANEL
PRIMARY LIMIT
COLD HEADER
(COLLECTOR)
BOX
BLOWER
ACCESS
DOOR
DOOR
INTERLOCK
SWITCH
SECONDARY
LIMITS (2)
*G61MP−090 shown.
G61MP−045 and −070
are equipped with
two switches.
BLOWER
ASSEMBLY
SIGHT
GLASS
CONTROL BOX
FIGURE 1
Page 3
Download from Www.Somanuals.com. All Manuals Search And Download.
NOTE
−
G61MP−48C−110, G61MP−60C−110 and
G61MP Gas Furnace
G61MP−60C−111 units also include a 2" diameter PVC
street elbow, which is shipped on the blower deck in the
heating compartment. G61MP−60D−135 units are shipped
with a 3" to 2" PVC reducing elbow.
The G61MP category IV gas furnace is shipped ready for
installation in the upflow, downflow, horizontal left air dis-
charge or horizontal right air discharge position. The fur-
nace is shipped with the bottom panel in place. The bot-
tom panel must be removed if the unit is to be installed in
upflow applications with bottom return air. The bottom
panel must also be removed and discarded in all downflow
or horizontal applications.
Canadian Installations Only − Replace the provided 2"
street elbow shipped with the G61MP−48C−110,
G61MP−60C−110 and G61MP−60C−111 units with 2" street
elbow Y0162. Replace the provided 3" X 2" reducing elbow
shipped with the G61MP−60D−135 units with 3" X 2" reduc-
ing elbow 40W22. Y0162 and 40W22 meet B149 vent re-
quirements.
The furnace is equipped for installation in natural gas ap-
plications. A conversion kit (ordered separately) is re-
quired for use in propane/LP gas applications.
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
The G61MP can be installed as either a Direct Vent or a
Non−Direct Vent gas central furnace.
The following items may also be ordered separately:
1 − Thermostat
NOTE − In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged outdoors. In
Non−Direct Vent installations, combustion air is taken from
indoors and flue gases are discharged outdoors. See figure
2 for applications involving roof termination.
1 − Propane/LP changeover kit
DANGER
Danger of explosion.
DIRECT VENT INSTALLATION
COMBUSTION
NON−DIRECT VENT
INSTALLATION
There are circumstances in which odorant used with
LP/propane gas can lose its scent. In case of a leak,
LP/propane gas will settle close to the floor and may
be difficult to smell. An LP/propane leak detector
should be installed in all LP applications.
EXHAUST
AIR INTAKE
OUTLET
EXHAUST
OUTLET
OUTSIDE OF
HOUSE
COMBUSTION
AIR INTAKE INSIDE
OF HOUSE
Safety Information
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a licensed professional installer (or
equivalent), service agency or the gas supplier.
G61MP
G61MP
CONDENSATE
DRAIN
CONDENSATE
DRAIN
FIGURE 2
CAUTION
Shipping and Packing List
As with any mechanical equipment, personal injury
can result from contact with sharp sheet metal
edges. Be careful when you handle this equipment.
Package 1 of 1 contains
1 − Assembled G61MP unit
1 − Bag assembly containing the following:
3 −Screws
Use only the type of gas approved for use with this furnace.
Refer to unit nameplate.
3 −Wire nuts
G61MP units are CSA International certified to ANSI
Z21.47 and CSA 2.3 standards.
1 −Snap bushing
1 −Snap plug
In the USA, installation of gas furnaces must conform with lo-
cal building codes. In the absence of local codes, units must
be installed according to the current National Fuel Gas Code
(ANSI-Z223.1/NFPA 54). The National Fuel Gas Code is
available from the following address:
1 − Wire tie
1 −Condensate trap
1 −Condensate trap cap
2 −2" diameter vent / intake plugs
1 −3" diameter cabinet plug (intake)
1 −2" diameter debris screen
1 −Logo sticker (for use in downflow applications)
American National Standards Institute, Inc.
11 West 42nd Street
New York, NY 10036
Page 4
Download from Www.Somanuals.com. All Manuals Search And Download.
In Canada, installation must conform with current National
Standard of Canada CSA-B149 Natural Gas and Propane
Installation Codes, local plumbing or waste water codes
and other applicable local codes.
When installed, this furnace must be electrically grounded
according to local codes. In addition, in the United States,
installation must conform with the current National Electric
Code, ANSI/NFPA No. 70. The National Electric Code
(ANSI/NFPA No. 70) is available from the following ad-
dress:
In order to ensure proper unit operation in non−direct vent
applications, combustion and ventilation air supply must be
provided according to the current National Fuel Gas Code
or CSA-B149 standard.
National Fire Protection Association
1 Battery March Park
Quincy, MA 02269
This furnace is CSA International certified for installation
clearances to combustible material as listed on the unit
bility and service clearances must take precedence over fire
protection clearances.
In Canada, all electrical wiring and grounding for the unit
must be installed according to the current regulations of the
Canadian Electrical Code Part I (CSA Standard C22.1)
and/or local codes.
NOTE − This furnace is designed for a minimum continu-
ous return air temperature of 60°F (16°C) or an intermit-
tent operation down to 55°F (13°C) dry bulb for cases
where a night setback thermostat is used. Return air tem-
perature must not exceed 85°F (29°C) dry bulb.
NOTE − For installation on combustible floors, the furnace
shall not be installed directly on carpeting, tile, or other
combustible material other than wood flooring.
For installation in a residential garage, the furnace must
be installed so that the burner(s) and the ignition source
are located no less than 18 inches (457 mm) above the
floor. The furnace must be located or protected to avoid
physical damage by vehicles. When a furnace is installed
in apublic garage, hangar, or other building that has a haz-
ardous atmosphere, the furnace must be installed accord-
ing to recommended good practice requirements and cur-
rent National Fuel Gas Code or CSA B149 standard.
The G61MP furnace may be installed in alcoves, closets,
attics, basements, garages, and utility rooms.
This furnace design has not been CSA certified for installa-
tion in mobile homes, recreational vehicles, or outdoors.
Never use an open flame to test for gas leaks. Check all
connections using a commercially available soap solution
made specifically for leak detection.
Use of Furnace as Construction Heater
NOTE − Furnace must be adjusted to obtain a temperature
rise within the range specified on the unit nameplate. Failure
to do so may cause erratic limit operation.
Lennox does not recommend the use of G61MP units as a
construction heater during any phase of construction. Very
low return air temperatures, harmful vapors and operation
of the unit with clogged or misplaced filters will damage the
unit.
This G61MP furnace may be used as a high−static unit
heater. The G61MP may also be installed in an aircraft han-
gar in accordance with the Standard for Aircraft Hangars
(ANSI/NFPA No. 408−1990).
G61MP units may be used for heating of buildings or struc-
tures under construction, if the following conditions are
met:
Installation in parking structures must be in accordance
with the Standard for Parking Structures (ANSI/NFPA No.
88A−1991). Installation in repair garages must be in accor-
dance with the Standard for Repair Garages (ANSI/NFPA
No. 88B−1991).
D The vent system must be permanently installed per
these installation instructions.
D A room thermostat must control the furnace. The use of
fixed jumpers that will provide continuous heating is not
allowed.
This G61MP furnace must be installed so that its electrical
components are protected from water.
D The return air duct must be provided and sealed to the
furnace.
When this furnace is used with cooling units, it shall be
installed in parallel with, or on the upstream side of, cooling
units to avoid condensation in the heating compartment.
With a parallel flow arrangement, a damper (or other means
to control the flow of air) must adequately prevent chilled air
from entering the furnace. If the damper is manually oper-
ated, it must be equipped to prevent operation of either the
heating or the cooling unit, unless it is in the full HEAT or
COOL setting.
D Return air temperature range between 60°F (16°C) and
80°F (27°C) must be maintained.
D Air filters must be installed in the system and must be
maintained during construction.
D Air filters must be replaced upon construction comple-
tion.
D The input rate and temperature rise must be set per the
furnace rating plate.
Page 5
Download from Www.Somanuals.com. All Manuals Search And Download.
D One hundred percent (100%) outdoor air must be pro-
vided for combustion air requirements during construc-
tion. Temporary ducting may supply outdoor air to the
furnace. Do not connect duct directly to the furnace.
Size the temporary duct following these instructions in
section for Combustion, Dilution and Ventilation Air in a
confined space with air from outside.
CAUTION
G61MP unit should not be installed in areas normally
subject to freezing temperatures.
Combustion, Dilution & Ventilation Air
D The furnace heat exchanger, components, duct system,
air filters and evaporator coils must be thoroughly
cleaned following final construction clean−up.
If the G61MP is installed as a Non−Direct Vent Fur-
nace, follow the guidelines in this section.
NOTE − In Non−Direct Vent installations, combustion air
is taken from indoors and flue gases are discharged out−
doors.
D All furnace operating conditions (including ignition, in-
put rate, temperature rise and venting) must be verified
according to these installation instructions.
General
WARNING
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rust-
ing and premature heat exchanger failure. Excessive
exposure to contaminated combustion air will result
in safety and performance related problems. Avoid
exposure to the following substances in the com-
bustion air supply:
In addition to the requirements outlined previously, the fol-
lowing general recommendations must be considered
when installing a G61MP furnace:
• Place the furnace as close to the center of the air dis-
tribution system as possible. The furnace should also be
located close to the chimney or vent termination point.
Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine base swimming pool chemicals
Water softening chemicals
De−icing salts or chemicals
• When the furnace is installed in non−direct vent applica-
tions, do not install the furnace where drafts might blow
directly into it. This could cause improper combustion
and unsafe operation.
Carbon tetrachloride
Halogen type refrigerants
Cleaning solvents (such as perchloroethylene)
Printing inks, paint removers, varnishes, etc.
Hydrochloric acid
Cements and glues
Antistatic fabric softeners for clothes dryers
Masonry acid washing materials
• When the furnace is installed in non−direct vent applica-
tions, do not block the furnace combustion air opening
with clothing, boxes, doors, etc. Air is needed for proper
combustion and safe unit operation.
• When the furnace is installed in an attic or other insu-
lated space, keep insulation away from the furnace.
In the past, there was no problem in bringing in sufficient
outdoor air for combustion. Infiltration provided all the air
that was needed. In today’s homes, tight construction
practices make it necessary to bring in air from outside
for combustion. Take into account that exhaust fans, ap-
pliance vents, chimneys, and fireplaces force additional
air that could be used for combustion out of the house.
Unless outside air is brought into the house for combus-
tion, negative pressure (outside pressure is greater than
inside pressure) will build to the point that a downdraft
can occur in the furnace vent pipe or chimney. As a result,
combustion gases enter the living space creating a po-
tentially dangerous situation.
• When the furnace is installed in an unconditioned
space, consider provisions required to prevent freezing
of condensate drain system.
WARNING
Product contains fiberglass wool.
Disturbing the insulation in this product during
installation, maintenance, or repair will expose you
to fiberglass wool. Breathing this may cause lung
cancer. (Fiberglass wool is known to the State of Cal-
ifornia to cause cancer.)
Fiberglass wool may also cause respiratory, skin,
and eye irritation.
In the absence of local codes concerning air for combus−
tion and ventilation, use the guidelines and procedures in
this section to install G61MP furnaces to ensure efficient
and safe operation. You must consider combustion air
needs and requirements for exhaust vents and gas pip-
ing. A portion of this information has been reprinted with
permission from the National Fuel Gas Code (ANSI−
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact your
supervisor.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379−9900
Page 6
Download from Www.Somanuals.com. All Manuals Search And Download.
Z223.1/NFPA 54). This reprinted material is not the com-
plete and official position of the ANSI on the referenced
subject, which is represented only by the standard in its
entirety.
which are sealed to the furnace casing and which terminate
outside the space containing the furnace. This is especially
important when the furnace is mounted on a platform in a
confined space such as a closet or small equipment room.
Even a small leak around the base of the unit at the platform
or at the return air duct connection can cause a potentially
dangerous negative pressure condition. Air for combustion
and ventilation can be brought into the confined space ei-
ther from inside the building or from outside.
In Canada, refer to the standard CSA B149 installation
codes.
CAUTION
Do not install the furnace in a corrosive or contami-
nated atmosphere. Meet all combustion and ventila-
tion air requirements, as well as all local codes.
Air from Inside
If the confined space that houses the furnace adjoins a
space categorized as unconfined, air can be brought in by
providing two permanent openings between the two
spaces. Each opening must have a minimum free area of 1
All gas-fired appliances require air for the combustion pro-
cess. If sufficient combustion air is not available, the fur-
nace or other appliance will operate inefficiently and un-
safely. Enough air must be provided to meet the needs of all
fuel−burning appliances and appliances such as exhaust
fans which force air out of the house. When fireplaces, ex-
haust fans, or clothes dryers are used at the same time as
the furnace, much more air is required to ensure proper
combustion and to prevent a downdraft. Insufficient air
causes incomplete combustion which can result in carbon
monoxide.
2
square inch (645 mm ) per 1,000 Btu (.29 kW) per hour of
total input rating of all gas−fired equipment in the confined
space. Each opening must be at least 100 square inches
2
(64516 mm ). One opening shall be within 12 inches (305
mm) of the top of the enclosure and one opening within 12
EQUIPMENT IN CONFINED SPACE − ALL AIR FROM INSIDE
ROOF TERMINATED
EXHAUST PIPE
In addition to providing combustion air, fresh outdoor air di-
lutes contaminants in the indoor air. These contaminants
may include bleaches, adhesives, detergents, solvents
and other contaminants which can corrode furnace compo-
nents.
The requirements for providing air for combustion and ven-
tilation depend largely on whether the furnace is installed in
an unconfined or a confined space.
OPENINGS
(To Adjacent
SIDE WALL
Unconfined
TERMINATED EX-
Space)
HAUST PIPE (ALTER-
NATE LOCATION)
G61MP
Unconfined Space
An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cubic
NOTE − Each opening shall have a free area of at least one square
2
3
feet (1.42 m ) per 1,000 Btu (.29 kW) per hour of the com-
inch per 1,000 Btu (645mm per .29kW) per hour of the total input
rating of all equipment in the enclosure, but not less than 100 square
2).
inches (64516mm.
bined input rating of all appliances installed in that space.
This space also includes adjacent rooms which are not
separated by a door. Though an area may appear to be un-
confined, it might be necessary to bring in outdoor air for
combustion if the structure does not provide enough air by
infiltration. If the furnace is located in a building of tight
construction with weather stripping and caulking around
the windows and doors, follow the procedures in the air
from outside section.
FIGURE 3
Air from Outside
If air from outside is brought in for combustion and ventila-
tion, the confined space shall be provided with two perma-
nent openings. One opening shall be within 12" (305mm)
of the top of the enclosure and one within 12" (305mm) of
the bottom. These openings must communicate directly
or by ducts with the outdoors or spaces (crawl or attic) that
freely communicate with the outdoors or indirectly
through vertical ducts. Each opening shall have a mini-
Confined Space
A confined space is an area with a volume less than 50 cubic
3
2
mum free area of 1 square inch per 4,000 Btu (645mm
feet (1.42 m ) per 1,000 Btu (.29 kW) per hour of the com−
per 1.17kW) per hour of total input rating of all equipment
in the enclosure. When communicating with the outdoors
through horizontal ducts, each opening shall have a mini-
mum free area of 1 square inch per 2,000 Btu (645mm
per .59kW) per total input rating of all equipment in the en-
bined input rating of all appliances installed in that space. This
definition includes furnace closets or small equipment rooms.
When the furnace is installed so that supply ducts carry air
circulated by the furnace to areas outside the space con-
taining the furnace, the return air must be handled by ducts
2
Page 7
Download from Www.Somanuals.com. All Manuals Search And Download.
ing with the outdoors through horizontal ducts, each open-
ing shall have a minimum free area of 1 square inch (645
EQUIPMENT IN CONFINED SPACE − ALL AIR FROM OUTSIDE
(Inlet Air from Crawl Space and Outlet Air to Ventilated Attic)
VENTILATION LOUVERS
(Each end of attic)
2
mm ) per 2,000 Btu (.56 kW) per total input rating of all
ROOF TERMINATED
EXHAUST PIPE
When ducts are used, they shall be of the same cross−sec-
tional area as the free area of the openings to which they
connect. The minimum dimension of rectangular air ducts
shall be no less than 3 inches (75 mm). In calculating free
area, the blocking effect of louvers, grilles, or screens
must be considered. If the design and free area of protec-
tive covering is not known for calculating the size opening
required, it may be assumed that wood louvers will have
20 to 25 percent free area and metal louvers and grilles
will have 60 to 75 percent free area. Louvers and grilles
must be fixed in the open position or interlocked with the
equipment so that they are opened automatically during
equipment operation.
OUTLET
AIR
SIDE WALL
TERMINATED
EXHAUST PIPE
(ALTERNATE
LOCATION)
VENTILATION
LOUVERS
(For unheated
crawl space)
G61MP
INLET
AIR
NOTE−The inlet and outlet air openings shall each have a free area
2
of at least one square inch per 4,000 Btu (645mm per 1.17kW) per
hour of the total input rating of all equipment in the enclosure.
EQUIPMENT IN CONFINED SPACE −
ALL AIR FROM OUTSIDE
FIGURE 4
ROOF TERMINATED
EXHAUST PIPE
OUTLET AIR
EQUIPMENT IN CONFINED SPACE − ALL AIR FROM OUTSIDE
(All Air Through Ventilated Attic)
SIDE WALL
TERMINATED
EXHAUST PIPE
(ALTERNATE
LOCATION)
ROOF TERMINATED
EXHAUST PIPE
VENTILATION LOUVERS
(Each end of attic)
G61MP
INLET AIR
OUTLET
AIR
NOTE−Each air duct opening shall have a free area of at least one
2
square inch per 2,000 Btu (645mm per .59kW) per hour of the total
input rating of all equipment in the enclosure. If the equipment room
is located against an outside wall and the air openings communi-
cate directly with the outdoors, each opening shall have a free area
of at least 1 square inch per 4,000 Btu (645mm per 1.17kW) per
hour of the total input rating of all other equipment in the enclosure.
INLET AIR
(Ends 12" above
bottom)
SIDE WALL
TERMINATED
EXHAUST PIPE
(ALTERNATE
LOCATION)
2
G61MP
FIGURE 6
NOTE−The inlet and outlet air openings shall each have a free area of
2
at least one square inch per 4,000 Btu (645mm per 1.17kW) per hour
of the total input rating of all equipment in the enclosure.
Installation − Setting Equipment
WARNING
FIGURE 5
Do not install the furnace on its front or its back. Do
not connect the return air ducts to the back of the fur-
nace. Doing so will adversely affect the operation of
the safety control devices, which could result in per-
sonal injury or death.
If air from outside is brought in for combustion and ventila-
tion, the confined space must have two permanent open-
ings. One opening shall be within 12 inches (305 mm) of
the top of the enclosure and one opening within 12 inches
(305 mm) of the bottom. These openings must communi-
cate directly or by ducts with the outdoors or spaces (crawl
or attic) that freely communicate with the outdoors or indi-
rectly through vertical ducts. Each opening shall have a
Select a location that allows for the required clearances
that are listed on the unit nameplate. Also consider gas
supply connections, electrical supply, vent connection,
condensate trap and drain connections, and installation
and service clearances [24 inches (610 mm) at unit
front].
2
minimum free area of 1 square inch (645 mm ) per 4,000
Btu (1.17 kW) per hour of total input rating of all equipment
Page 8
Download from Www.Somanuals.com. All Manuals Search And Download.
SETTING EQUIPMENT
UPFLOW APPLICATION
DOWNFLOW APPLICATION
UNIT MUST BE LEVEL SIDE−TO−SIDE IN ALL APPLICATIONS.
AIR FLOW
HORIZONTAL APPLICATION
AIR FLOW
AIR FLOW
FRONT VIEW
FRONT VIEW
FRONT VIEW
AIR FLOW
UNIT
FRONT
UNIT
FRONT
UNIT
FRONT
1/2"
max.
AIR FLOW
END VIEW
1/2"
max.
1/2"
max.
UNIT SHOULD BE LEVEL FROM LEFT TO RIGHT BUT MAY BE
TILTED SLIGHTLY (MAX. 1/2") FROM BACK TO FRONT
TO AID IN THE DRAINING OF THE HEAT EXCHANGER.
SIDE VIEW
SIDE VIEW
FIGURE 7
The unit must be level from side to side. The unit may be
tilted slightly (maximum 1/2 in.) from back to front to aid
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or al-
NOTE − Units with 1/2 hp blower motors are equipped with
three flexible legs and one rigid leg. The rigid leg is
equipped with a shipping bolt and a flat white plastic wash-
er (rather than the rubber mounting grommet used with a
flexible mounting leg). The bolt and washer must be re-
moved before the furnace is placed into operation. Af-
ter the bolt and washer have been removed, the rigid leg
will not touch the blower housing.
WARNING
Improper installation of the furnace can result in per-
sonal injury or death. Combustion and flue products
must never be allowed to enter the return air system
or air in the living space. Use sheet metal screws and
joint tape to seal return air system to furnace.
In platform installations with furnace return, the fur-
nace should be sealed airtight to the return air ple-
num. A door must never be used as a portion of the
return air duct system. The base must provide a
stable support and an airtight seal to the furnace. Al-
low absolutely no sagging, cracks, gaps, etc.
For no reason should return and supply air duct sys-
tems ever be connected to or from other heating de-
vices such as a fireplace or stove, etc. Fire, explo-
sion, carbon monoxide poisoning, personal injury
and/or property damage could result.
WARNING
Blower access panel must be securely in place when
blower and burners are operating. Gas fumes, which
could contain carbon monoxide, can be drawn into
living space resulting in personal injury or death.
Page 9
Download from Www.Somanuals.com. All Manuals Search And Download.
Return Air −− Upflow Units
Upflow Applications
Return air can be brought in through the bottom or either
side of the furnace installed in an upflow application. If the
furnace is installed on a platform with bottom return, make
an airtight seal between the bottom of the furnace and the
platform to ensure that the furnace operates properly and
safely. The furnace is equipped with a removable bottom
panel to facilitate installation.
The G61MP gas furnace can be installed as shipped in
Installation Clearances
Top
Markings are provided on both sides of the furnace cabinet
for installations that require side return air. Cut the furnace
cabinet at the maximum dimensions shown on page 2.
Left Side
Right Side
NOTE − When air volumes over 1800 cfm (850 L/s) are
required with 60C or 60D models in an upflow applica-
tion, the following return air options are available:
Bottom (Floor)
1 − Return air from single side with transition which will
accommodate 20 x 25 x 1 in. (508 x 635 x 25 mm) air filter.
Top/Plenum
*Front
Back
1 in. (25 mm)
0
0
2 − Return air from single side with optional RAB Return
Air Base. See figure 9.
3 − Return air from bottom.
Sides
0†
0
4 − Return air from both sides.
Vent
5 − Return air from bottom and one side.
Refer to Engineering Handbook for additional information.
Floor
0‡
*Front clearance in alcove installation must be 24 in. (610 mm).
Maintain a minimum of 24 in. (610 mm) for front service access.
†Allow proper clearances to accommodate condensate trap and
vent pipe installation.
‡For installations on a combustible floor, do not install the furnace
directly on carpeting, tile or other combustible materials other
than wood flooring.
FIGURE 8
Page 10
Download from Www.Somanuals.com. All Manuals Search And Download.
Optional Return Air Base
(Upflow Applications Only −− For use with B, C and D cabinets only)
1
23 (584)
Overall
(Maximum)
4
(102)
1
Minimum
11 (279)
Maximum
14 (356)
14
(356)
1
2
22−7−16
(570)
Overall
1
Unit side return air
Opening
AIR FLOW
FURNACE
FRONT
(Maximum)
SIDE RETURN
AIR OPENINGS
(Either Side)
5−5/8
(143)
7−1/4 (184)
3/4
(19)
23 (584)
OPTIONAL RAB
RETURN AIR BASE
17−1/2 (446) RAB−B (98M60)
21 (533) RAB−C (98M58)
24−1/2 (622) RAB−D (98M59)
FRONT VIEW
7/8
(22)
27−5/8 (702)
SIDE VIEW
NOTE− Optional Side Return Air Filter Kits are not for use with RAB Return Air Base.
1
Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.
Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in.
(584 x 279 mm).
The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown.
Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return
air opening. The size of the opening must not extend beyond the markings on the furnace cabinet.
To minimize pressure drop, the largest opening height possible (up to 14 inches) is preferred.
2
NOTE− Optional Side Return Air Filter Kits are not for use with RAB Return Air Base.
FIGURE 9
G61MP applications which include side return air and
a condensate trap installed on the same side of the
cabinet require either a return air base or field−fabri-
cated transition to accommodate an optional IAQ ac-
cessory taller than 14.2".
Removing the Bottom Panel
Remove the two screws that secure the bottom cap to the
furnace. Pivot the bottom cap down to release the bottom
panel. Once the bottom panel has been removed, reinstall
Removing the Bottom Panel
Side Return Air
(with transition and filter)
20" X 25" X 1"
(508mm X635mm X 25mm)
Air Filter
Screw
Return
Air
Plenum
Bottom Cap
Bottom Panel
Transition
FIGURE 10
FIGURE 11
Page 11
Download from Www.Somanuals.com. All Manuals Search And Download.
Setting an Upflow Unit
tions.
When the side return air inlets are used in an upflow ap-
plication, it may be necessary to install leveling bolts on the
bottom of the furnace. Use field−supplied corrosion−resist-
Downflow Application Installation Clearances
Top
NOTE − The maximum length of the bolt is 1−1/2 inches.
1 − Lie the furnace on its back and drill a 5/16 inch diame-
ter hole in each corner of the furnace’s bottom. See fig-
ure 12 for the correct location of the holes. Drill through
the bottom panel and the bottom flange of the cabinet.
2 − Install one bolt and two nuts into each hole. Screw the
first nut onto a bolt and then insert the bolt into a hole. A
flat washer may be added between the nut and the bot-
tom of the unit.
Left Side
Right Side
Bottom
3 − Screw another nut onto the bolt on the inside of the fur-
nace base. A flat washer may be added between the
nut and the bottom of the unit.
Top
*Front
Back
Sides
Vent
0
0
4 − Adjust the outside nut to the appropriate height and
tighten the inside nut to secure the arrangement.
0
0†
0
NOTE − The unit may be tilted back−to−front a maximum of
1". This will ensure proper draining of the heat exchanger.
Floor
NC‡
Leveling Bolt Installation
*Front clearance in alcove installation must be 24 in. (610 mm).
Maintain a minimum of 24 in. (610 mm) for front service access.
†Allow proper clearances to accommodate condensate trap and
vent pipe installation.
Inches (mm)
3/8
(10)
Furnace Front
‡The furnace may be installed on a combustible wood floor if an op-
tional additive base is installed between the furnace and the com-
bustible floor.
1−3/4
(44)
3/8
(10)
FIGURE 13
Installation on Non−Combustible Flooring
1−3/4
(44)
1 − Cut floor opening keeping in mind clearances listed on
unit rating plate. Also keep in mind gas supply connec-
tions, electrical supply, flue and air intake connections
and sufficient installation and servicing clearances.
See table 1 for correct floor opening size.
2 − Flange warm air plenum and lower the plenum into the
opening.
Leveling Bolt
Locations
Furnace
Bottom
3/8
(10)
Leveling Bolt
Locations
3 − Set the unit over the plenum and seal the plenum to
the unit.
3/8
(10)
1−3/4
(44)
4 − Ensure that the seal is adequate.
1−3/4 (44)
NON−COMBUSTIBLE FLOOR OPENING SIZE
FIGURE 12
Front to Rear
Side to Side
Downflow Applications
Model No.
in.
mm
502
502
502
in.
mm
422
511
600
The unit may be installed three ways in downflow applica-
tions: on non−combustible flooring, on combustible flooring
using an additive base, or on a reverse−flow cooling cabi-
net. Do not drag the unit across the floor in the down-
flow position. Flange damage will result.
B Cabinet (17.5")
C Cabinet (21")
D Cabinet (24.5")
19 − 3/4
19 − 3/4
19 − 3/4
16 − 5/8
20−1/8
23 − 5/8
After unit has been properly set in place, position provided
logo over existing logo and affix sticker on front panel.
NOTE − Floor opening dimensions listed are 1/4 inch (6 mm) larger than
the unit opening. See dimension drawing on page 2.
Page 12
Download from Www.Somanuals.com. All Manuals Search And Download.
Installation on Combustible Flooring
(Using an Additive Base)
Installation on Cooling Coil Cabinet
1 − Refer to reverse−flow coil installation instructions for
correctly sized opening in floor and installation of cabi-
net.
1 − When unit is installed on a combustible floor, an addi-
tive base must be installed between the furnace and
the floor. The base must be ordered separately. See
table 2 for opening size to cut in floor.
2 − When cooling cabinet is in place, set and secure the
furnace according to the instructions that are provided
with the cooling coil. Secure the furnace to the cabinet.
CAUTION
The furnace and additive base shall not be installed
directly on carpeting, tile, or other combustible ma-
terial other than wood flooring.
3 − Seal the cabinet and check for air leaks.
Return Air Opening −− Downflow Units
Return air may be brought in only through the top opening
of a furnace installed in the downflow position.The follow-
ing steps should be taken when installing plenum:
ADDITIVE BASE FLOOR OPENING SIZE
Front to Rear
Side to Side
Cabinet
Width
Catalog
Number
1 − Bottom edge of plenum should be flanged with a
in.
22
mm
559
in.
mm
476
B Cabinet
(17.5")
11M60
11M61
11M62
18 − 3/4
2 − Sealing strips should be used to ensure an airtight seal
between the cabinet and the plenum.
C Cabinet
(21")
22
22
559
559
22 − 3/4
25 − 3/4
578
654
3 − In all cases, plenum should be secured to top of fur-
nace using sheet metal screws.
D Cabinet
(24.5")
4 − Make certain that an adequate seal is made.
2 − After opening is cut, set additive base into opening.
3 − Check fiberglass strips on additive base to make sure
they are properly glued and positioned.
PLENUM
4 − Lower supply air plenum into additive base until ple-
num flanges seal against fiberglass strips.
SECURE FROM
(Field Provided)
OUTSIDE CABINET
CABINET
NOTE − Be careful not to damage fiberglass strips.
Check for a tight seal.
5 − Set the furnace over the plenum.
SEALING STRIP
SIDE PANEL
6 − Ensure that the seal between the furnace and plenum
is adequate.
(Field Provided)
Side View
FIGURE 15
G61MP UNIT
PLENUM
SUPPLY AIR PLENUM
(Field Provided)
SEALING STRIP
PROPERLY
SIZED FLOOR
OPENING
(Field Provided)
ADDITIVE BASE
CABINET
SIDE PANEL
SECURE FROM
INSIDE CABINET
Side View
FIGURE 16
FIGURE 14
Page 13
Download from Www.Somanuals.com. All Manuals Search And Download.
3 − If unit is installed above finished space, fabricate a
drain pan fitted with a 1/2 inch or 3/4 inch N.P.T. fitting.
Horizontal Applications
The G61MP furnace can be installed in horizontal applica-
tions with either right− or left−hand air discharge.
4 − Using 3/8 inch rods and support frame kit or field−fabri-
cated supports, fabricate suspension hangers, keep-
ing in mind front service access clearances.
The G61MP may also be installed as a unit heater. Either
furnace on a field−fabricated raised platform. The unit
must be supported at both ends and beneath the blower
deck to prevent sagging.
6 − Continue with exhaust, condensate and intake line
piping instructions.
7 − If unit is suspended above finished space, hang the
field−provided drain pan below the support frame as
clearance below unit for condensate trap.
Horizontal Application
Installation Clearances
Right−Hand Discharge
Top
8 − Route auxiliary drain line so that water draining from
this outlet will be easily noticed by the homeowner. If
necessary, run the condensate line into a condensate
pump to meet drain line slope requirements. The
pump must be rated for use with condensing furnaces.
Protect the condensate discharge line from the pump
to the outside to avoid freezing.
Left End
Right End
Bottom (Floor)**
Left−Hand Discharge
Top
TYPICAL HORIZONTAL CEILING APPLICATION
BLOWER ACCESS PANEL
3/8 in. RODS
Left End
Right End
INTAKE/EXHAUST
CONNECTION
Bottom (Floor)**
Top
0
0
0
0
0
Front*
Back
Ends
Vent
Floor
0‡
DRAIN PAN
(to protect finished space)
*Front clearance in alcove installation must be 24 in. (610 mm).
Maintain a minimum of 24 in. (610 mm) for front service access.
**A 5−1/2ꢀ service clearance must be maintained below the unit to
provide for servicing of the condensate trap.
SUPPORT FRAME
FIGURE 18
‡For installations on a combustible floor, do not install the furnace
directly on carpeting, tile or other combustible materials other
than wood flooring.
Platform Installation of Horizontal Unit
1 − Select location for unit keeping in mind service and
FIGURE 17
Suspended Installation of Horizontal Unit
2 − Construct a raised wooden frame and cover frame
with a plywood sheet. Provide a service platform in
front of unit. If unit is installed above finished space,
fabricate a drain pan to be installed under unit.
NOTE − If unit is suspended in attic or crawl space, horizon-
tal support kit (Cat No. 56J18 ordered separately) must be
used to ensure proper unit support and coil drainage.
1 − Select location for unit keeping in mind service and
When installing the unit in a crawl space, a proper sup-
port platform may be created using cement blocks and
the horizontal support frame kit (ordered separately,
2 − Provide service platform in front of unit.
Page 14
Download from Www.Somanuals.com. All Manuals Search And Download.
Lennox part number 56J18). Position the support
frame on top of the blocks and install the unit on the
frame. Leave 5−1/2 inches for service clearance for
condensate trap.
Unit Heater Discharge Duct Guidelines
A field−fabricated and installed discharge air duct and grille
cabinet is suitable for use with the G61MP heater. Keep the
following items in mind when constructing the cabinet.
1 − Outer dimensions of cabinet should match those of the
unit heater, so the duct/grille cabinet installs flush with
3 − Route auxiliary drain line so that water draining from
this outlet will be easily noticed by the homeowner. If
necessary, run the condensate line into a condensate
pump to meet drain line slope requirements. The
pump must be rated for use with condensing furnaces.
Protect the condensate discharge line from the pump
to the outside to avoid freezing.
2 − Flange both ends of duct/grille cabinet so that screws
can be used to secure cabinet to discharge end of unit
heater.
3 − To ensure proper operation, the duct/grille cabinet
must be at least 18 inches long.
inches for service clearance below unit for condensate
trap.
4 − Use #10−16 x 1/2 inch sheet metal screws to secure
duct/grille cabinet to unit, taking care not to damage in-
ternal components of unit heater when drilling holes or
5 − Continue with exhaust, condensate and intake piping
installation according to instructions.
5 − Use adjustable, double−deflection grille(s) to distribute
discharge air. Adjust static pressure to be in the 0.06
inch to 0.10 inch w.c. range.
EXHAUST PIPE
INTAKE PIPE
*GAS
CONNECTOR
*Gas connector may be
used for Canadian
installation if accept-
able by local authority
having jurisdiction.
18 in.
MIN.
RAISED
DRAIN PAN
(to protect
finished
PLATFORM
CONDENSATE LINE
SERVICE PLATFORM
space)
FIGURE 19
NOTE − When installing duct/grille cabinet, take care not to damage internal unit
heater components when drilling holes or installing screws.
G61MP Installed in Unit Heater Applications
FIGURE 20
The G61MP may also be installed as a unit heater. Either
suspend the furnace from roof rafters or floor joists, as
be supported at both ends and beneath the blower deck to
prevent sagging. The condensate trap must be installed
where it can be serviced at a later date.
Return Air −− Horizontal Applications
Return air may be brought in only through the end of a fur-
nace installed in the horizontal position. The furnace is
equipped with a removable bottom panel to facilitate
Page 15
Download from Www.Somanuals.com. All Manuals Search And Download.
Filters
Pipe & Fittings Specifications
This unit is not equipped with a filter or rack. A field−pro-
vided filter is required for the unit to operate properly. Table
3 lists recommended filter sizes.
All pipe, fittings, primer and solvent cement must conform
with American National Standard Institute and the Ameri-
can Society for Testing and Materials (ANSI/ASTM) stan-
dards. The solvent shall be free flowing and contain no
lumps, undissolved particles or any foreign matter that ad-
versely affects the joint strength or chemical resistance of
the cement. The cement shall show no gelation, stratifica-
tion, or separation that cannot be removed by stirring. Re-
A filter must be in place whenever the unit is operating.
TABLE 3
Filter Size
Furnace
Cabinet Width
Side Return
Bottom Return
16 X 25 X 1 (1)
20 X 25 X 1 (1)
24 X 25 X 1 (1)
17−1/2"
21"
16 X 25 X 1 (1)
16 X 25 X 1 (1)
16 X 25 X 1 (2)
24−1/2"
CAUTION
Duct System
Solvent cements for plastic pipe are flammable liq-
uids and should be kept away from all sources of
ignition. Do not use excessive amounts of solvent
cement when making joints. Good ventilation should
be maintained to reduce fire hazard and to minimize
breathing of solvent vapors. Avoid contact of cement
with skin and eyes.
Use industry-approved standards to size and install the
supply and return air duct system. This will result in a quiet
and low-static system that has uniform air distribution.
NOTE − Operation of this furnace in heating mode (indoor
blower operating at selected heating speed) with an exter-
nal static pressure which exceeds 0.5 inches w.c. may re-
sult in erratic limit operation.
TABLE 4
PIPING AND FITTINGS SPECIFICATIONS
Supply Air Plenum
ASTM
PIPE & FITTING MATERIAL
If the furnace is installed without a cooling coil, a removable
access panel should be installed in the supply air duct. The
access panel should be large enough to permit inspection
(by reflected light) of the heat exchanger for leaks after the
furnace is installed. If present, this access panel must al-
ways be in place when the furnace is operating and it must
not allow leaks into the supply air duct system.
SPECIFICATION
Schedule 40 PVC (Pipe)
D1785
F891
Schedule 40 PVC (Cellular Core Pipe)
Schedule 40 PVC (Fittings)
D2466
F441
Schedule 40 CPVC (Pipe)
Schedule 40 CPVC (Fittings)
SDR−21 PVC or SDR−26 PVC (Pipe)
SDR−21 CPVC or SDR−26 CPVC (Pipe)
Schedule 40 ABS Cellular Core DWV (Pipe)
Schedule 40 ABS (Pipe)
F438
D2241
F442
Return Air Plenum
F628
NOTE − Return air must not be drawn from a room
where this furnace, or any other gas−fueled ap-
pliance (i.e., water heater), or carbon monoxide−
producing device (i.e., wood fireplace) is installed.
D1527
D2468
Schedule 40 ABS (Fittings)
ABS−DWV (Drain Waste & Vent)
(Pipe & Fittings)
D2661
D2665
When return air is drawn from a room, a negative pres-
sure is created in the room. If a gas appliance is operating
in a room with negative pressure, the flue products can
be pulled back down the vent pipe and into the room. This
reverse flow of the flue gas may result in incomplete com-
bustion and the formation of carbon monoxide gas. This
toxic gas might then be distributed throughout the house
by the furnace duct system.
PVC−DWV (Drain Waste & Vent)
Pipe & Fittings)
ASTM
SPECIFICATION
PRIMER & SOLVENT CEMENT
PVC & CPVC Primer
PVC Solvent Cement
CPVC Solvent Cement
ABS Solvent Cement
F656
D2564
F493
D2235
PVC/CPVC/ABS All Purpose Cement For Fit-
tings & Pipe of the same material
D2564, D2235,
F493
Return air can be brought in through the bottom or either
side of the furnace. If a furnace with bottom return air is
installed on a platform, make an airtight seal between the
bottom of the furnace and the platform to ensure that the
unit operates properly and safely. Use fiberglass sealing
strips, caulking, or equivalent sealing method between the
plenum and the furnace cabinet to ensure a tight seal. If a
filter is installed, size the return air duct to fit the filter frame.
ABS to PVC or CPVC Transition Solvent
Cement
D3138
CANADA PIPE & FITTING & SOLVENT
CEMENT
MARKING
PVC & CPVC Pipe and Fittings
PVC & CPVC Solvent Cement
ULCS636
ABS to PVC or CPVC Transition Cement
Page 16
Download from Www.Somanuals.com. All Manuals Search And Download.
Use PVC primer and solvent cement or ABS solvent cement
nate, use all purpose cement, to bond ABS, PVC, or CPVC
pipe when using fittings and pipe made of the same materi-
als. Use transition solvent cement when bonding ABS to ei-
ther PVC or CPVC.
Canadian Applications Only − Pipe, fittings, primer
and solvent cement used to vent (exhaust) this ap-
pliance must be certified to ULC S636 and supplied by a
single manufacturer as part of an approved vent (ex-
haust) system. When bonding the vent system to the fur-
nace, use ULC S636 approved One−Step Transition Ce-
ment to bond the pipe to the flue collar, or to bond the 90°
elbow or reducing 90° elbow to the flue collar. In addi-
tion, the first three feet of vent pipe from the furnace flue
collar must be accessible for inspection.
Low temperature solvent cement is recommended. Metal or
plastic strapping may be used for vent pipe hangers. Uni-
formly apply a liberal coat of PVC primer for PVC or use a
clean dry cloth for ABS to clean inside socket surface of fit-
ting and male end of pipe to depth of fitting socket.
as vent pipe equivalencies which must be used when siz-
ing vent pipe. All Lennox vent terminations are PVC.
TABLE 5
OUTDOOR TERMINATION KITS AND CORRESPONDING EQUIVALENCIES
Vent Pipe Length Equivalency (feet)
Outdoor Ex- Outdoor Ex-
haust Accel- haust Accel-
1−1/2"
Concentric
Kit
VENT
PIPE
DIA.
2" Con- 3" Con-
centric Kit centric Kit
2" Wall Plate 3" Wall Plate
Kit
2" Wall
Ring Kit
erator
(Dia. X
Length)
erator
(Dia. X
Length)
UNIT
MODEL
Kit
(in.)
71M80
69M29
60L46
22G44
or 44W92ꢀ or 44W92ꢀ or 44W93ꢀ or 30G28ꢀ
44J40
or 81J20ꢀ
1−1/2" X 12"
2" X 12"
15F74
Not
Allowed
Not
Allowed
Not
Allowed
2
4
5
12
15
21
42
12
15
24
42
4
5
4*
5*
7*
14*
4*
5*
8*
14*
1
4
5
Not
Allowed
Not
Allowed
Not
Allowed
2−1/2
36B−045
Not
Allowed
Not
Allowed
Not
Allowed
3
7
7
7
Not
Allowed
Not
Allowed
Not
Allowed
4
14
4
14
4
14
4
Not
Allowed
Not
Allowed
Not
Allowed
2
Not
Allowed
Not
Allowed
Not
Allowed
2−1/2
5
5
5
36B−070
36B−071
Not
Allowed
Not
Allowed
Not
Allowed
3
8
8
8
Not
Allowed
Not
Allowed
Not
Allowed
4
14
14
14
1**
2**
2**
4**
2
Not
Allowed
Not
Allowed
Not
Allowed
2
2−1/2
3
1
2
2
4
2
2
4
3
6
3
6
Not
Allowed
Not
Allowed
Not
Allowed
2
48C−090
60C−090
60C−091
Not
Allowed
Not
Allowed
Not
Allowed
6
6
2
Not
Allowed
Not
Allowed
Not
Allowed
4
12
6
12
6
4
Not
Allowed
Not
Allowed
Not
Allowed
2−1/2
3
2
48C−110
60C−110
60C−111
Not
Allowed
Not
Allowed
Not
Allowed
6
6
2
2
Not
Allowed
Not
Allowed
Not
Allowed
4
12
12
4
4
Not
Allowed
Not
Allowed
Not
Allowed
Not
Allowed
Not
Allowed
3
4
6
15
25
6
60D−135
Not
Allowed
Not
Allowed
Not
Allowed
Not
Allowed
Not
Allowed
10
10
*Requires field−provided and installed 1−1/2" exhaust accelerator.
**Requires field−provided and installed 2" exhaust accelerator.
ꢀ Termination kits 44W92 (includes 1−1/2" reducer), 44W93,
30G28 and 81J20 approved for use in Canadian installations.
Page 17
Download from Www.Somanuals.com. All Manuals Search And Download.
Vent Piping Guidelines
The G61MP can be installed as either a Non−Direct Vent
or a Direct Vent gas central furnace.
leased from the exhaust termination. The minimum ex-
haust vent length is 15 ft. Shorter exhaust vent lengths may
result in the discharge of water droplets from the exhaust
termination, in spite of the 12−inch vertical offset. See fig-
NOTE − In Non-Direct Vent installations, combustion air is
taken from indoors and flue gases are discharged outdoors.
In Direct Vent installations, combustion air is taken from out-
doors and flue gases are discharged outdoors.
Each 90° elbow (including those provided with the furnace)
of any diameter is equivalent to 5 feet (1.52m) of vent pipe
of the same diameter. Two 45° elbows are equivalent to
one 90° elbow of the same diameter. One 45° elbow is
equal to 2.5 feet (.76m) of vent pipe of the same diameter.
Intake and exhaust pipe sizing in Direct Vent applications
and exhaust pipe sizing in Non-Direct Vent applications −−
the maximum equivalent pipe lengths permitted.
In some applications which permit the use of several differ-
ent sizes of vent pipe, a combination vent pipe may be
used. Contact the Application Department for assistance in
sizing vent pipe in these applications.
Maximum vent length is defined as:
Total length (linear feet) of pipe,
Plus Equivalent length (feet) of fittings,
Plus Equivalent length (feet) of termination.
NOTE − Include ALL pipe and ALL fittings, both in
doors and outdoors.
NOTE − The flue collar on all models is sized to accommo-
date 2" Schedule 40 flue pipe. When vent pipe which is
larger than 2" must be used in an upflow application, a 2"
elbow must be applied at the flue collar in order to proper-
ly transition to the larger diameter flue pipe. This elbow
must be added to the elbow count used to determine ac-
ceptable vent lengths. Assign an equivalent feet value to
this elbow according to the larger size pipe being used.
Contact Lennox’ Application Department for more infor-
mation concerning sizing of vent systems which include
multiple pipe sizes.
Regardless of the diameter of pipe used, the standard roof
and wall terminations described in section Exhaust Piping
Terminations should be used. Exhaust vent termination
pipe is sized to optimize the velocity of the exhaust gas as
*NOTE − The exhaust pipe should be offset a minimum of
12 inches to avoid the possibility of water droplets being re-
Exhaust Pipe Offset
12" Min.
*12" Min.
Upflow and Downflow Application
Rooftop Termination
Upflow and Downflow Application
Side Wall Termination
*12" Min.
*12" Min.
Horizontal Application
Rooftop Termination
Horizontal Application
Side Wall Termination
*A minimum of 1/4" (6mm) drop for each 12" (305mm) of horizontal run is mandatory for drainage
FIGURE 21
Page 18
Download from Www.Somanuals.com. All Manuals Search And Download.
Use the following steps to correctly size vent pipe diameter.
Refer to Vent Pipe Size Determination Worksheet on
page 53.
TABLE 7
MAXIMUM VENT PIPE LENGTHS
MAXIMUM EQUIVALENT VENT
LENGTH FEET
G61MP
MODEL
1 − Determine the vent termination and its corresponding
equivalent feet value according to table 5.
ALTITUDE
2"
PIPE
2−1/2"
PIPE
3"
PIPE
4"
PIPE
2 − Determine the number of 90° elbows required for both
indoor and outdoor (e.g. snow riser) use. Calculate the
corresponding equivalent feet of vent pipe.
045
070
59
59
59
26
26
n/a
n/a
n/a
59
59
59
26
26
n/a
n/a
n/a
59
59
59
26
26
n/a
n/a
n/a
65
65
65
42
42
32
32
n/a
65
65
65
42
42
32
32
n/a
65
65
65
42
42
32
32
n/a
77
78
78
72
72
72
72
61
77
78
78
72
72
72
72
46
77
78
78
72
72
72
72
46
234
214
214
204
204
179
179
160
234
214
214
204
204
179
179
160
234
214
214
204
204
179
179
160
071†
090
0 − 4500
(0 − 1371 m)
3 − Determine the number of 45° elbows required for both
indoor and outdoor use. Calculate the corresponding
equivalent feet of vent pipe.
091†
110*
111*†
135**‡
045
4 − Determine the length of straight pipe required.
5 − Add the total equivalent feet calculated in steps 1
through 4 and compare that length to the maximum
values given in table 6 for the proposed vent pipe di-
ameter. If the total equivalent length required exceeds
the maximum equivalent length listed in the appropri-
ate table, evaluate the next larger size pipe.
070
071†
090
4501−7500
(1372−2286 m)
091†
110*
111*†
135**‡
045
TABLE 6
MINIMUM VENT PIPE LENGTHS
070
071†
090
G61MP
MODEL
MIN. EQUIV.
VENT LENGTH
EXAMPLE
7501 − 10000
(2287 − 3048 m)
091†
110*
111*†
135**‡
045, 070,
071, 090,
091
5 ft. plus 2 elbows of 2", 2−1/2", 3"
or 4" diameter pipe
5 ft. plus 2 elbows of 2−1/2" 3" or 4"
diameter pipe
15 ft.*
n/a −− Not allowed.
110, 111**
135***
*G61MP−48C−110, G61MP−60C−110 and G61MP−60C−111must have 90°
street ell (supplied or field replacment Canadian ki) installed directly into unit
flue collar.
5 ft. plus 2 elbows of 3" or 4"
diameter pipe
**G61MP−60D−135 must have 3" to 2" reducing ell (supplied or field replacment
Canadian ki) installed directly into unit flue collar.
*Any approved termination may be added to the minimum equivalent length
listed.
***90° elbows used in configuration of G61MP−60D−135 vent, must be lim-
ited to 3" sweep elbows.
**G61MP−48C−110, G61MP−60C−110 and G61MP−60C−111 must have 90°
street ell (supplied or field replacment Canadian kit) installed directly into unit
flue collar.
†On G61MP−071, −091 and −111 units, sweep elbows must be used for
all 90° elbows in the venting system when 2", 2−1/2" or 3" vent pipe is
used. Sweep elbows are recommended for use in vent systems of
other G61MP units.
***G61MP−60D−135 must have 3" to 2" reducing ell (supplied or field replac-
ment Canadian ki) installed directly into unit flue collar.
Page 19
Download from Www.Somanuals.com. All Manuals Search And Download.
NOTE − Furnace flue collar and air inlet fitting are both
made of ABS material. Use transition solvent cement
when bonding ABS to either PVC or CPVC, refer to the
procedure specified in ASTM D3138..
Joint Cementing Procedure
All cementing of joints should be done according to the
specifications outlined in ASTM D 2855.
6 − Promptly apply solvent cement to end of pipe and in-
side socket surface of fitting. Cement should be ap-
plied lightly but uniformly to inside of socket. Take
care to keep excess cement out of socket. Apply sec-
ond coat to end of pipe.
WARNING
DANGER OF EXPLOSION!
NOTE − Time is critical at this stage. Do not allow prim-
Fumes from PVC glue may ignite during system
check. Allow fumes to dissipate for at least 5 minutes
before placing unit into operation.
er to dry before applying cement.
7 − Immediately after applying last coat of cement to pipe,
and while both inside socket surface and end of pipe
are wet with cement, forcefully insert end of pipe into
socket until it bottoms out. Turn PVC pipe 1/4 turn dur-
ing assembly (but not after pipe is fully inserted) to dis-
tribute cement evenly. DO NOT turn ABS or cellular
core pipe.
1 − Measure and cut vent pipe to desired length.
2 − Debur and chamfer end of pipe, removing any ridges
or rough edges. If end is not chamfered, edge of pipe
may remove cement from fitting socket and result in a
leaking joint.
NOTE − Assembly should be completed within 20 sec-
onds after last application of cement. Hammer blows
should not be used when inserting pipe.
3 − Clean and dry surfaces to be joined.
4 − Test fit joint and mark depth of fitting on outside of pipe.
8 − After assembly, wipe excess cement from pipe at end
of fitting socket. A properly made joint will show a
bead around its entire perimeter. Any gaps may indi-
cate a defective assembly due to insufficient solvent.
5 − Uniformly apply a liberal coat of PVC primer for PVC or
use a clean dry cloth for ABS to clean inside socket
surface of fitting and male end of pipe to depth of fitting
socket.
9 − Handle joints carefully until completely set.
Page 20
Download from Www.Somanuals.com. All Manuals Search And Download.
4 − Isolate piping at the point where it exits the outside wall
or roof in order to prevent transmission of vibration to
the structure.
Venting Practices
The thickness of construction through which vent pipes
may be installed is 24" (610mm) maximum and 3" (76mm)
minimum. If a G61MP furnace replaces a furnace which
was commonly vented with another gas appliance, the size
of the existing vent pipe for that gas appliance must be
checked. Without the heat of the original furnace flue prod-
ucts, the existing vent pipe is probably oversized for the
single water heater or other appliance. The vent should be
checked for proper draw with the remaining appliance.
5 − When furnace is installed in a residence where unit is
shut down for an extended period of time, such as a
vacation home, make provisions for draining conden-
sate collection trap and lines.
Exhaust Piping
NOTE − A 2" diameter PVC street ell is located on the
blower deck of 48C−110, 60C−110 and 60C−111 units. In
upflow or downflow applicationsthestreet ellmust be
glued using transition solvent cement directly into the
located on the blower deck of the 60D−135 units. In up-
flow or downflow applications, the reducing ell must
be glued using transition solvent cement directly into the
unit flue collar.
1 − Use recommended piping materials for exhaust pip-
ing.
2 − Secure all joints so that they are gas-tight using ap-
proved cement.
Suspend piping using hangers at a minimum of every 5
feet (1.52m) for schedule
40 PVC and every 3 feet
(.91m) for ABS−DWV, PVC−
DWV, SPR−21 PVC, and
SDR−26 PVC piping. A suit-
able hanger can be fabri-
cated by using metal or
plastic strapping or a large
wire tie.
STRAPPING
(metal, plastic
or large wire
ties)
1 − Choose the appropriate side for venting in upflow or
downflow positions. Exhaust piping exits from the top
of the unit in horizontal air discharge applications.
Glue the field−provided exhaust vent pipe (or provided
street ell or reducing ell in upflow or downflow applica-
tions) to the flue collar. All PVC cement joints should
be made according to the specifications outlined in
ASTM D 2855. Refer to pipe and fittings specifications
and gluing procedures.
FIGURE 22
3 − In areas where piping penetrates joists or interior
walls, hole must be large enough to allow clearance on
all sides of pipe through center of hole using a hanger.
TYPICAL EXHAUST PIPE CONNECTIONS AND CONDENSATE TRAP INSTALLATION
IN UPFLOW OR DOWNFLOW DIRECT OR NON−DIRECT VENT APPLICATIONS
(Right−Hand Exit in Upflow Application Shown)
45°
MAX
45°
MAX
2−1/2",
3", OR
4"
2"
PLUG
PLUG
TRANSITION
or
**2"
2"
G61MP−045,
−070, −071 or
−090, −091 with
2−1/2", 3", or 4"
vent pipe
2"
2"
SIDE VIEW
VENT PLUG
(Must be
glued in
2"
place)
4"
2−1/2",
3", OR
4"
PLUG
TRANSITION
(use only if 4"
pipe is
CONDENSATE
TRAP
(Must be installed
on same side as
exhaust piping)
TRANSITION
required)
2" max
length
2" max
length
*2"
3" to 2" REDUCING ELBOW
(provided)
G61MP−110, −111 with
2−1/2", 3", OR 4" vent
pipe
*2" diameter street elbow provided.
G61MP−135, −110, −111
with
3" OR 4" vent pipe
**Street elbow may be used on −045, −070, 071, −090 and −091.
FIGURE 23
Page 21
Download from Www.Somanuals.com. All Manuals Search And Download.
TYPICAL EXHAUST PIPE CONNECTIONS
HORIZONTAL DIRECT OR NON−DIRECT VENT
APPLICATIONS
CAUTION
Do not discharge exhaust into an existing stack or
stack that also serves another gas appliance. If verti-
cal discharge through an existing unused stack is re-
quired, insert PVC pipe inside the stack until the end
is even with the top or outlet end of the metal stack.
(Horizontal Right−Hand Air
Discharge Application Shown)
* 2" maximum length
for −110, −111 −135 only
36B−045
2−1/2",
3", OR
4"
36B−070
36B−071
48C−090
60C−090
60C−091
48C−110
60C−110*
60C−111*
60D−135*
TRANSITION
*2"
CAUTION
The exhaust vent pipe operates under positive pres-
sure and must be completely sealed to prevent leak-
age of combustion products into the living space.
2"
2"
36B−045
36B−070
36B−071
36C−090
60C−090
60C−091
DO NOT transition
from smaller to larger
pipe size in horizontal
runs of exhaust pipe.
Intake Piping
2"
The G61MP furnace may be installed in either direct vent
or non−direct vent applications. In non−direct vent applica-
tions, when intake air will be drawn into the furnace from the
surrounding space, the indoor air quality must be consid-
ered and guidelines listed in Combustion, Dilution and Ven-
tilation Air section must be followed.
The G61MP unit is designed for either left−side or right−side
air intake connections in either upflow or downflow applica-
tions. In horizontal applications, air intake must be brought
in through the top. Intake air piping is independent of ex-
haust piping.
Follow the next four steps when installing the unit in direct
vent applications, where combustion air is taken from out-
doors and flue gases are discharged outdoors. The pro-
vided air intake screen must not be used in direct vent ap-
plications.
FIGURE 24
IMPORTANT
Exhaust piping and condensate trap must be
installed on the same side of the unit in upflow and
dowflow applications or use alternate drain kit
76M20.
1 − Use transition solvent cement to connect PVC pipe to
the ABS slip connector located on the side of the burn-
er box.
2 − All horizontal runs of exhaust pipe must slope back to-
ward unit. A minimum of 1/4" (6mm) drop for each 12"
(305mm) of horizontal run is mandatory for drainage.
Horizontal runs of exhaust piping must be supported ev-
ery 5 feet (1.52m) using hangers.
2 − Use a #7 sheet metal screw to secure the intake pipe to
the connector, if desired. A pilot indentation is provided in
the slip connector to assist in locating and starting the fas-
tener.
NOTE − Exhaust piping should be checked carefully to
3 − Glue the provided 2" ABS plug into the unused ABS air
intake connector on the opposite side of the cabinet with
ABS all pupose cement.
make sure there are no sags or low spots.
3 − On the opposite side of the cabinet, glue the provided
2" ABS vent plug into the unused ABS flue collar with
ABS or all purpose solvent cement.
4 − Route piping to outside of structure. Continue with instal-
lation following instructions given in general guide lines for
piping terminations and in intake and exhaust piping ter-
pipe sizes.
4 − Route piping to outside of structure. Continue with
installation following instructions given in piping ter-
mination section.
Page 22
Download from Www.Somanuals.com. All Manuals Search And Download.
TYPICAL AIR INTAKE PIPE CONNECTIONS
UPFLOW OR DOWNFLOW DIRECT VENT APPLICATIONS
(Right−Hand Exit in Upflow Application Shown)
2−1/2",
3" OR
4ꢁ
2−1/2",
3" OR
4ꢁ
TRANSITION
2ꢁ
2ꢁ
TRANSITION
*2"
2ꢁ
2ꢁ
2ꢁ
2ꢁ
PLUG
(Must be
glued in
place)
−36B−045−
−36B−070
−36B−071
−48C−090
−60C−090
−60C−091
−36B−045
−36B−070
−36B−071
−48C−090
−60C−090
−60C−091
−48C−110
−60C−110*
−60C−111*
−60D−135*
−36B−045
−36B−070
−36B−071
−48C−090
−60C−090
−60C−091
−48C−110
−60C−110
−60C−111
*Limit pipe length to 4" in G61MP−110,
−111, −135 applications.
FIGURE 25
Follow the next three steps when installing the unit in Non-
Direct Vent applications where combustion air is taken
from indoors and flue gases are discharged outdoors.
TYPICAL AIR INTAKE PIPE CONNECTIONS
HORIZONTAL DIRECT VENT APPLICATIONS
(Horizontal Right−Hand Air Discharge Application Shown)
−36B−045
*Limit pipe
length to 4" in −110, −111,
−135 applications.
−36B−070
−36B−071
−48C−090
−60C−090
−60C−091
−48C−110
−60C−110*
−60C−111
−60D−135*
2−1/2”,
TYPICAL AIR INTAKE PIPE CONNECTIONS
UPFLOW OR HORIZONTAL NON−DIRECT
VENT APPLICATIONS
3” OR 4”
(Right−Hand Exit in Upflow Application Shown)
TRANSITION
6 in. Max.
*2”
2−1/2”,
3” OR 4”
−36B−045
2”
−36B−070
−36B−071
−48C−090
−60C−090
−60C−091
−48C−110
−60C−110
−60C−111
2”
PLUG
(Must be
TRANSITION
glued in
INTAKE
place)
2”
DEBRIS
SCREEN
(Provided)
2”
2”
−36B−045
−36B−070
−36B−071
−48C−090
−60C−090
−60C−091
2”
NOTE − Debris screen and elbow may be rotated, so that
screen may be positioned to face forward, backward or
downward.
FIGURE 27
FIGURE 26
Page 23
Download from Www.Somanuals.com. All Manuals Search And Download.
TYPICAL AIR INTAKE PIPE CONNECTIONS
DOWNFLOW NON−DIRECT VENT APPLICATIONS
(Right−Hand Exit in Downflow Applications Shown)
2" SWEEP
ELL
INTAKE
DEBRIS
SCREEN
(Provided)
6 in. Max.
PLUG
PLUG
(Must be
glued in
place)
(Must be
glued in
place)
2"
18 in.
2" SWEEP ELL
INTAKE DEBRIS
SCREEN
(Provided)
Downflow Additive Flloor Base
Downflow
Evaporator
Coil
NOTE − Debris screen and sweep ell may be rotated, so that
screen may be positioned to face forward, backward or to the side.
FIGURE 28
1 − Use field−provided materials and the factory−provided
air intake screen to route the intake piping as shown in
(76mm) around the air intake opening. The air intake
opening (with the protective screen) should always be
directed either downward or straight out. Use 2" pipe
and fittings only and make sure that the air intake does
not extend more than 6" beyond the G61MP cabinet.
The air intake connector must not be located near
the floor. To avoid this complication in downflow
applications which do not include a downflow
evaporator coil, the intake air routing should be modi-
2 − Use a #7 sheet metal screw to secure the intake pipe to
the connector, if desired. A pilot indentation is provided in
the slip connector to assist in locating and starting the fas-
tener.
3 − Glue the provided 2" ABS plug into the unused ABS air
intake connector on the opposite side of the cabinet with
ABS or all purpose solvent cement.
Page 24
Download from Www.Somanuals.com. All Manuals Search And Download.
General Guidelines for Vent Terminations
(13mm) Armaflex or equivalent. In extreme cold climate
areas, 3/4" (19mm) Armaflex or equivalent may be neces-
sary. Insulation on outside runs of exhaust pipe must be
painted or wrapped to protect insulation from deterioration.
Exhaust pipe insulation may not be necessary in some
specific applications.
In Non-Direct Vent applications, combustion air is taken
from indoors and the flue gases are discharged to the out-
doors. The G61MP is then classified as a non-direct vent,
Category IV gas furnace.
In Direct Vent applications, combustion air is taken from
outdoors and the flue gases are discharged to the out-
doors. The G61MP is then classified as a direct vent,
Category IV gas furnace.
NOTE − During extremely cold temperatures, below
approximately 20°F (6.7°C), units with long runs of vent
pipe through unconditioned space, even when insulated,
may form ice in the exhaust termination that prevents the
unit from operating properly. Longer run times of at least 5
minutes will alleviate most icing problems. Also, a heating
cable may be installed on exhaust piping and termination to
prevent freeze−ups. Heating cable installation kit is avail-
able from Lennox. See Condensate Piping section for part
numbers.
In both Non-Direct Vent and Direct Vent applications, the
vent termination is limited by local building codes. In the
absence of local codes, refer to the current National Fuel
Gas Code ANSI Z223−1/NFPA 54 in U.S.A., and current
CSA−B149 Natural Gas and Propane Installation Codes in
Canada for details.
Position termination according to location given in figure 29
obstructions and 12" above the average snow accumula-
tion.
IMPORTANT
Do not use screens or perforated metal in exhaust
terminations. Doing so will cause freeze−ups and
may block the terminations.
At vent termination, care must be taken to maintain
protective coatings over building materials (prolonged
exposure to exhaust condensate can destroy protective
coatings). It is recommended that the exhaust outlet not be
located within 6 feet (1.8m) of a condensing unit because
the condensate can damage the painted coating.
IMPORTANT
For Canadian Installations Only:
NOTE − If winter design temperature is below 32°F (0°C),
exhaust piping should be insulated with 1/2" (13mm), Ar-
maflex or equivalent when run through unheated space.
Do not leave any surface area of exhaust pipe open to out-
side air; exterior exhaust pipe should be insulated with 1/2"
In accordance to CSA International B149 installation
codes, the minimum allowed distance between the
combustion air intake inlet and the exhaust outlet of
other appliances shall not be less than 12 inches
(305mm).
Page 25
Download from Www.Somanuals.com. All Manuals Search And Download.
VENT TERMINATION CLEARANCES
FOR NON−DIRECT VENT INSTALLATIONS IN THE USA AND CANADA
INSIDE CORNER
DETAIL
G
H
A
D
E
B
L
B
Fixed
Closed
B
B
I
C
Operable
Fixed
Closed
M
F
Operable
K
J
A
B
AREA WHERE TERMINAL
IS NOT PERMITTED
AIR SUPPLY INLET
VENT TERMINAL
1
2
US Installations
Canadian Installations
A =
Clearance above grade, veranda,
porch, deck or balcony
12 inches (305mm) or 12 in. 305mm)
above average snow accumulation.
12 inches (305mm) or 12 in. 305mm)
above average snow accumulation.
B =
Clearance to window or
door that may be opened
6 inches (152mm) for appliances <10,000
Btuh (3kw), 12 inches (305mm) for
appliances > 10,000 Btuh (3kw) and
<100,000 Btuh (30kw), 36 inches (.9m)
for appliances > 100,000 Btuh (30kw)
4 feet (1.2 m) below or to side of opening;
1 foot (30 cm) above opening
C =
D =
Clearance to permanently
closed window
* 12"
* 12"
Vertical clearance to ventilated soffit
located above the terminal within a
horizontal distance of 2 feet (mm)
from the center line of the terminal
* Equal to or greater than soffit depth.
* Equal to or greater than soffit depth.
* Equal to or greater than soffit depth.
* No minimum to outside corner
* 3 feet (.9m)
E =
F =
Clearance to unventilated soffit
Clearance to outside corner
* Equal to or greater than soffit depth.
* No minimum to outside corner
* 3 feet (.9m)
G = Clearance to inside corner
H = Clearance to each side of center line ex-
tended above meter / regulator assembly
3 feet (.9m) within a height 15 feet (4.5m) 3 feet (.9m) within a height 15 feet (4.5m)
above the meter / regulator assembly
*
above the meter / regulator assembly
I =
Clearance to service regulator
vent outlet
3 feet (.9m)
* 3 feet (.9m)
J =
Clearance to non−mechanical air
supply inlet to building or the com-
bustion air inlet to any other ap-
pliance
6 inches (152mm) for appliances <10,000
Btuh (3kw), 12 inches (305mm) for
appliances > 10,000 Btuh (3kw) and
<100,000 Btuh (30kw), 36 inches (.9m)
for appliances > 100,000 Btuh (30kw)
4 feet (1.2 m) below or to side of opening;
1 foot (30 cm) above opening
K =
L =
Clearance to mechanical air sup-
ply inlet
3 feet (.9m) above if within 10 feet
(3m) horizontally
6 feet (1.8m)
Clearance above paved sidewalk or
paved driveway located on public property
7 feet (2.1m)ꢀ
7 feet (2.1m)ꢀ
M =
Clearance under veranda, porch,
deck or balcony
12 inches (305mm)ꢂ
*12 inches (305mm)ꢂ
1
In accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code
2
In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code
*For clearances not specified in ANSI Z223.1/NFPA 54 or CSA B149.1, clear-
ance will be in accordance with local installation codes and the requirements
of the gas supplier and these installation instructions."
ꢀ A vent shall not terminate directly above a sidewalk or paved driveway that is located
between two single family dwellings and serves both dwellings.
ꢂ Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two
sides beneath the floor. Lennox recommends avoiding this location if possible.
FIGURE 29
Page 26
Download from Www.Somanuals.com. All Manuals Search And Download.
VENT TERMINATION CLEARANCES
FOR DIRECT VENT INSTALLATIONS IN THE USA AND CANADA
INSIDE CORNER
DETAIL
G
H
A
D
E
B
L
B
Fixed
Closed
B
B
I
C
Operable
Fixed
Closed
M
F
Operable
K
J
A
B
AREA WHERE TERMINAL
IS NOT PERMITTED
AIR SUPPLY INLET
VENT TERMINAL
1
2
US Installations
Canadian Installations
A =
Clearance above grade, veranda,
porch, deck or balcony
12 inches (305mm) or 12 in. 305mm)
above average snow accumulation.
12 inches (305mm) or 12 in. 305mm)
above average snow accumulation.
B =
Clearance to window or
door that may be opened
6 inches (152mm) for appliances <10,000 6 inches (152mm) for appliances <10,000
Btuh (3kw), 9 inches (mm) for appliances
> 10,000 Btuh (3kw) and <50,000 Btuh
(15 kw), 12 inches (305mm) for ap-
pliances > 50,000 Btuh (15kw)
Btuh (3kw), 12 inches (305mm) for
appliances > 10,000 Btuh (3kw) and
<100,000 Btuh (30kw), 36 inches (.9m)
for appliances > 100,000 Btuh (30kw)
* 12"
C =
D =
Clearance to permanently
closed window
* 12"
Vertical clearance to ventilated soffit
located above the terminal within a
horizontal distance of 2 feet (mm)
from the center line of the terminal
* Equal to or greater than soffit depth
* Equal to or greater than soffit depth
* Equal to or greater than soffit depth
* No minimum to outside corner
* 3 feet (.9m)
* Equal to or greater than soffit depth
* No minimum to outside corner
E =
F =
G =
Clearance to unventilated soffit
Clearance to outside corner
Clearance to inside corner
* 3 feet (.9m)
H = Clearance to each side of center line ex-
tended above meter / regulator assembly
3 feet (.9m) within a height 15 feet (4.5m) 3 feet (.9m) within a height 15 feet (4.5m)
above the meter / regulator assembly
above the meter / regulator assembly
I =
Clearance to service regulator
vent outlet
3 feet (.9m)
* 3 feet (.9m)
J =
Clearance to non−mechanical air
supply inlet to building or the com-
bustion air inlet to any other ap-
pliance
6 inches (152mm) for appliances <10,000 6 inches (152mm) for appliances <10,000
Btuh (3kw), 9 inches (mm) for appliances
> 10,000 Btuh (3kw) and <50,000 Btuh
(15 kw), 12 inches (305mm) for ap-
pliances > 50,000 Btuh (15kw)
Btuh (3kw), 12 inches (305mm) for
appliances > 10,000 Btuh (3kw) and
<100,000 Btuh (30kw), 36 inches (.9m)
for appliances > 100,000 Btuh (30kw)
K =
L =
Clearance to mechanical air sup-
ply inlet
3 feet (.9m) above if within 10 feet
(3m) horizontally
6 feet (1.8m)
Clearance above paved sidewalk or
paved driveway located on public property
7 feet (2.1m)ꢀ
* 7 feet (2.1m)
M =
Clearance under veranda, porch,
deck or balcony
*12 inches (305mm)ꢂ
12 inches (305mm)ꢂ
1
In accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code
2
*For clearances not specified in ANSI Z223.1/NFPA 54 or CSA B149.1, clear-
ance will be in accordance with local installation codes and the requirements
of the gas supplier and these installation instructions."
In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code
ꢀ A vent shall not terminate directly above a sidewalk or paved driveway that is located
between two single family dwellings and serves both dwellings.
ꢂ Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two
sides beneath the floor. Lennox recommends avoiding this location if possible.
FIGURE 30
Page 27
Download from Www.Somanuals.com. All Manuals Search And Download.
Details of Intake and Exhaust Piping Terminations for
Direct Vent Installations
TABLE 8
EXHAUST PIPE TERMINATION SIZE REDUCTION
G61MP
Exhaust Pipe Size
Termination Pipe Size
NOTE − In Direct Vent installations, combustion air is taken
from outdoors and flue gases are discharged to outdoors.
MODEL
045, 070, −071
090, −091
110, −111
135
2", 2−1/2", 3" or 4"
2", 2−1/2", 3" or 4"
2−1/2", 3" or 4"
3" or 4"
1−1/2"
2"
Intake and exhaust pipes may be routed either horizontally
through an outside wall or vertically through the roof. In at-
tic or closet installations, vertical termination through the
minations.
*2"
*2"
*Approved 3" concentric termination kit terminates with 2−5/8" ID pipe.
3(76) MAX.
SIZE TERMINATION
PIPE PER TABLE 8.
Inches(mm)
1 − Exhaust and intake exits must be in same pressure
zone. Do not exit one through the roof and one on the
side. Also, do not exit the intake on one side and the
exhaust on another side of the house or structure.
UNCONDITIONED
ATTIC SPACE
8" (203) MIN
1/2" (13) FOAM
INSULATION IN
UNCONDITIONED
SPACE
2 − Intake and exhaust pipes should be placed as close
together as possible at termination end (refer to il-
lustrations). Maximum separation is 3" (76mm) on roof
terminations and 6" (152mm) on side wall termina-
tions.
12" (305) ABOVE
AVERAGE SNOW
ACCUMULATION
3" (76) OR
2" (51) PVC
3 − If necessary, install a field−provided reducer to adapt
larger vent pipe size to termination pipe size.
PROVIDE SUPPORT
FOR INTAKE AND
EXHAUST LINES
4 − On roof terminations, the intake piping should termi-
nate straight down using two 90° elbows (See figure
31).
DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
5 − Exhaust piping must terminate straight out or up as
shown. In rooftop applications, a reducer may be re-
quired on the exhaust piping at the point where it exits
the structure to improve the velocity of exhaust away
from the intake piping. See table 8.
FIGURE 31
12" (305) MAX.
(unless supported)
1/2" (13) ARMAFLEX
INSULATION IN
UNCONDITIONED SPACE
1/2" (13)
ARMAFLEX
INSULATION
NOTE − Care must be taken to avoid recirculation of
exhaust back into intake pipe.
FIELD−
PROVIDED
REDUCER MAY
BE REQUIRED
TO ADAPT
LARGER VENT
PIPE SIZE TO
TERMINATION
OUTSIDE
SIZE
TERMINA-
TION PIPE
PER TABLE
6 − On field supplied terminations for side wall exits, ex-
haust piping should extend a minimum of 12 inches
(305mm) beyond the outside wall. Intake piping
6" (152)
MAXI-
MUM
Inches (mm)
8" (203)
MINIMUM
WALL
2" (51)
PVC
7 − On field supplied terminations, a minimum separation
distance between the end of the exhaust pipe and the
end of the intake pipe is 8 inches (203mm).
COUPLING
TOP VIEW WALL RING KIT WITH STRAIGHT INTAKE
(15F74)
8 − If intake and exhaust piping must be run up a side wall
to position above snow accumulation or other obstruc-
tions, piping must be supported every 3 ft. (.9m) as
method. In addition, WTK wall termination kit must be
extended for use in this application. See figure 38.
When exhaust and intake piping must be run up an
outside wall, the exhaust piping is reduced to 1−1/2"
(38mm) after the final elbow. The intake piping may be
equipped with a 90° elbow turndown. Using turndown
will add 5 feet (1.5m) to the equivalent length of the
pipe.
1/2 (13) ARMAFLEX
12 (305) MAX.
INSULATION IN
UNCONDITIONED
SPACE
1/2" (13)
ARMAFLEX
INSULATION
FIELD−
PROVIDED
REDUCER MAY
BE REQUIRED
TO ADAPT
SIZE
TERMINATION PIPE
PER TABLE 8.
LARGER VENT
PIPE SIZE TO
TERMINATION
6 (152)
MAXIMUM
4 (102)
MINIMUM
Inches (mm)
OUTSIDE
WALL
9 − Based on the recommendation of the manufacturer, a
multiple furnace installation may use a group of up to
four termination kits WTK assembled together hori-
TOP VIEW WALL RING KIT WITH 90° ELBOW ON INTAKE
(15F74)
FIGURE 32
Page 28
Download from Www.Somanuals.com. All Manuals Search And Download.
EXHAUST VENT
EXHAUST
TERMINATION
12" (305) ABOVE
AVERAGE SNOW
ACCUMULATION
Inches (mm)
Front View
INTAKE
VENT
INTAKE
TERMINATION
1/2" (13) Foam Insulation
in Unconditioned Space
Side View
FIELD−PROVIDED
REDUCER MAY BE REQUIRED
TO ADAPT LARGER VENT
PIPE SIZE TO TERMINATION
FIELD−
PROVIDED
REDUCER MAY
BE REQUIRED
TO ADAPT
EXHAUST VENT
EXHAUST
INTAKE
LARGER VENT
PIPE SIZE TO
TERMINATION
DIRECT VENT CONCENTRIC ROOFTOP TERMINATION
(71M80, 69M29 or 60L46)
INTAKE VENT
OUTSIDE WALL
Inches (mm)
FIGURE 33
DIRECT VENT WALL TERMINATION KIT
(22G44, 44J40, 30G28 or 81J20)
INTAKE
Inches (mm)
TERMINATION
EXHAUST
TERMINATION
FIGURE 36
EXHAUST
12"
(305)
INTAKE
EXHAUST
VENT
12" (305) Min.
above grade or average
snow accumulation.
5"
(127)
5−1/2"
(140)
FIELD−PROVIDED
REDUCER MAY
INTAKE
VENT
BE REQUIRED TO
ADAPT LARGER
VENT PIPE SIZE
TO TERMINATION
18" MAX.
(457)
Front View
EXHAUST VENT
DIRECT VENT CONCENTRIC WALL TERMINATION
(71M80, 69M29 or 60L46)
Inches (mm)
FIGURE 34
INTAKE
VENT
Side View
12" (305) MAX. for 2" (51)
(unless supported)
Inches(mm)
UNCONDITIONED
SPACE
OPTIONAL VENT TERMINATION FOR MULTIPLE UNIT
INSTALLATION OF DIRECT VENT WALL TERMINATION KIT WTK
8 (203)
MIN.
OUTSIDE WALL
FIGURE 37
SIZE
TERMINATION
PROVIDE SUPPORT
FOR INTAKE AND
PIPE PER
EXHAUST LINES EVERY
36" (914)
12" (305) ABOVE
FIELD−PROVIDED
AVERAGE SNOW
REDUCER MAY
ACCUMULATION
BE REQUIRED TO
ADAPT LARGER
VENT PIPE SIZE
TO TERMINATION
1/2" (13) FOAM
INSULATION IN
UNCONDITIONED
SPACE
1/2" (13) FOAM
INSULATION
SIDE VIEW
DIRECT VENT WALL RING TERMINATION
(15F74)
FIGURE 35
Page 29
Download from Www.Somanuals.com. All Manuals Search And Download.
12" (305) MAX. for 2" (51)
20" (508) MAX. for 3" (76)
(unless supported)
Inches (mm)
EXHAUST
AIR
COVER EXHAUST
VENT WITH
1/2" (13)
12"
(305)
FOAM
INSULATION
8" (203)
INTAKE
AIR
INTAKE
AIR
Minimum
Minimum 12"
(305)
above grade or
average snow
accumulation.
EXHAUST
AIR
Minimum 12"
(305)
5"
(127)
above grade or
average snow
accumulation.
5-1/2"
(140)
GRADE
Side View
GRADE
Front View
DIRECT VENT TERMINATION
WALL TERMINATION KIT (22G44, 44J40, 30G28 or 81J20) EXTENDED VENT FOR GRADE CLEARANCE
FIGURE 38
G61MP DIRECT VENT APPLICATION
USING EX
STRAIGHT−CUT OR
ANGLE−CUT IN DIRECTION
OF ROOF SLOPE *
Inches(mm)
SIZE TERMINATION
PIPE PER TABLE 8.
12" (305mm)
ABOVE AVE.
SNOW
ACCUMULATION
3" − 8"
(76mm−
8" − 12"
EXHAUST VENT
1/2" (13mm)
WEATHERPROOF
INSULATION
203mm)
(203mm − 305mm)
SHOULDER OF FITTINGS
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
INTAKE PIPE
INSULATION (optional)
3" (76) OR
2" (51) PVC
SHEET
METAL TOP
PLATE
UNCONDITIONED
ATTIC SPACE
ALTERNATE
INTAKE PIPE
PROVIDE SUPPORT
FOR EXHAUST LINES
Minimum 12" (305)
above roof or average
snow accumulation.
3" − 8"
(76mm−
203mm)
INSULATE
TO FORM
SEAL
EXTERIOR
PORTION OF
CHIMNEY
*SIZE TERMINATION
PIPE PER TABLE 8.
NON−DIRECT VENT ROOF TERMINATION KIT
(15F75 or 44J41)
FIGURE 40
NOTE − Do not discharge exhaust gases directly into any chimney or vent stack. If ver-
tical discharge through an existing unused chimney or stack is required, insert piping
inside chimney until the pipe open end is above top of chimney and terminate as illus-
trated. In any exterior portion of chimney, the exhaust vent must be insulated.
FIGURE 39
Details of Exhaust Piping Terminations for Non-Direct
Vent Applications
12" (305) Max. for 2" (51)
Unless Supported
1/2" (13) ARMAFLEX
INSULATION IN
UNCONDITIONED SPACE
Exhaust pipes may be routed either horizontally through an
outside wall or vertically through the roof. In attic or closet
installations, vertical termination through the roof is pre-
1/2" (13)
ARMAFLEX
INSULATION
FIELD−PROVIDED
REDUCER MAY
BE REQUIRED TO
ADAPT LARGER
VENT PIPE SIZE
TO TERMINATION
1 − Exhaust piping must terminate straight out or up as
shown. The termination pipe must be sized as listed in
ity required to move the exhaust gases away from the
building.
PVC REDUCER
SIZE TERMINATION
PIPE PER TABLE 8.
Inches (mm)
TOP VIEW
NON−DIRECT VENT WALL RING KIT
(15F74)
2 − On field supplied terminations for side wall exits, ex-
haust piping should extend a maximum of 12 inches
(305mm) beyond the outside wall, unless support is
FIGURE 41
Page 30
Download from Www.Somanuals.com. All Manuals Search And Download.
3 − If exhaust piping must be run up a side wall to position
above snow accumulation or other obstructions, pip-
ing must be supported every 3 feet (.9m) as shown in
When exhaust piping must be run up an outside wall,
any reduction in exhaust pipe size must be done after
the final elbow.
sate trap should extend below the unit. A 5−1/2" service
clearance is required for the condensate trap. Refer to fig-
ure 44 for condensate trap locations.
CONDENSATE TRAP LOCATIONS
(Unit shown in upflow position)
Horizontal
left and
Horizontal
right and
optional
12" (305) Max. for 2" (51)
Unless Supported
Inches(mm)
optional
downflow
downflow
UNCONDITIONED
SPACE
OUTSIDE WALL
SIZE TER-
MINATION
PIPE PER
PROVIDE SUPPORT
FOR EXHAUST LINES
EVERY 36" (914)
12" (305) ABOVE
AVERAGE SNOW
ACCUMULATION
Optional
upflow
Optional
upflow
FIELD−PROVIDED
REDUCER MAY BE
REQUIRED TO
ADAPT LARGER
VENT PIPE SIZE TO
TERMINATION
1/2" (13) FOAM
INSULATION IN
UNCONDITIONED
SPACE
1/2" (13) FOAM
INSULATION
SIDE VIEW
NON−DIRECT VENT WALL RING TERMINATION
(15F74)
FIGURE 44
1 − Determine which side condensate piping will exit the
unit. Remove plugs from the condensate collar at the
appropriate location on the side of the unit.
FIGURE 42
G61MP NON−DIRECT VENT APPLICATION
USING EXISTING CHIMNEY
NOTE − The condensate trap is factory−shipped with
two rubber O−rings and two rubber clean−out caps
installed. Check to make sure that these items are in
place before installing the trap assembly.
STRAIGHT−CUT OR
ANGLE−CUT IN DIRECTION
OF ROOF SLOPE
SIZE TERMINATION
PIPE PER TABLE 8.
3" − 8"
(76mm−
203mm)
2 − Install condensate trap onto the condensate collar.
Use provided HI/LO screws to secure two upper
flanges of the trap to the collar. Use provided sheet
metal screw to secure bottom trap flange to side of
unit. DO NOT apply glue to secure condensate trap
to cabinet. All other joints must be glued. See figure
45.
EXHAUST VENT
1/2" (13mm)
WEATHERPROOF
INSULATION
MINIMUM12"
(305mm) ABOVE
AVERAGE SNOW
ACCUMULATION
SHOULDER OF FITTINGS
PROVIDE SUPPORT
OF PIPE ON TOP PLATE
SHEET
METAL TOP
PLATE
3" − 8"
(76mm−
203mm)
NOTE − In upflow and downflow applications, con-
densate trap must be installed on the same side as
exhaust piping.
INSULATE
TO FORM
SEAL
EXTERIOR
PORTION OF
CHIMNEY
CAUTION
NOTE − Do not discharge exhaust gases directly into any chimney or vent stack. If ver-
tical discharge through an existing unused chimney or stack is required, insert piping
inside chimney until the pipe open end is above top of chimney and terminate as illus-
trated. In any exterior portion of chimney, the exhaust vent must be insulated.
DO NOT use a power driver to tighten screws which
secure condensate trap to cabinet. Screws should
be hand−tightened using a screw driver to avoid the
possibility of damage to the trap assembly.
FIGURE 43
Condensate Piping
3 − The condensate trap provided with the unit is
manufactured using ABS material. Use ABS to PVC
transition solvent cement to glue a field−provided PVC
coupling or PVC pipe to the trap. Install a tee and vent
pipe near the trap.
This unit is designed for either right- or left-side exit of con-
densate piping in either upflow or downflow applications;
however, it must be installed on the same side of the unit as
the exhaust piping. In horizontal applications, the conden-
Page 31
Download from Www.Somanuals.com. All Manuals Search And Download.
NOTE − The condensate trap drain stubs (both sides)
have an outer diameter which will accept a standard
3/4" PVC coupling. The inner diameter of each stub
will accept standard 1/2" diameter PVC pipe.
5 − If unit will be started immediately upon completion of
installation, prime trap per procedure outlined in Unit
Start−Up section.
6 − Glue the provided cap onto the unused condensate
drain line stub.
NOTE − Vinyl tubing may be used for condensate
drain. Tubing must be 1−1/4" OD X 1" ID and should be
attached to the drain stubs on the trap using a hose
clamp.
CONDENSATE ASSEMBLY
4 − Glue the field−provided drain line to the tee. Route the
drain line to an open drain. As an alternate, clear vinyl
tubing may be used to drain condensate away from
the trap. Secure the vinyl tubing to the drain stubs on
the trap using a hose clamp. Do not overtighten the
hose clamp.
HI/LO SCREWS
(DO NOT use power
driver. Hand−tighten
using screw driver.)
VENT
NIPPLE
O−RINGS
Condensate line must be sloped downward away from
condensate trap to drain. If drain level is above con-
densate trap, condensate pump must be used. Con-
densate drain line should be routed within the condi-
tioned space to avoid freezing of condensate and
blockage of drain line. If this is not possible, a heat
cable kit may be used on the condensate trap and line.
Heating cable kit is available from Lennox in various
lengths; 6 ft. (1.8m) − kit no. 26K68; 24 ft. (7.3m) − kit
no. 26K69; and 50 ft. (15.2m) − kit no. 26K70.
TEE
CAP
NIPPLE
COUPLING
CLEAN−OUT ACCESS
(both sides)
CONDENSATE TRAP
SCREW
NOTE − Use screws to secure condensate trap to cabinet. DO
NOT apply glue to this joint. All other joints must be glued.
CAUTION
Do not use copper tubing or existing copper
condensate lines for drain line.
FIGURE 45
Page 32
Download from Www.Somanuals.com. All Manuals Search And Download.
Gas Piping
IMPORTANT
Compounds used on threaded joints of gas piping
must be resistant to the actions of liquified petro-
leum gases.
CAUTION
If a flexible gas connector is required or allowed by
the authority that has jurisdiction, black iron pipe
shall be installed at the gas valve and extend outside
the furnace cabinet.
MANUAL MAIN SHUT−OFF
VALVE WILL NOT HOLD
NORMAL TEST PRESSURE
FURNACE
ISOLATE
GAS VALVE
WARNING
Do not exceed 600 in−lbs (50 ft−lbs) torque when at-
taching the gas piping to the gas valve.
CAP
1 − Gas piping may be routed into the unit through either
the left- or right-hand side. Supply piping enters into
the gas valve from the side of the valve as shown in
FIGURE 46
Leak Check
After gas piping is completed, carefully check all piping
connections (factory− and field−installed) for gas leaks. Use
a leak detecting solution or other preferred means.
2 − When connecting gas supply, factors such as length of
run, number of fittings and furnace rating must be con-
recommended pipe sizes for typical applications.
The furnace must be isolated from the gas supply system
by closing its individual manual shut-off valve during any
pressure testing of the gas supply system at pressures less
than or equal to 1/2 psig (3.48 kPa, 14 inches w.c.).
NOTE − Use two wrenches when connecting gas pip-
ing to avoid transferring torque to the manifold.
3 − Gas piping must not run in or through air ducts, clothes
chutes, chimneys or gas vents, dumb waiters or eleva-
tor shafts. Center gas line through piping hole. Gas
IMPORTANT
When testing pressure of gas lines, gas valve must
valves can be damaged if subjected to pressures
greater than 1/2 psig (3.48 kPa).
4 − Piping should be sloped 1/4 inch per 15 feet (6mm per
5.6m) upward toward the gas meter from the furnace.
The piping must be supported at proper intervals, ev-
ery 8 to 10 feet (2.44 to 3.05m), using suitable hangers
or straps. Install a drip leg in vertical pipe runs to serve as
a trap for sediment or condensate.
WARNING
FIRE OR EXPLOSION HAZARD
5 − A 1/8" N.P.T. plugged tap or pressure post is located
on the gas valve to facilitate test gauge connection.
Failure to follow the safety warnings exactly could
result in serious injury, death, or property damage.
Never use an open flame to test for gas leaks. Check
all connections using a commercially available soap
solution made specifically for leak detection.Some
soaps used for leak detection are corrosive to certain
metals. Carefully rinse piping thoroughly after leak
test has been completed.
6 − In some localities, codes may require installation of a
manual main shut-off valve and union (furnished by in-
staller) external to the unit. Union must be of the
ground joint type.
Upflow Application
Left Side Piping
(Standard)
Upflow Application
Right Side Piping
(Alternate)
AUTOMATIC
GAS VALVE
(with manual
shut−off valve)
MANUAL
MAIN SHUT−OFF
VALVE
MANUAL
MAIN SHUT−OFF
VALVE
GROUND
JOINT
UNION
GROUND
JOINT
UNION
DRIP LEG
FIELD
PROVIDED
AND INSTALLED
DRIP LEG
FIGURE 47
Page 33
Download from Www.Somanuals.com. All Manuals Search And Download.
Horizontal Applications
Possible Gas Piping Configerations
MANUAL
MAIN SHUT−OFF
VALVE
Horizontal Application
Left−Side Air Discharge
MANUAL
MAIN SHUT−OFF
VALVE
GROUND
JOINT
UNION
GROUND
JOINT
UNION
DRIP LEG
DRIP LEG
MANUAL
MAIN SHUT−OFF
VALVE
(With 1/8 in. NPT
Plugged Tap
Shown)
Horizontal Application
Right−Side Air Discharge
GROUND
JOINT
UNION
DRIP LEG
FIGURE 48
TABLE 9
GAS PIPE CAPACITY − FT3/HR (kL/HR)
Length of Pipe−Feet(m)
Nominal
Iron Pipe Size
−Inches(mm)
Internal
Diameter
−Inches(mm)
10
(3.048)
20
(6.096)
30
(9.144)
40
50
60
70
80
90
(12.192) (15.240) (18.288) (21.336) (24.384) (27.432) (30.480)
100
1/4
(6.35)
.364
(9.246)
43
(1.13)
29
(.82)
24
(.68)
20
(.57)
18
(.51)
16
(.45)
15
(.42)
14
(.40)
13
(.37)
12
(.34)
3/8
(9.53)
.493
(12.522)
95
(2.69)
65
(1.84)
52
(1.47)
45
(1.27)
40
(1.13)
36
(1.02)
33
(.73)
31
(.88)
29
(.82)
27
(.76)
1/2
(12.7)
.622
(17.799)
175
(4.96)
120
(3.40)
97
(2.75)
82
(2.32)
73
(2.07)
66
(1.87)
61
(1.73)
57
(1.61)
53
(1.50)
50
(1.42)
3/4
(19.05)
.824
(20.930)
360
(10.19)
250
(7.08)
200
(5.66)
170
(4.81)
151
(4.28)
138
(3.91)
125
(3.54)
118
(3.34)
110
(3.11)
103
(2.92)
1
(25.4)
1.049
(26.645)
680
(19.25)
465
(13.17)
375
(10.62)
320
(9.06)
285
(8.07)
260
(7.36)
240
(6.80)
220
(6.23)
205
(5.80)
195
(5.52)
1−1/4
(31.75)
1.380
(35.052)
1400
(39.64)
950
(26.90)
770
(21.80)
660
(18.69)
580
(16.42)
530
(15.01)
490
(13.87)
460
(13.03)
430
(12.18)
400
(11.33)
1−1/2
(38.1)
1.610
(40.894)
2100
(59.46)
460
(41.34)
1180
(33.41)
990
(28.03)
900
(25.48)
810
(22.94)
750
(21.24)
690
(19.54)
650
(18.41)
620
(17.56)
2
(50.8)
2.067
(52.502)
3950
(111.85)
2750
(77.87)
2200
(62.30)
1900
(53.80)
1680
(47.57)
1520
(43.04)
1400
(39.64)
1300
(36.81)
1220
(34.55)
1150
(32.56)
2−1/2
(63.5)
2.469
(67.713)
6300
(178.39)
4350
(123.17)
3520
(99.67)
3000
(84.95)
2650
(75.04)
2400
(67.96)
2250
(63.71)
2050
(58.05)
1950
(55.22)
1850
(52.38)
3
(76.2)
3.068
(77.927)
11000
(311.48)
7700
(218.03)
6250
(176.98)
5300
(150.07)
4750
(134.50)
4300
(121.76)
3900
(110.43)
3700
(104.77)
3450
(97.69)
3250
(92.03)
4
(101.6)
4.026
(102.260)
23000
(651.27)
15800
(447.39)
12800
(362.44)
10900
(308.64)
9700
(274.67)
8800
(249.18)
8100
(229.36)
7500
(212.37)
7200
(203.88)
6700
(189.72)
NOTE − Capacity given in cubic feet of gas per hour (kilo liters of gas per hour) and based on 0.60 specific gravity gas.
Page 34
Download from Www.Somanuals.com. All Manuals Search And Download.
The unit is equipped with a field make−up box. The make−
up box may be moved to the right side of the furnace to fa-
cilitate installation. If the make−up box is moved to the right
side, the excess wire must be pulled into the blower
compartment. Secure the excess wire to the existing har-
ness to protect it from damage.
Electrical
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
for schematic wiring diagram and troubleshooting.
Electrostatic discharge can affect electronic com-
ponents. Take precautions during furnace installa-
tion and service to protect the furnace’s electronic
controls. Precautions will help to avoid control ex-
posure to electrostatic discharge by putting the fur-
nace, the control and the technician at the same
electrostatic potential. Neutralize electrostatic
charge by touching hand and all tools on an un-
painted unit surface, such as the gas valve or blower
deck, before performing any service procedure.
1 − Select circuit protection and wire size according to the
unit nameplate. The power supply wiring must meet
Class I restrictions.
2 − Holes are on both sides of the furnace cabinet to facili-
tate wiring.
3 − Install a separate disconnect switch (protected by ei-
ther fuse or circuit breaker) near the furnace so that
power can be turned off for servicing.
4 − Before connecting the thermostat or the power wiring,
check to make sure the wires will be long enough for
servicing at a later date. Remove the blower access
panel to check the length of the wire.
INTERIOR MAKE−UP BOX INSTALLATION
MAKE−UP
BOX
5 − Complete the wiring connections to the equipment.
Use the provided unit wiring diagram and the field wir-
18−gauge wire or larger that is suitable for Class II rat-
ing for thermostat connections.
Right Side
NOTE − Do NOT make a wire connection between
the room thermostat L terminal and the L terminal
of the G61MP integrated control.
6 − Electrically ground the unit according to local codes or,
in the absence of local codes, according to the current
National Electric Code (ANSI/NFPA No. 70) for the
USA and current Canadian Electric Code part 1 (CSA
standard C22.1) for Canada. A green ground wire is
provided in the field make−up box.
FIGURE 49
INTERIOR MAKE−UP BOX INSTALLATION
NOTE − The G61MP furnace contains electronic com-
ponents that are polarity sensitive. Make sure that the
furnace is wired correctly and is properly grounded.
Left side
MAKE−UP
BOX
7 − One line voltage ꢁHUM" 1/4" spade terminal is provided
on the furnace control board. Any humidifier rated up
to one amp can be connected to this terminal with the
neutral leg of the circuit being connected to one of the
board configuration. This terminal is energized in the
heating mode when the combustion air inducer is oper-
ating.
8 − One line voltage ꢁEAC" 1/4" spade terminal is provided
on the furnace control board. Any electronic air cleaner
rated up to one amp can be connected to this terminal
with the neutral leg of the circuit being connected to
control board configuration. This terminal is energized
when the indoor blower is operating.
FIGURE 50
Page 35
Download from Www.Somanuals.com. All Manuals Search And Download.
9 − One 24V ꢁH" terminal is provided on the furnace control
board terminal block. Any humidifier rated up to 0.5
amp can be connected to this terminal with the ground
leg of the circuit being connected to either ground or
uration.
Indoor Blower Speeds
1 − When the thermostat is set to ꢁFAN ON," the indoor
blower will run continuously on the low heat speed
when there is no cooling or heating demand.
2 − When the G61MP is operating in the high−fire or low−
fire heating mode, the indoor blower will run on the cor-
responding heating speed.
10 −Install the room thermostat according to the instruc-
field wiring connections in varying applications. If the
furnace is being matched with a heat pump, refer to the
instruction packaged with the dual fuel thermostat.
3 − When there is a cooling demand, the indoor blower will
run on the corresponding cooling speed.
TYPICAL G61MP FIELD WIRING DIAGRAM
FIGURE 51
Page 36
Download from Www.Somanuals.com. All Manuals Search And Download.
TABLE 10
Field Wiring Applications
DIP Switch Settings and On−Board Links
W915
W951
Thermostat
Wiring Connections
(Y1 to Y2)
Two−Stage
Cooling
DIP Switch 1
(O to R)
Heat Pumps
1 Heat / 1 Cool
ON
Intact
Intact
S1
T’STAT
CONTROL
TERM. STRIP
OUTDOOR
UNIT
NOTE − Use DIP
switch 2 to set sec-
ond−stage heat ON
delay.
OFF10 minutes.
ON−15 minutes.
EXISTING
W915 JUMPER
1 Heat / 2 Cool
ON
Cut
Intact
S1
T’STAT
CONTROL
TERM. STRIP
OUTDOOR
UNIT
NOTE − Use DIP
switch 2 to set sec-
ond−stage heat ON
delay.
OFF−10 minutes.
ON−15 minutes.
Page 37
Download from Www.Somanuals.com. All Manuals Search And Download.
TABLE 10
Field Wiring Applications (Continued)
DIP Switch Settings and On−Board Links
W915
W951
Thermostat
Wiring Connections
(Y1 to Y2)
Two−Stage
Cooling
DIP Switch 1
(O to R)
Heat Pumps
2 Heat / 2 Cool
OFF
Cut
Intact
S1
T’STAT
CONTROL
TERM. STRIP
OUTDOOR
UNIT
2 Heat / 1 Cool
OFF
Intact
Intact
S1
T’STAT
CONTROL
TERM. STRIP
OUTDOOR
UNIT
EXISTING
W915 JUMPER
NOTE − Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the G61MP
integrated control.
Page 38
Download from Www.Somanuals.com. All Manuals Search And Download.
TWO−STAGE INTEGRATED CONTROL BOARD
1/4" QUICK CONNECT TERMINALS
SENSE = 120 VAC OUTPUT TO FLAME SENSER
NEUTRALS= 120 VAC NEUTRAL
PARK = DEAD TERMINAL FOR UNUSED BLOWER LEAD
HEAT LOW = 120 VAC OUTPUT TO CIRC BLWR −− LOW HT SPEED
AND CONTINUOUS FAN
HEAT HIGH/ COOL LOW = 120 VAC OUTPUT TO CIRC BLWR −−
HIGH HEAT AND LOW COOL SPEED
COOL HIGH = 120 VAC OUTPUT TO CIRC BLWR −− HIGH COOL SPEED
DIAGNOSTIC
LEDs
THERMOSTAT CONNECTIONS (TB1)
DIP
SWITCHES
ON−BOARD
JUMPERS
1= ERROR CODE RECALL
H= 24V HUMIDIFIER OUTPUT
L= DO NOT USE
DIP SWITCH FUNCTIONS
W915
W951
DIP SWITCH(ES)
FUNCTION
1 −− 2 Stage T’stat
2 −− 2nd Stage Delay
3 & 4 −− Heat Off Delay
5 −− Cool Off Delay
Selects t/stat type (single or two−stage)
Second stage ON delay (single−stage t’stat)
Heating fan OFF delay
Cooling fan OFF delay
FIGURE 52
Page 39
Download from Www.Somanuals.com. All Manuals Search And Download.
TABLE 11
Heating Blower−Off Delay Switch Settings
Integrated Control Board
G61MP units are equipped with a two−stage integrated
control. This control manages ignition timing and fan off
delays based on selections made using the control DIP
switches and jumpers. The control includes an internal
watchguard feature which automatically resets the ignition
control when it has been locked out. After one hour of con-
tinuous thermostat demand for heat, the watchguard will
break and remake thermostat demand to the furnace and
automatically reset the control to relight the furnace.
Blower Off Delay
(Seconds)
60
Switch 3
Switch 4
Off
Off
On
On
On
Off
Off
On
90
120
180
Switch 5 −− Cooling Blower−Off Delay −− The cooling
blower−off delay (time that the blower operates after the
cooling demand has been satisfied) can be adjusted by
moving switch 5 on the integrated control board. The
switch is factory−set in the OFF position, which provides a
cooling blower−off delay of 45 seconds. If the switch is
toggled to the ON position, it will provide a 2−second cool-
ing blower−off delay
Switch 1 −− Thermostat Selection −−This unit may be used
with either a single−stage or two−stage thermostat. The
thermostat selection is made using a DIP switch which
must be properly positioned for the particular application.
The DIP switch is factory−positioned for use with a two−
stage thermostat. If a single−stage thermostat is to be used,
the DIP switch must be repositioned.
On−board jumper W951, which connects terminals R and O
on the integrated control board, must be cut when the fur-
nace is installed in applications which include a heat pump
unit and a thermostat which features dual fuel use. If the
jumper is left intact, terminal ꢁO" will remain energized elim-
inating the HEAT MODE in the heat pump.
a − Select ꢁOFF" for two−stage heating operation con-
trolled by a two−stage heating thermostat (factory set-
ting);
b − Select ꢁON" for two−stage heating operation con-
trolled by a single−stage heating thermostat. This set-
ting provides a timed delay before second−stage heat
is initiated.
On−board jumper W915, which connects terminals Y1 and
Y2 on the integrated control board, must be cut if two−stage
cooling will be used. If the jumper is not cut the outdoor unit
will operate in first−stage cooling only.
Switch 2 −− Second Stage Delay (Used with Single−
Stage Thermostat Only) −− This switch is used to deter-
mine the second stage on delay when a single−stage ther-
mostat is being used. The switch is factory−set in the OFF
position, which provides a 10−minute delay before second−
stage heat is initiated. If the switch is toggled to the ON
position, it will provide a 15−minute delay before second−
stage heat is initiated. This switch is only activated when
the thermostat selector jumper is positioned for SINGLE−
stage thermostat use.
Unit Start−Up
FOR YOUR SAFETY READ BEFORE OPERATING
WARNING
Do not use this furnace if any part has been under-
water. A flood−damaged furnace is extremely dan-
gerous. Attempts to use the furnace can result in
fire or explosion. Immediately call a qualified ser-
vice technician to inspect the furnace and to replace
all gas controls, control system parts, and electrical
parts that have been wet or to replace the furnace,
if deemed necessary.
Switches 3 and 4 −− Heating Blower−Off Delay −− The
heating blower−on delay of 45 seconds is not adjustable.
The heating blower−off delay (time that the blower operates
after the heating demand has been satisfied) can be ad-
justed by moving switches 3 and 4 on the integrated control
board. The unit is shipped from the factory with a heating
blower−off delay of 90 seconds. The heating blower off
delay affects comfort and is adjustable to satisfy individual
applications. Adjust the blower off delay to achieve a sup-
ply air temperature between 90° and 110°F at the exact
moment that the blower is de−energized. Longer off delay
settings provide lower supply air temperatures; shorter set-
vides the blower off timings that will result from different
switch settings.
WARNING
Danger of explosion. Can cause injury
or product or property damage. Should
the gas supply fail to shut off or if
overheating occurs, shut off the gas
valve to the furnace before shutting off
the electrical supply.
Page 42
Download from Www.Somanuals.com. All Manuals Search And Download.
4 − This furnace is equipped with an ignition device which
automatically lights the burners. Do not try to light the
burners by hand.
CAUTION
Before attempting to perform any service or mainte-
nance, turn the electrical power to unit OFF at dis-
connect switch.
5 − Remove the upper access panel.
6 − White Rodgers 36E Gas Valve − Move gas valve
36E valve.
Priming Condensate Trap
Honeywell VR8205 Gas Valve − Move switch on gas
The condensate trap should be primed with water prior to
start−up to ensure proper condensate drainage. Either
pour 10 fl. oz. (300 ml) of water into the trap, or follow
these steps to prime the trap:
valve clockwise
56.
to OFF. Do not force. See figure
7 − Wait five minutes to clear out any gas. If you then smell
gas, STOP! Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s instruc-
tions. If you do not smell gas go to next step.
1 − Follow the lighting instructions to place the unit into op-
eration.
2 − Set the thermostat to initiate a heating demand.
WHITE RODGERS 36E SERIES GAS VALVE
3 − Allow the burners to fire for approximately 3 minutes.
4 − Adjust the thermostat to deactivate the heating de-
mand.
HIGH FIRE
MANIFOLD
PRESSURE
ADJUSTMENT
ON SIDE
5 − Wait for the combustion air inducer to stop. Set the
thermostat to initiate a heating demand and again al-
low the burners to fire for approximately 3 minutes.
(under cap)
6 − Adjust the thermostat to deactivate the heating de-
mand and again wait for the combustion air inducer to
stop. At this point, the trap should be primed with suffi-
cient water to ensure proper condensate drain opera-
tion.
MANIFOLD
PRESSURE
TAP ON SIDE
LOW FIRE MANIFOLD
PRESSURE ADJUSTMENT
ON SIDE (under cap)
INLET PRESSURE
TAP ON SIDE
BEFORE LIGHTING the unit, smell all around the fur-
nace area for gas. Be sure to smell next to the floor be-
cause some gas is heavier than air and will settle on the
floor.
GAS VALVE SHOWN IN OFF POSITION
FIGURE 55
HONEYWELL VR8205 SERIES GAS VALVE
HIGH FIRE
ADJUSTING SCREW
(under cap)
The gas valve on the G61MP will be be equipped with a
gas control switch (lever). Use only your hand to move
the switch. Never use tools. If the the switch will not move
by hand, do not try to repair it. Force or attempted repair
may result in a fire or explosion.
MANIFOLD
PRESSURE
TAP
Placing the furnace into operation:
G61MP units are equipped with an automatic ignition
system. Do not attempt to manually light burners on this
furnace. Each time the thermostat calls for heat, the
burners will automatically light. The ignitor does not get
hot when there is no call for heat on units with this ignition
system.
LOW FIRE
ADJUSTING SCREW
(under cap)
INLET PRESSURE TAP
GAS VALVE SHOWN IN OFF POSITION
FIGURE 56
8 − White Rodgers 36E Gas Valve − Move gas valve switch
valve.
WARNING
If you do not follow these instructions exactly, a fire
or explosion may result causing property damage,
personal injury or death.
Honeywell VR8205 Gas Valve − Move switch on gas
valve counterclockwise
to ON. Do not force.
9 − Replace the upper access panel.
1 − STOP! Read the safety information at the beginning of
10− Turn on all electrical power to to the unit.
11− Set the thermostat to desired setting.
this section.
2 − Set the thermostat to the lowest setting.
3 − Turn off all electrical power to the unit.
NOTE − When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas line.
Page 43
Download from Www.Somanuals.com. All Manuals Search And Download.
12− If the appliance will not operate, follow the instructions
ꢁTurning Off Gas to Unit" and call your service techni-
cian or gas supplier.
2 − Tee into the gas valve regulator vent hose and connect
test gauge ꢁ−" connection.
TABLE 12
Turning Off Gas to Unit
3
Gas Flow Rate (Ft. /Hr.)
1 − Set the thermostat to the lowest setting.
Gas Meter Size
1/2 cu ft Dial
Seconds for 1
Revolution
1 cu ft Dial
360
300
257
225
200
180
164
150
138
129
120
113
106
100
95
2 − Turn off all electrical power to the unit if service is to be
performed.
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
180
150
129
113
100
90
82
75
69
64
60
56
53
50
47
45
43
41
39
38
36
35
33
32
31
30
3 − Remove the upper access panel.
4 − White Rodgers 36E Gas Valve − Move gas valve
switch to OFF.
Honeywell VR8205 Gas Valve − Move switch on gas
valve clockwise
to OFF. Do not force.
5 − Replace the upper access panel.
Gas Pressure Adjustment
Gas Flow (Approximate)
1 − Operate unit at least 15 minutes before checking gas
flow. Determine the time in seconds for one revolu-
tions of gas through the meter. A portable LP gas me-
ter (17Y44) is available for LP applications.
90
86
2 − Compare the number of seconds and the gas meter
the gas flow rate by the heating value to determine the
unit input rate. If manifold pressure is correct and the
unit input rate is incorrect, check gas orifices for proper
size and restriction.
82
78
75
72
69
67
3 − Remove temporary gas meter if installed.
64
NOTE − To obtain accurate reading, shut off all other gas
62
60
appliances connected to meter.
Supply Pressure Measurement
3 − Start unit on low heat (68% rate) and allow 5 minutes
for unit to reach steady state.
A threaded plug on the inlet side of the gas valve provides
access to the supply pressure tap. Remove the threaded
plug, install a field−provided barbed fitting and connect a
manometer to measure supply pressure. Replace the
threaded plug after measurements have been taken.
4 − While waiting for the unit to stabilize, notice the flame.
Flame should be stable and should not lift from burner.
Natural gas should burn blue.
5 − After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in table
13.
Manifold Pressure Measurement
To correctly measure manifold pressure, the differential
pressure between the positive gas manifold and the nega-
tive burner box must be considered. Use pressure test
adapter kit (available as Lennox part 10L34) to assist in
measurement.
6 − Repeat steps 3, 4 and 5 on high heat.
NOTE − Shut unit off and remove manometer as soon as an
accurate reading has been obtained. Take care to remove
barbed fitting and replace threaded plug.
1 − Remove the threaded plug from the outlet side of the
gas valve and install a field−provided barbed fitting.
Connect test gauge ꢁ+" connection to barbed fitting to
measure manifold pressure.
CAUTION
Do not attempt to make adjustments to the gas valve.
Page 44
Download from Www.Somanuals.com. All Manuals Search And Download.
TABLE 13
Manifold Pressure (Outlet) inches w.c.
Altitude (feet)
0−2000
2001−4500
4501−5500
5501−6500
6501−7500
7501−10000
Model Number
Fuel
Low High
Fire Fire
Low High
Fire Fiire
Low High
Fire Fiire
Low High
Fire Fiire
Low High
Fire Fiire
Low High
Fire Fiire
Natural
1.7
3.5
1.7
4.9
1.7
4.9
3.5
1.7
4.9
1.7
4.9
3.5
1.7
4.9
1.7
4.9
3.5
1.7
4.9
1.7
4.9
3.5
1.7
4.9
1.7
4.9
3.5
045, 070, 090, 110,
135
Propane 4.9
Natural 1.7
Propane 4.9
10.0
3.5
10.0
3.4
10.0
3.3
10.0
3.2
10.0
3.1
10.0
3.5
071, 091, 111
10.0
10.0
10.0
10.0
10.0
10.0
High Altitude Information
NOTE − In Canada, certification for installations at eleva-
tions over 4500 feet (1372 m) is the jurisdiction of local au-
thorities.
The combustion air pressure switches are factory−set and
require no adjustment.
NOTE − A natural to L.P. propane gas changeover kit is nec-
essary to convert this unit. Refer to the changeover kit
installation instruction for the conversion procedure.
The manifold pressure may require adjustment to ensure
proper manifold pressure settings at varying altitudes.
conversion kits at varying altitudes.
TABLE 14
Conversion Kit Requirements
High Altitude
Orifice Kit
Natural Gas
Only
High Altitude Pressure Switch Kit
ORDER TWO EACH
LPG/Propane Kit
LPG/Propane to
Natural Gas Kit
Input
1
7501−10,000 ft. 2000−4500 ft. 4501−7500 ft. 7501−10,000 ft. 0−7500 ft. 7501−10,000 ft. 0−7500 ft.
7501−10,000 ft.
44W49 + 44W51
44W49 + 44W51
44W49 + 47M82
44W49 + 44W51
44W49 + 47M82
44W49 + 44W51
44W49 + 47M82
44W49 + 44W51
−045
−070
−071
−090
−091
−110
−111
−135
44W51
44W51
47M82
44W51
47M82
44W51
47M82
44W51
− − −
− − −
− − −
− − −
44W48
44W48
44W48
44W48
44W48
44W48
44W48
44W48
44W50
44W50
44W50
44W50
44W50
44W50
44W50
44W50
44W49
44W49
44W49
44W49
44W49
44W49
44W49
44W49
− − −
56M06
26W83
56M21
26W86
75M22
56M23
56M93
24W49
− − −
24W49
75M22
26W85
− − −
26W85
− − −
56M22
− − −
56M22
56M93
1
High Altitude Orifice Kit is required and must be ordered separately for applications from 7501 to 10,000 ft.
Page 45
Download from Www.Somanuals.com. All Manuals Search And Download.
Testing for Proper Venting and Sufficient Combustion Air for Non−Direct Vent Applications
sufficient combustion/make-up air must be provided.
The venting system should be re-sized to approach
the minimum size as determined by using the ap-
propriate tables in appendix G in the current standards
WARNING
CARBON MONOXIDE POISONING HAZARD!
of the National Fuel Gas Code ANSI−Z223.1/NPFA 54
in the U.S.A., and the appropriate Natural Gas and
Propane appliances venting sizing tables in the cur-
rent standard of the CSA−B149 Natural Gas and Pro-
pane Installation Codes in Canada.
Failure to follow the steps outlined below for each
appliance connected to the venting system being
placed into operation could result in carbon monox-
ide poisoning or death.
The following steps shall be followed for each ap-
pliance connected to the venting system being
placed into operation, while all other appliances con-
nected to the venting system are not in operation.
9 − After determining that each appliance remaining
connected to the common venting system properly
vents when tested as indicated in step 3, return
doors, windows, exhaust fans, fireplace dampers
and any other gas-burning appliance to their previous
condition of use.
After the G61MP gas furnace has been started, the follow-
ing test should be conducted to ensure proper venting and
sufficient combustion air has been provided to the G61MP,
as well as to other gas-fired appliances which are separate-
ly vented.
Other Unit Adjustments
Primary and Secondary Limits
If a G61MP furnace replaces a Category I furnace which
was commonly vented with another gas appliance, the size
of the existing vent pipe for that gas appliance must be
checked. Without the heat of the original furnace flue prod-
ucts, the existing vent pipe is probably oversized for the
single water heater or other appliance. The vent should be
checked for proper draw with the remaining appliance.
The primary limit is located on the heating compartment
vestibule panel. The secondary limits are located in the
blower compartment, attached to the back side of the blow-
er. These limits are factory set and require no adjustment.
Flame Rollout Switches (Two)
These manually reset switches are located on the burner
box. If tripped, check for adequate combustion air before
resetting.
The test should be conducted while all appliances (both in
operation and those not in operation) are connected to the
venting system being tested. If the venting system has
been installed improperly, or if provisions have not been
made for sufficient amounts of combustion air, corrections
must be made as outlined in the previous section.
Pressure Switches (Two or Four)
The pressure switches are located in the heating compart-
ment on the combustion air inducer. These switches check
for proper combustion air inducer operation before allow-
ing ignition trial. The switches are factory−set and require
no adjustment.
1 − Seal any unused openings in the venting system.
2 − Visually inspect the venting system for proper size and
horizontal pitch. Determine there is no blockage or re-
striction, leakage, corrosion, or other deficiencies
which could cause an unsafe condition.
Back−Up Secondary Limit (090, 110 & 135 Models)
The back−up secondary limit is located on the combustion
air inducer. This switch protects the plastic components
from overheating due to indoor blower motor failure. If
tripped, check for proper blower operation before resetting.
3 − To the extent that it is practical, close all building doors
and windows and all doors between the space in which
the appliances connected to the venting system are lo-
cated and other spaces of the building.
Temperature Rise
After the furnace has been started and supply and return air
temperatures have been allowed to stabilize, check the
temperature rise. If necessary, adjust the blower speed to
maintain the temperature rise within the range shown on
the unit nameplate. Increase the blower speed to decrease
the temperature. Decrease the blower speed to increase
the temperature rise. Failure to do adjust the temperature
rise may cause erratic limit operation.
4 − Close fireplace dampers.
5 − Turn on clothes dryers and any appliances not con-
nected to the venting system. Turn on any exhaust
fans, such as range hoods and bathroom exhausts, so
they will operate at maximum speed. Do not operate a
summer exhaust fan.
6 − Follow the lighting instruction to place the appliance
being inspected into operation. Adjust thermostat so
appliance will operate continuously.
Thermostat Heat Anticipation
Set the heat anticipator setting (if adjustable) according to
the amp draw listed on the wiring diagram that is attached
to the unit.
7 − Use the flame of match or candle to test for spillage of
flue gases at the draft hood relief opening after 5 min-
utes of main burner operation.
Electrical
8 − If improper venting is observed during any of the
above tests, the venting system must be corrected or
1 − Check all wiring for loose connections.
Page 46
Download from Www.Somanuals.com. All Manuals Search And Download.
2 − Check for the correct voltage at the furnace (furnace
operating).
sure. After one hour of continuous thermostat demand for
heat, the Watchguard will break and remake thermostat de-
mand to the furnace and automatically reset the control to
begin the ignition sequence.
3 − Check amp-draw on the blower motor.
Motor Nameplate__________Actual__________
NOTE − Do not secure the electrical conduit directly to the
air ducts or structure.
Exhaust and Air Intake Pipe
1 − Check exhaust and air intake connections for tightness
and to make sure there is no blockage.
Blower Speeds
NOTE − CFM readings are taken external to unit with a dry
evaporator coil and without accessories.
1 − Turn off electrical power to furnace.
2 − Remove blower access panel.
2 − Are pressure switches closed? Obstructed exhaust
pipe will cause unit to shut off at pressure switches.
Check termination for blockages.
3 − Reset manual flame rollout switches on burner box
cover.
3 − Disconnect existing speed tap at control board speed
terminal.
Failure To Operate
NOTE − Termination of any unused motor leads must be
insulated.
If the unit fails to operate, check the following:
1 − Is the thermostat calling for heat?
2 − Are access panels securely in place?
3 − Is the main disconnect switch closed?
4 − Is there a blown fuse?
4 − Refer to blower speed selection chart on unit wiring dia-
gram for desired heating or cooling speed. See blower
5 − Connect selected speed tap at control board speed
terminal.
5 − Is the filter dirty or plugged? Dirty or plugged filters will
cause the limit control to shut the unit off.
6 − Resecure blower access panel.
7 − Turn on electrical power to furnace.
Electronic Ignition
6 − Is gas turned on at the meter?
7 − Is the manual main shut-off valve open?
8 − Is the internal manual shut-off valve open?
The integrated control has an added feature of an internal
Watchguard control. The feature serves as an automatic re-
set device for ignition control lockout caused by ignition fail-
ure. This type of lockout is usually due to low gas line pres-
9 − Is the unit ignition system in lock out? If the unit locks out
again, inspect the unit for blockages.
Page 47
Download from Www.Somanuals.com. All Manuals Search And Download.
Blower Performance Data
G61MP−36B−045 PERFORMANCE (Less Filter)
G61MP−48C−090 PERFORMANCE (Less Filter)
Air Volume / Watts at Different Blower Speeds
External
Air Volume / Watts at Different Blower Speeds
External
Medium−
High
Medium−
Low
Medium−
High
Medium−
Low
Static
Pressure
in. w.g.
Static
Pressure
in. w.g.
High
Low
High
Low
cfm Watts cfm Watts cfm Watts cfm Watts
1555 630 1410 585 1190 520 1030 435
1515 605 1385 555 1190 485 1020 415
1470 580 1345 520 1170 455 1010 400
1410 555 1310 495 1155 440 1000 385
1350 535 1250 465 1120 410 980 360
1290 505 1205 450 1080 390 950 345
1220 485 1145 420 1020 365 905 320
1145 460 1080 400 975 345 860 300
1050 425 985 365 870 320 785 285
945 410 900 345 825 305 730 270
cfm Watts cfm Watts cfm Watts cfm Watts
2180 930 1835 790 1520 630 1280 510
2135 885 1825 750 1510 610 1275 495
2085 840 1810 720 1505 580 1270 475
2030 800 1775 685 1500 565 1265 460
1940 760 1735 650 1480 535 1250 440
1865 725 1660 600 1430 505 1215 425
1740 670 1590 575 1380 475 1175 410
1645 640 1475 520 1290 450 1105 375
1540 600 1340 465 1175 405 1020 355
1335 540 1170 440 1070 375 950 330
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
Air volume based on bottom air return air. Actual air volume may vary on side return air applications.
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
Air volume based on bottom air return air. Actual air volume may vary on side return air applications.
G61MP−48C−110 PERFORMANCE (Less Filter)
G61MP−36B−070 PERFORMANCE (Less Filter)
Air Volume / Watts at Different Blower Speeds
External
Air Volume / Watts at Different Blower Speeds
External
Medium−
High
Medium−
Low
Static
Pressure
in. w.g.
Medium−
High
Medium−
Low
Static
Pressure
in. w.g.
High
Low
High
Low
cfm Watts cfm Watts cfm Watts cfm Watts
2160 880 1880 755 1490 602 1235 485
2100 850 1855 730 1480 585 1230 475
2035 805 1815 690 1475 560 1225 460
1965 750 1755 650 1475 545 1220 445
1885 725 1715 625 1465 510 1215 430
1780 680 1630 580 1420 490 1150 400
1690 660 1550 550 1360 460 1110 380
1575 620 1410 505 1210 405 1035 350
1375 550 1230 450 1125 380 970 325
1225 520 1120 415 1050 365 885 310
cfm Watts cfm Watts cfm Watts cfm Watts
1640 660 1415 575 1160 485 1005 410
1600 635 1395 550 1160 460 1000 385
1540 605 1370 525 1160 445 995 375
1495 580 1345 505 1145 425 990 365
1420 545 1275 480 1125 395 965 345
1360 525 1245 450 1080 375 945 325
1275 490 1165 410 1025 350 900 305
1170 465 1085 385 965 335 860 295
1080 440 1010 360 865 310 775 270
945 400 840 320 765 275 710 245
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
Air volume based on bottom air return air. Actual air volume may vary on side return air applications.
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
Air volume based on bottom air return air. Actual air volume may vary on side return air applications.
G61MP−36B−071 PERFORMANCE (Less Filter)
Air Volume / Watts at Different Blower Speeds
External
Medium−
High
Medium−
Low
Static
Pressure
in. w.g.
High
Low
cfm Watts cfm Watts cfm Watts cfm Watts
1460 620 1215 570 965 445 785 375
1420 590 1215 545 990 425 815 365
1365 550 1195 505 980 410 810 350
1325 525 1170 490 980 390 820 335
1255 495 1155 455 945 365 795 320
1190 465 1080 425 915 345 785 305
1120 440 1050 395 865 320 755 285
1035 410 975 365 790 295 695 255
900 375 865 330 715 275 615 235
795 350 745 300 600 245 510 215
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
Air volume based on bottom air return air. Actual air volume may vary on side return air applications.
Page 48
Download from Www.Somanuals.com. All Manuals Search And Download.
G61MP−60C−090 PERFORMANCE (Less Filter)
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional RAB Single Side Return Air − Air volumes in bold require field
Return Air Base, Return Air from Both Sides or Return fabricated transition to accommodate 20 x 25 x 1 in. air
External
Static
Air from Bottom and One Side.
filter in order to maintain proper air velocity.
Pressure
in. w.g.
Medium−
High
Medium−
Low
Medium−
High
Medium−
Low
High
Low
High
Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
2840 1450 2345 1105 1895 900 1515 700 2835 1495 2340 1155 1800 895 1440 695
2765 1415 2365 1080 1950 885 1580 700 2785 1475 2345 1135 1805 865 1515 690
2695 1385 2345 1050 1985 870 1620 695 2715 1435 2275 1080 1825 845 1560 685
2605 1335 2315 1030 1990 850 1645 690 2620 1380 2260 1035 1840 825 1600 680
2530 1300 2265 990 1990 825 1665 675 2550 1350 2230 1015 1845 815 1620 670
2420 1260 2210 955 1970 800 1675 665 2450 1305 2175 990 1850 790 1615 655
2330 1220 2145 925 1930 775 1665 650 2365 1270 2130 940 1830 775 1615 640
2250 1190 2050 885 1875 745 1645 630 2240 1205 2070 915 1815 760 1595 620
2135 1140 2000 865 1810 715 1620 615 2185 1190 1965 865 1775 745 1555 605
2030 1090 1885 830 1720 685 1560 590 2015 1150 1820 820 1690 715 1440 580
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
G61MP−60C−091 PERFORMANCE (Less Filter)
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional RAB Single Side Return Air − Air volumes in bold require field
Return Air Base, Return Air from Both Sides or Return fabricated transition to accommodate 20 x 25 x 1 in. air
External
Static
Air from Bottom and One Side.
filter in order to maintain proper air velocity.
Pressure
in. w.g.
Medium−
High
Medium−
Low
Medium−
High
Medium−
Low
High
Low
High
Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
2320 1230 2240 960 1970 810 1505 690 2350 1275 2195 960 1920 830 1535 680
2250 1195 2155 910 1950 805 1610 665 2270 1240 2125 930 1910 800 1580 665
2185 1165 2080 890 1915 775 1630 660 2200 1190 2060 905 1875 775 1570 655
2060 1120 1965 835 1795 710 1590 620 2070 1135 1945 830 1830 725 1545 625
1995 1095 1890 805 1720 690 1535 600 1935 1095 1875 815 1750 705 1495 605
1920 1060 1860 790 1705 665 1540 580 1910 1070 1820 780 1715 670 1510 585
1800 1025 1750 755 1605 640 1485 560 1825 1050 1720 760 1635 645 1450 555
1710 1000 1625 735 1500 605 1380 535 1705 1025 1605 725 1485 615 1360 535
1600 975 1545 700 1455 585 1335 515 1605 995 1515 700 1440 585 1320 510
1475 940 1405 670 1305 555 1105 450 1460 950 1370 665 1285 555 1175 480
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
Page 49
Download from Www.Somanuals.com. All Manuals Search And Download.
Blower Performance Data
G61MP−60C−110 PERFORMANCE (Less Filter)
Air Volume / Watts at Different Blower Speeds
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional RAB Single Side Return Air − Air volumes in bold require field
Return Air Base, Return Air from Both Sides or Return fabricated transition to accommodate 20 x 25 x 1 in. air
External
Static
Air from Bottom and One Side.
filter in order to maintain proper air velocity.
Pressure
in. w.g.
Medium−
High
Medium−
Low
Medium−
High
Medium−
Low
High
Low
High
Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
2720 1385 2410 1090 2055 935 1620 710 2625 1350 2310 1080 1885 885 1515 700
2665 1355 2385 1075 2025 885 1730 735 2570 1330 2325 1060 1910 865 1575 700
2585 1315 2350 1015 2030 865 1680 690 2410 1305 2285 1035 1930 845 1620 690
2505 1275 2290 990 2025 840 1695 675 2425 1265 2230 990 1925 825 1635 675
2435 1250 2235 940 2030 830 1695 660 2335 1220 2175 950 1910 810 1640 660
2350 1205 2170 930 1975 790 1735 665 2270 1195 2120 935 1895 785 1640 640
2255 1185 2100 895 1915 765 1720 650 2170 1155 2045 885 1860 765 1630 630
2160 1150 2005 840 1865 730 1680 635 2110 1130 1950 855 1795 730 1590 610
2020 1090 1905 825 1810 710 1625 610 2035 1090 1885 820 1745 705 1540 580
1910 1050 1820 795 1705 675 1540 590 1900 1055 1760 780 1665 680 1470 565
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
G61MP−60C−111 PERFORMANCE (Less Filter)
Air Volume / Watts at Different Blower Speeds
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional RAB Single Side Return Air − Air volumes in bold require field
Return Air Base, Return Air from Both Sides or Return fabricated transition to accommodate 20 x 25 x 1 in. air
External
Static
Air from Bottom and One Side.
filter in order to maintain proper air velocity.
Pressure
in. w.g.
Medium−
High
Medium−
Low
Medium−
High
Medium−
Low
High
Low
High
Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
2475 1305 2275 1010 1800 870 1425 680 2460 1355 2210 1045 1850 860 1435 670
2395 1260 2215 980 1850 850 1495 675 2395 1320 2170 1010 1850 830 1490 660
2340 1220 2165 945 1860 830 1535 665 2280 1270 2115 965 1875 810 1525 650
2255 1205 2085 915 1855 805 1545 655 2225 1250 2075 940 1835 785 1530 640
2165 1160 2000 880 1820 780 1540 645 2150 1210 2005 905 1800 760 1535 626
2055 1140 1920 845 1780 755 1535 625 2050 1155 1935 885 1760 740 1555 620
1995 1120 1845 825 1720 725 1485 605 1975 1140 1835 845 1660 705 1480 595
1880 1075 1760 800 1680 710 1470 595 1870 1110 1745 810 1620 685 1440 575
1795 1060 1640 755 1595 680 1415 570 1760 1065 1645 770 1510 655 1370 550
1680 1020 1530 725 1505 645 1345 550 1635 1025 1545 740 1415 620 1295 530
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
Page 50
Download from Www.Somanuals.com. All Manuals Search And Download.
G61MP−60D−135 PERFORMANCE (Less Filter)
Air Volume / Watts at Different Blower Speeds
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional RAB Single Side Return Air − Air volumes in bold require field
Return Air Base, Return Air from Both Sides or Return fabricated transition to accommodate 20 x 25 x 1 in. air
External
Static
Air from Bottom and One Side.
filter in order to maintain proper air velocity.
Pressure
in. w.g.
Medium−
High
Medium−
Low
Medium−
High
Medium−
Low
High
Low
High
Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
2730 1465 2425 1125 2055 915 1560 680 2665 1440 2325 1100 1865 890 1410 690
2670 1440 2400 1100 2065 890 1590 675 2615 1405 2310 1065 1915 865 1465 685
2600 1400 2365 1070 2045 865 1620 665 2530 1370 2280 1055 1925 850 1570 675
2525 1360 2315 1045 2035 845 1615 655 2470 1330 2235 1015 1920 825 1590 670
2445 1325 2260 1015 2020 820 1615 645 2380 1290 2175 985 1910 805 1590 655
2360 1280 2195 985 1960 790 1610 635 2310 1265 2120 965 1890 790 1595 645
2290 1255 2130 965 1900 755 1600 615 2200 1230 2055 935 1835 765 1580 630
2205 1220 2035 910 1825 730 1570 600 2120 1190 1970 900 1790 740 1545 605
2110 1195 1945 880 1765 710 1540 580 2025 1160 1890 875 1720 710 1515 590
1970 1120 1835 830 1680 690 1540 545 1930 1110 1800 835 1655 685 1440 570
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
NOTES − All air data is measured external to unit without filter (not furnished − field provided).
Page 51
Download from Www.Somanuals.com. All Manuals Search And Download.
Applications Using A Single−Stage Thermostat
Heating Sequence of Operation
B − Heating Sequence −− Control Board Thermostat
Selection DIP switch in ꢀSingle−Stage" Position
NOTE − The thermostat selection DIP switch on the control
board is factory−set in the ꢁTWO−STAGE" position.
Applications Using a Two−Stage Thermostat
A − Heating Sequence −− Control Board Thermostat
Selection DIP switch in ꢀTwo−Stage" Position (Factory
Setting)
NOTE − In these applications, two−stage heat will be initi-
ated by the integrated control if heating demand has not
been satisfied after the field adjustable period (10 or 15
minutes).
1 − On a call for heat, thermostat first−stage contacts close
sending a signal to the integrated control. The inte-
grated control runs a self-diagnostic program and
checks high temperature limit switches for normally
closed contacts and pressure switches for normally
open contacts.The combustion air inducer is ener-
gized at low speed and the humidifier terminal is ener-
gized.
1 − On a call for heat, thermostat first−stage contacts close
sending a signal to the integrated control. The inte-
grated control runs a self-diagnostic program and
checks high temperature limit switches for normally
closed contacts and pressure switches for normally
open contacts.The combustion air inducer is ener-
gized at low speed and the humidifier terminal is ener-
gized.
2 − Once the control receives a signal that the low−fire
pressure switch has closed, the combustion air induc-
er begins a 15−second pre−purge in low speed.
3 − After the pre−purge is complete, a 20−second initial ig-
nitor warm−up period begins. The combustion air in-
ducer continues to operate at low speed.
2 − Once the control receives a signal that the low−fire
pressure switch has closed, the combustion air induc-
er begins a 15−second pre−purge in low speed.
3 − After the pre−purge is complete, a 20−second initial ig-
nitor warm−up period begins. The combustion air in-
ducer continues to operate at low speed.
4 − After the 20−second warm−up period has ended, the gas
valve is energized on low fire (first stage) and ignition oc-
curs. At the same time, the control module sends a sig-
nal to begin an indoor blower 45−second ON−delay.
When the delay ends, the indoor blower motor is ener-
gized on the low fire heating speed. The furnace will
continue this operation as long as the thermostat has
a first−stage heating demand.
4 − After the 20−second warm−up period has ended, the gas
valve is energized on low fire (first stage) and ignition oc-
curs. At the same time, the control module sends a sig-
nal to begin an indoor blower 45−second ON−delay.
When the delay ends, the indoor blower motor is ener-
gized on the low−fire heating speed. The integrated
control also initiates a second−stage on delay (factory−
set at 10 minutes; adjustable to 15 minutes).
5 − If second−stage heat is required, the thermostat sec-
ond−stage heat contacts close and send a signal to the
integrated control. The integrated control initiates a
30−second second−stage recognition delay.
5 − If the heating demand continues beyond the second−
stage on delay, the integrated control energizes the
combustion air inducer at high speed. The control also
checks the high−fire (second stage) pressure switch to
make sure it is closed. Once the control receives a sig-
nal the high−fire pressure switch is closed, the high−fire
(second stage) gas valve is energized and the indoor
blower motor is energized for operation at the high−fire
heating speed.
6 − At the end of the recognition delay, the integrated con-
trol energizes the combustion air inducer at high
speed. The control also checks the high−fire (second
stage) pressure switch to make sure it is closed. Once
the the control receives a signal that the high−fire pres-
sure switch is close, the high−fire (second stage) gas
valve is energized and the indoor blower motor is en-
ergized for operation at the high−fire heating speed.
7 − When the demand for high−fire (second stage) heat is
satisfied, the combustion air inducer is switched to the
low−fire heating speed and the high−fire (second
stage) gas valve is de−energized. The low−fire (first
stage) gas valve continues operation. The indoor
blower motor is switched to the low−fire heating speed.
8 − When the thermostat demand for low−fire (first stage)
heat is satisfied, the gas valve is de−energized and the
field−selected indoor blower off delay begins. The
combustion air inducer begins a 5−second post−purge
period.
6 − When the thermostat heating demand is satisfied, the-
combustion air inducer begins a 5−second post−purge.
The field−selected indoor blower off delay begins.
7 − When the combustion air post−purge period is com-
plete, the inducer and humidifier terminal are de−ener-
gized. The indoor blower is de−energized at the end of
the off delay.
9 − When the combustion air post−purge period is com-
plete, the inducer and humidifier terminal are de−ener-
gized. The indoor blower is de−energized at the end of
the off delay.
Page 52
Download from Www.Somanuals.com. All Manuals Search And Download.
3 − Remove the drain plug from the condensate trap and
empty water. Inspect the trap then reinstall the drain
plug.
Service
Cleaning Heat Exchanger
WARNING
ELECTRICAL SHOCK, FIRE,
OR EXPLOSION HAZARD.
If cleaning the heat exchanger becomes necessary, follow
the below procedures and refer to figure 1 when disassem-
bling unit. Use papers or protective covering in front of fur-
nace while removing heat exchanger assembly.
Failure to follow safety warnings exactly could result
in dangerous operation, serious injury, death or
property damage.
1 − Turn off electrical and gas supplies to the furnace.
2 − Remove the upper and lower furnace access panels.
Improper servicing could result in dangerous opera-
tion, serious injury, death, or property damage.
Before servicing, disconnect all electrical power to
furnace.
When servicing controls, label all wires prior to dis-
connecting. Take care to reconnect wires correctly.
Verify proper operation after servicing.
3 − Mark all gas valve wires and disconnect them from
valve.
4 − Remove gas supply line connected to gas valve. Re-
move gas valve/manifold assembly.
5 − Remove sensor wire from sensor. Disconnect 2-pin
plug from the ignitor.
6 − Disconnect wires from flame roll−out switches.
At the beginning of each heating season, system should be
checked as follows by a qualified service technician:
7 − Remove burner box cover and remove four burner box
screws at the vestibule panel and remove burner box.
Set burner box assembly aside.
Blower
NOTE − G61MP−135 units are secured to the vestibule
panel by two additional screws. These screws must be
removed for servicing; however it is not necessary to
replace the screws.
Check the blower wheel for debris and clean if necessary.
The blower motors are prelubricated for extended bearing
life. No further lubrication is needed.
NOTE − If necessary, clean burners at this time. Follow
procedures outlined in Burner Cleaning section.
8 − Loosen three clamps and remove flexible exhaust tee.
WARNING
9 − Remove 3/8 inch rubber cap from condensate drain
plug and drain. Replace cap after draining.
The blower access panel must be securely in place
when the blower and burners are operating. Gas
fumes, which could contain carbon monoxide, can
be drawn into living space resulting in personal inju-
ry or death.
10 − Disconnect condensate drain line from the conden-
sate trap. Remove condensate trap (it may be neces-
sary to cut drain pipe). Remove screws that secure
condensate collars to either side of the furnace and re-
move collars. Remove drain tubes from cold end
header collector box.
Filters
All G61MP filters are installed external to the unit. Filters
should be inspected monthly. Clean or replace the filters
when necessary to ensure proper furnace operation.
11 − Disconnect condensate drain tubing from flue collar.
Remove screws that secure both flue collars into
place. Remove flue collars. It may be necessary to cut
the exiting exhaust pipe for removal of the fittings.
Exhaust and air intake pipes
12 − Mark and disconnect all combustion air pressure tub-
ing from cold end header collector box.
Check the exhaust and air intake pipes and all connections
for tightness and to make sure there is no blockage.
13 − Mark and remove wires from pressure switches. Re-
move pressure switches. Keep tubing attached to
pressure switches.
NOTE − After any heavy snow, ice or frozen fog event the
furnace vent pipes may become restricted. Always check
the vent system and remove any snow or ice that may be
obstructing the plastic intake or exhaust pipes.
14 − Disconnect the 3-pin plug from the combustion air in-
ducer. Disconnect the two wires to the backup secon-
dary limit, if applicable. Remove four screws which se-
cure combustion air inducer to collector box. Remove
combustion air inducer assembly. Remove ground
wire from vest panel.
Electrical
1 − Check all wiring for loose connections.
2 − Check for the correct voltage at the furnace (furnace
operating).
15 − Remove electrical junction box from the side of the fur-
nace.
3 − Check amp−draw on the blower motor.
Motor Nameplate__________Actual__________
16 − Mark and disconnect any remaining wiring to heating
compartment components. Disengage strain relief
bushing and pull wiring and bushing through the hole in
the blower deck.
Winterizing and Condensate Trap Care
1 − Turn off power to the unit.
2 − Have a shallow pan ready to empty condensate water.
Page 53
Download from Www.Somanuals.com. All Manuals Search And Download.
17 − Remove the primary limit from the vestibule panel.
38 − Secure burner box assembly to vestibule panel using
four existing screws. Make sure burners line up in
center of burner ports.
18 − Remove two screws from the front cabinet flange at
the blower deck. Spread cabinet sides slightly to allow
clearance for removal of heat exchanger.
39 − Reinstall gas valve manifold assembly. Reconnect
gas supply line to gas valve.
19 − Remove screws along vestibule sides and bottom
which secure vestibule panel and heat exchanger as-
sembly to cabinet. Remove two screws from blower
rail which secure bottom heat exchanger flange. Re-
move heat exchanger from furnace cabinet.
40 − Reinstall burner box cover.
41 − Reconnect wires to gas valve.
42 − Replace the blower compartment access panel.
43 − Refer to instruction on verifying gas and electrical con-
nections when re−establishing supplies.
20 − Back wash heat exchanger with soapy water solution
or steam. If steam is used it must be below 275°F
(135°C) .
44 − Follow lighting instructions to light and operate fur-
nace for 5 minutes to ensure that heat exchanger is
clean and dry and that furnace is operating properly.
21 − Thoroughly rinse and drain the heat exchanger. Soap
solutions can be corrosive. Take care to rinse entire
assembly.
45 − Replace heating compartment access panel.
Cleaning the Burner Assembly
22 − Reinstall heat exchanger into cabinet making sure that
the clamshells of the heat exchanger assembly are
resting on the support located at the rear of the cabi-
net. Remove the indoor blower to view this area
through the blower opening.
1 − Turn off electrical and gas power supplies to furnace.
Remove upper and lower furnace access panels.
2 − Mark all gas valve wires and disconnect them from the
valve.
23 − Re-secure the supporting screws along the vestibule
sides and bottom to the cabinet.
3 − Disconnect the gas supply line from the gas valve. Re-
move gas valve/manifold assembly.
24 − Reinstall cabinet screws on front flange at blower
deck.
4 − Mark and disconnect sensor wire from the sensor. Dis-
connect 2-pin plug from the ignitor at the burner box.
25 − Reinstall the primary limit on the vestibule panel.
5 − Remove burner box cover and remove four screws
which secure burner box assembly to vest panel. Re-
move burner box from the unit.
26 − Route heating component wiring through hole in blow-
er deck and reinsert strain relief bushing.
NOTE − G61MP−135 units are secured to the vestibule
panel by two additional screws. These screws must be
removed for servicing; however it is not necessary to
replace the screws.
27 − Reinstall electrical junction box.
28 − Reinstall the combustion air inducer. Reconnect the
3−pin plug to the wire harness. Reconnect the two
wires to the backup secondary limit, if applicable.
6 − Use the soft brush attachment on a vacuum cleaner to
gently clean the face of the burners. Visually inspect
the inside of the burners and crossovers for any block-
age caused by foreign matter. Remove any blockage.
29 − Reinstall pressure switches and reconnect pressure
switch wiring.
30 − Carefully connect combustion air pressure switch
hosing from pressure switches to proper stubs on
cold end header collector box.
7 − Reconnect the sensor wire and reconnect the 2−pin
plug to the ignitor wiring harness.
31 − Reinstall condensate collars on each side of the fur-
nace. Reconnect drain tubing to collector box.
8 − Reinstall the burner box assembly using the existing
four screws. Make sure that the burners line up in the
center of the burner ports.
32 − Reinstall condensate trap on same side as exhaust
pipe. Reconnect condensate drain line to the conden-
sate trap.
9 − Reinstall the gas valve manifold assembly. Reconnect
the gas supply line to the gas valve. Reinstall the burn-
er box cover.
33 − Use securing screws to reinstall flue collars to either
side of the furnace. Reconnect exhaust piping and ex-
haust drain tubing.
10 − Reconnect the gas valve wires to the gas valve.
11 − Replace the blower compartment access panel.
34 − Replace flexible exhaust tee on combustion air induc-
er and flue collars. Secure using three existing hose
clamps.
12 − Refer to instruction on verifying gas and electrical con-
nections when re−establishing supplies.
35 − Reinstall burner box assembly in vestibule area.
36 − Reconnect flame roll−out switch wires.
13 − Follow lighting instructions to light and operate fur-
nace for 5 minutes to ensure that heat exchanger is
clean and dry and that furnace is operating properly.
37 − Reconnect sensor wire and reconnect 2−pin plug from
ignitor.
14 − Replace heating compartment access panel.
Page 54
Download from Www.Somanuals.com. All Manuals Search And Download.
Return air duct − Must be properly attached and provide
Planned Service
an air seal to the unit.
A service technician should check the following items dur-
ing an annual inspection. Power to the unit must be shut off
for safety.
Operating performance − Unit must be observed during
operation to monitor proper performance of the unit and the
vent system.
Fresh air grilles and louvers (on the unit and in the room
where the furnace is installed) − Must be open and unob-
structed to provide combustion air.
Combustion gases − Flue products must be analyzed and
compared to the unit specifications.
Problems detected during the inspection may make it nec-
essary to temporarily shut down the furnace until the items
can be repaired or replaced.
Burners − Must be inspected for rust, dirt, or signs of water.
Vent pipe − Must be inspected for signs of water, damaged,
cracked or sagging pipe, or disconnected joints.
Instruct the homeowners to pay attention to their
furnace. Situations can arise between annual furnace in-
spections that may result in unsafe operation. For instance,
items innocently stored next to the furnace may obstruct
the combustion air supply. This could cause incomplete
combustion and the production of carbon monoxide gas.
Unit appearance − Must be inspected for rust, dirt, signs
of water, burnt or damaged wires, or components.
Blower access door − Must be properly in place and pro-
vide a seal between the return air and the room where the
furnace is installed.
Page 55
Download from Www.Somanuals.com. All Manuals Search And Download.
Ignition Control Board Diagnostic Codes
FLASH CODE
(X + Y)
STATUS / ERROR DESCRIPTION
FLASH CODE DESCRIPTIONS
Pulse
A 1/4 second flash followed by four seconds of off time.
Heartbeat
Constant 1/2 second bright and 1/2 second dim cycles.
LED flashes X times at 2Hz, remains off for two seconds, flashes Y times at 2Hz, remains off for four
seconds, then repeats.
X + Y
Pulse
Power on − Standby.
Heartbeat
Normal operation − signaled when heating demand initiated at thermostat.
FLAME CODES
1 + 2
1 + 3
Low flame current −− run mode.
Flame sensed out of sequence −− flame still present.
PRESSURE SWITCH CODES
2 + 3
2 + 4
2 + 5
2 + 6
2 + 7
Low pressure switch failed open.
Low pressure switch failed closed.
High pressure switch failed open.
High pressure switch failed closed.
Low pressure switch opened during ignition trial or heating demand.
LIMIT CODE
3 + 1
Limit switch open.
WATCHGUARD CODES
4 + 1
4 + 2
4 + 3
4 + 5
4 + 6
4 + 7
4 + 8
Watchguard −− Exceeded maximum number of retries.
Watchguard −− Exceeded maximum number of retries or last retry was due to pressure switch opening.
Watchguard −− Exceeded maximum number of retries or last retry was due to flame failure.
Watchguard −− Limit remained open longer than three minutes.
Watchguard −− Flame sensed out of sequence; flame signal gone.
Ignitor circuit fault −− Failed ignitor or triggering circuitry.
Low line voltage.
HARD LOCKOUT CODES
5 + 1
5 + 2
5 + 3
5 + 4
5 + 6
Hard lockout −− Rollout circuit open or previously opened.
Control failed self check, internal error (control will restart if error recovers).
No Earth ground (control will restart if error recovers).
Reversed line voltage polarity (control will restart if the error recovers).
Low secondary (24VAC) voltage.
Error Code Storage
5 − After final error code is indicated, STATUS LED will
flash to indicate normal operation.
The ignition control stores the last ten error codes in
memory. The codes are retained in case of power loss.
Clearing Error Codes
Error Code Review
1 − Short R (2) to (1). Within 1/2 second, the STATUS LED
will stay lit continuously to indicate that the short was
sensed.
1 − Short R (2) to (1). Within 1/2 second, the STATUS LED
will stay lit continuously to indicate that the short was
sensed.
2 − Continue to hold the short between R (2) to (1). After 5
seconds, STATUS LED will go from being continuously
lit to off.
2 − Continue to hold the short between R (2) to (1). After 5
seconds, STATUS LED will go from being continuously
lit to off. This indicates that error code review is pend-
ing.
3 − Continue to hold the short between R (2) to (1) beyond
ten seconds after STATUS LED has turned off. STA-
TUS LED will turn on, indicating that error codes have
been cleared.
3 − Remove R (2) to (1) short within ten seconds of STA-
TUS LED turning off. This activates error code review.
4 − Last ten error codes will be flashed on the STATUS
LED.
4 − Remove R (2) to (1) short. STATUS LED will flash to in-
dicate normal operation.
Page 56
Download from Www.Somanuals.com. All Manuals Search And Download.
Troubleshooting: Heating Sequence of Operation
HEATING SEQUENCE OF OPERATION
NORMAL AND ABNORMAL HEATING MODE
POWER ON
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF. (RESET CONTROL BY
TURNING MAIN POWER OFF.)
NO
NO
CONTROL SELF−CHECK OKAY?
POLARITY REVERSED.
STATUS ERROR CODE 5 + 4.
POLARITY OKAY?
YES
NO
IS THERE A
PROPER GROUND?
SIGNAL HOLDS UNTIL UNIT IS PROPERLY GROUNDED.
STATUS ERROR CODE 5 + 3.
YES
A
NORMAL OPERATION:
STATUS LED −− PULSE
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER ON. HAS PRIMARY OR
SECONDARY LIMIT RESET WITHIN 3 MINUTES?
STATUS ERROR CODE 3 + 1.
YES
B
THERMOSTAT CALLS FOR HEAT:
STATUS LED −− HEARTBEAT
NO
NO
NO
60−MINUTE LIMIT WATCHGUARD MODE.
GAS VALVE OFF, COMBUSTION AIR INDUCER
OFF, INDOOR BLOWER OFF WITH DELAY.
STATUS ERROR CODE 4 + 5.
YES
PRIMARY AND SECONDARY LIMIT
SWITCHES CLOSED?
YES
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER ON.
STATUS ERROR CODE 5 + 1.
SEQUENCE HOLDS UNTIL ROLLOUT SWITCH IS
RESET AND MAIN POWER IS INTERRUPTED OR
T’STAT IS CYCLED OFF/ON FOR 3 SEC. MINIMUM.
NO
ROLLOUT SWITCH CLOSED?
NO
YES
YES
FIRST (LOW) STAGE PRESSURE SWITCH
CONTACTS OPEN?
NO
YES
GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF. CONTROL REMAINS UNTIL
PRESSURE SWITCH IS DETECTED OPEN.
STATUS ERROR CODE 2 + 4
SECOND (HIGH) STAGE PRESSURE SWITCH
CONTACTS OPEN?
NO
YES
GAS VALVE OFF.
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF.
TWO−STAGE OR SINGLE−STAGE THERMOSTAT
CALL FOR HEAT
CONTROL WILL NOT ATTEMPT SECOND−STAGE
OPERATION DURING THIS HEAT DEMAND.
FIRST−STAGE OPERATION WILL BE ATTEMPTED.
STATUS ERROR CODE 2 + 6.
COMBUSTION AIR INDUCER ON LOW SPEED.
STATUS LED −− HEARTBEAT
CONTINUED ON NEXT PAGE
Page 57
Download from Www.Somanuals.com. All Manuals Search And Download.
Troubleshooting: Heating Sequence of Operation (Continued)
HEATING SEQUENCE OF OPERATION
CONTINUED
THERMOSTAT CALLS FOR HEAT
STATUS LED − HEARTBEAT.
(Refer to box A on previous page)
NO
FIRST−STAGE (LOW FIRE) PRESSURE
SWITCH CLOSED WITHIN 2.5 MINUTES?
GAS VALVE OFF. COMBUSTION AIR INDUCER
OFF. INDOOR BLOWER OFF. UNIT WILL RETRY
AFTER 5−MINUTE WAIT PERIOD.
YES
STATUS ERROR CODE 2 + 3.
15−SECOND COMBUSTION AIR INDUCER
PRE−PURGE INITIATED BY CLOSED FIRST−STAGE
PRESSURE SWITCH (or 15 SECOND
INTER−PURGE PERIOD.)
STATUS LED −− HEARTBEAT.
IGNITOR WARM−UP (20 SECONDS)
STATUS LED −− HEARTBEAT.
YES
COMBUSTION AIR INDUCER OFF, IGNITOR OFF.
SIGNAL HOLDS UNTIL IGNITOR IS REPLACED OR
RECONNECTED.
NO
IS IGNITOR INTACT AND CONNECTED?
STATUS ERROR CODE 4 + 7.
YES
AT END OF IGNITOR 20 SECOND WARM UP
PERIOD, 4−SECOND TRIAL FOR IGNITION.
GAS VALVE OPENS, IGNITOR ENERGIZED DURING
4−SECOND TRIAL UNTIL FLAME SENSED.
YES
IS VOLTAGE ABOVE 90 VOLTS?
NO
YES
COMBUSTION AIR INDUCER OFF, IGNITER OFF.
SIGNAL HOLDS UNTIL VOLTAGE RISES ABOVE 95
VOLTS. STATUS ERROR CODE 4 + 8.
4−SECOND FLAME STABILIZATION PERIOD.
NO
FLAME RECTIFICATION CURRENT CHECK
CAN FLAME BE PROVEN WITHIN 4
SECONDS AFTER GAS VALVE OPENS?
(u0.20 microamps)
GAS VALVE OFF. COMBUSTION AIR
INDUCER ON. INDOOR BLOWER OFF.
STATUS LED −− HEARTBEAT.
HAS CONTROL FAILED TO SENSE
FLAME FOR FIVE CONSECUTIVE TRIES
DURING A SINGLE HEAT DEMAND?
NO
YES
WATCHGUARD MODE. GAS VALVE OFF,
COMBUSTION AIR INDUCER OFF.
INDOOR BLOWER OFF.
YES
STATUS ERROR CODE 4 + 1.
IS 60−MINUTE RESET PERIOD COMPLETE?
YES
NO
FLAME PRESENT?
HAS CONTROL RESET IGNITION SEQUENCE
FOUR (4) TIMES?
WATCHGUARD MODE.
NO
YES
STATUS ERROR CODE 4 + 3.
CONTINUED ON NEXT PAGE
Page 58
Download from Www.Somanuals.com. All Manuals Search And Download.
Troubleshooting: Heating Sequence of Operation (Continued)
HEATING SEQUENCE OF OPERATION
CONTINUED
THERMOSTAT CALLS FOR HEAT.
STATUS LED −− HEARTBEAT.
SEE BOX A.
FLAME SIGNAL ABOVE
(u1.40 microamps)
NO
LOW FLAME SIGNAL
(Does not affect control operation)
STATUS ERROR CODE 1 + 2.
YES
YES
SINGLE−STAGE THERMOSTAT MODE
(DIP SWITCH SET AT ꢁSINGLE")
TWO STAGE THERMOSTAT MODE
(DIP SWITCH SET AT ꢁTWO")
YES
YES
START SECOND−STAGE RECOGNITION
ON DELAY (10 OR 15 MINUTES).
STATUS LED −− HEARTBEAT
45−SECOND INDOOR BLOWER ON DELAY BEGINS.
STATUS LED −− HEARTBEAT.
YES
NO
YES
NO
PRIMARY & SECONDARY LIMIT SWITCHES
CLOSED?
ROLLOUT SWITCHES CLOSED?
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER ON.
YES
STATUS ERROR CODE 5 + 1. SEQUENCE HOLDS
UNTIL ROLLOUT SWITCH IS RESET AND MAIN
POWER IS INTERRUPTED OR THERMOSTAT
IS CYCLED OFF/ON FOR 3 SECOND MINIMUM.
YES
FIRST−STAGE (LOW FIRE)
PRESSURE SWITCH CLOSED?
NO
YES
NO
GAS VALVE OFF, COMBUSTION AIR INDUCER OFF,
INDOOR BLOWER ON.
STATUS ERROR CODE 3 + 1.
FIRST−STAGE HEAT DEMAND SATISFIED?
YES
YES
YES
HAS PRIMARY OR SECONDARY LIMIT
SWITCH CLOSED WITHIN 3 MINUTES?
(Indoor blower on low speed during 3−minute period)
GAS VALVE OFF, COMBUSTION AIR INDUCER
OFF FOLLOWING POST PURGE.
INDOOR BLOWER OFF WITH DELAY
STATUS LED −− PULSE
NO
LIMIT SWITCH WATCHGUARD MODE.
GAS VALVE OFF, COMBUSTION AIR INDUCER OFF,
INDOOR BLOWER OFF WITH DELAY.
SECOND−STAGE HEAT DEMAND.
SECOND−STAGE HEAT DEMAND REQUIRED?
STATUS ERROR CODE 4 + 5
IS 60−MINUTE RESET PERIOD COMPLETE?
YES
SECOND STAGE PRESSURE SWITCH CLOSED?
ABNORMAL FLASH CODE.
NOTE − IF SECOND−STAGE PRESSURE SWITCH
WAS ORIGINALLY FOUND CLOSED,
ABNORMAL CODE WILL FLASH.
GAS VALVE OFF. COMBUSTION AIR INDUCER ON.
INDOOR BLOWER OFF AFTER DELAY.
STATUS ERROR CODE 2 + 3. CONTROL RESTARTS YES
IGNITION SEQUENCE IF PRESSURE SWITCH
CLOSES WITHIN 2−1/2 MINUTES.
YES
NO
SECOND−STAGE PRESSURE SWITCH CLOSED
AT BEGINNING OF HEAT DEMAND?
STATUS ERROR CODE 2 + 6.
NO
SECOND−STAGE 30−SECOND DELAY ON BEGINS.
STATUS LED −− HEARTBEAT.
YES
SECOND STAGE HEAT DEMAND
STATUS LED −− HEARTBEAT.
SECOND−STAGE COMBUSTION AIR INDUCER
ON. SECOND−STAGE GAS VALVE ON. HIGH
HEAT INDOOR BLOWER SPEED ON.
STATUS LED −− HEARTBEAT.
NO
RETURNS TO FIRST−STAGE HEAT MODE WHICH
CONTINUES UNTIL SECOND−STAGE PRESSURE
SWITCH CAN BE PROVEN or HEAT DEMAND IS
SATISFIED. FIVE (5) MINUTE WAIT PERIOD
INITIATED BEFORE RETRY. WERE 5 ATTEMPTS
MADE FOR SECOND−STAGE HEAT?
YES
SECOND−STAGE PRESSURE SWITCH CLOSED
IN LESS THAN TEN (10) SECONDS?
STATUS LED −− HEARTBEAT
NO
YES
CONTINUES FIRST−STAGE HEATING DEMAND.
WILL NOT REATTEMPT SECOND−STAGE
HEATING DEMAND.
YES
CONTINUED ON NEXT PAGE
STATUS ERROR CODE 2 + 5.
Page 59
Download from Www.Somanuals.com. All Manuals Search And Download.
Troubleshooting: Heating Sequence of Operation (Continued)
HEATING SEQUENCE OF OPERATION
CONTINUED
SEE BOX A
NORMAL OPERATION.
SEE BOX B
THERMOSTAT CALLS FOR HEAT.
RETURN TO FIRST−STAGE HEAT MODE.
FIRST−STAGE CONTINUES UNTIL SECOND−
STAGE PRESSURE SWITCH CAN BE PROVEN
or HEAT DEMAND IS SATISFIED. A FIVE (5)
MINUTE WAIT PERIOD IS INITIATED BEFORE
RETRY. WERE 5 ATTEMPTS MADE FOR
SECOND−STAGE HEAT?
SECOND−STAGE (HIGH FIRE) HEAT
PRESSURE SWITCH CLOSED?
YES
NO
YES
NO
HEAT DEMAND SATISFIED?
STATUS LED −− HEARTBEAT.
SEE BOX C
FIRST−STAGE HEAT DEMAND SATISFIED?
YES
YES
SINGLE−STAGE THERMOSTAT MODE
(DIP SWITCH SET AT ꢁSINGLE")
TWO STAGE THERMOSTAT MODE?
(DIP SWITCH SET AT ꢁTWO")
YES
YES
SECOND STAGE HEAT
DEMAND SASTISFIED?
STATUS LED −− HEARTBEAT.
FIRST AND SECOND STAGE HEAT
DEMAND SATISFIED SIMULTANEOUSLY.
STATUS LED −− HEARTBEAT.
GAS VALVE OFF, COMBUSTION AIR
INDUCER OFF AFTER 5−SECOND
LOW SPEED POST PURGE PERIOD,
INDOOR BLOWER OFF DELAY
INITIATED ON LOW HEAT SPEED.
STATUS LED −− HEARTBEAT.
YES
NO
YES
GAS VALVE, COMBUSTION AIR INDUCER
AND INDOOR BLOWER RETURN TO FIRST−
STAGE OPERATION.
STATUS LED −− HEARTBEAT.
FIRST STAGE HEAT DEMAND SATISFIED?
YES
GAS VALVE OFF. COMBUSTION AIR INDUCER
OFF AFTER 5−SECOND LOW SPEED POST−
PURGE PERIOD. INDOOR BLOWER OFF.
DELAY INITIATED ON LOW HEAT SPEED.
STATUS LED −− PULSE.
DEMAND FOR HEAT SATISFIED.
POWER ON STAND BY.
STATUS LED −− PULSE.
Page 60
Download from Www.Somanuals.com. All Manuals Search And Download.
Troubleshooting: Cooling Sequence of Operation
COOLING SEQUENCE OF OPERATION
POWER ON
SIGNAL POLARITY REVERSED.
CONTROL WILL CONTINUE TO CALL FOR COOLING
IN THIS CONDITION.
YES
IS POLARITY REVERSED?
STATUS ERROR CODE 5 + 4.
NO
SIGNAL IMPROPER GROUND AT LED.
CONTROL WILL CONTINUE TO CALL FOR COOLING
IN THIS CONDITION.
NO
IS THERE
PROPER GROUND?
STATUS ERROR CODE 5 + 3.
YES
THERMOSTAT CALLS FOR FIRST−STAGE COOL.
COMPRESSOR AND CONDENSER FAN
ENERGIZED.
INDOOR BLOWER ENERGIZED ON FIRST STAGE
COOL SPEED AFTER 2 SECOND DELAY.
YES
COMPRESSOR AND CONDENSER FAN DE−ENERGIZED.
INDOOR BLOWER DE−ENEGIZED.
FIRST−STAGE DEMAND FOR COOL SATISFIED?
NO
THERMOSTAT CALLS FOR SECOND−STAGE COOL.
INDOOR BLOWER RAMPS UP TO SECOND−STAGE COOL SPEED.
SECOND−STAGE DEMAND FOR COOL SATISFIED?
YES
UNIT RETURNS TO FIRST STAGE COOL
Page 61
Download from Www.Somanuals.com. All Manuals Search And Download.
Troubleshooting: Continuous Fan Sequence of Operation
CONTINUOUS LOW SPEED FAN SEQUENCE OF OPERATION
MANUAL FAN SELECTION MADE AT THERMOSTAT.
AFTER 2 SECOND DELAY, INDOOR BLOWER IS
ENERGIZED ON CONTINUOUS FAN SPEED.
YES
YES
THERMOSTAT CALLS FOR FIRST STAGE COOL.
YES
THERMOSTAT CALLS FOR FIRST−STAGE HEAT.
YES
INDOOR BLOWER RAMPS TO FIRST STAGE
COOLING SPEED AFTER A 2−SECOND DELAY.
AFTER 45−SECOND DELAY, INDOOR BLOWER
SWITCHES TO LOW HEAT SPEED.
FIRST−STAGE COOL DEMAND SATISFIED?
FIRST−STAGE HEAT DEMAND SATISFIED.
NO
YES
YES
NO
SECOND STAGE COOL DEMAND
THERMOSTAT CALLS FOR SECOND−STAGE HEAT.
YES
INDOOR BLOWER RAMPS TO SECOND
STAGE COOL SPEED
INDOOR BLOWER SWITCHES TO HIGH HEAT SPEED
AFTER 30−SECOND RECOGNITION PERIOD.
YES
SECOND STAGE COOL DEMAND SATISFIED?
YES
SECOND−STAGE HEAT DEMAND SATISFIED.
YES
INDOOR BLOWER RAMPS DOWN TO FIRST STAGE
COOL SPEED.
INDOOR BLOWER RAMPS DOWN TO LOW
HEAT SPEED.
Repair Parts List
The following repair parts are available through Lennox dealers. When ordering parts, include the complete furnace model
number listed on the CSA nameplate −− Example: G61MP−36B−045−1. All service must be performed by a licensed pro-
fessional installer (or equivalent), service agency, or gas supplier.
Cabinet Parts
Upper access panel
Heating Parts
Flame Sensor
Blower access panel
Top Cap
Heat exchanger assembly
Gas manifold
Control Panel Parts
Transformer
Combustion air inducer
Gas valve
Two−stage integrated control board
Door interlock switch
Circuit Breaker
Main burner cluster
Main burner orifices
Pressure switches
Ignitor
Blower Parts
Blower wheel
Motor
Primary limit control
Secondary limit control
Flame rollout switches
Combustion air inducer auxiliary limit
Motor mounting frame
Motor capacitor
Blower housing cutoff plate
Page 62
Download from Www.Somanuals.com. All Manuals Search And Download.
Vent Pipe Sizing Worksheet
Step 1
Step 2
Proposed vent pipe size : ______
Equivalent Feet
Termination kit catalog number : _____________
Step 3
Step 4
Total number of 90° elbows required (indoors and outdoors)
______ X 5 = ______ equivalent feet of pipe
Total number of 45° elbows required (indoors and outdoors)
______ X 2.5 = ______ equivalent feet of pipe
Step 5
Step 6
Linear feet of straight pipe required : ______
TOTAL
Add equivalent feet of vent pipe listed in
steps 2 through 5.
If the total is equal to, or less than, the allowable maximum given in table 6, the proposed pipe size is acceptable. If the
total exceeds the maximum allowed vent pipe length, repeat the process above using the next larger diameter pipe until
an acceptable total is achieved.
NOTE − In Direct Vent systems, total the equivalent length of either the exhaust OR intake piping run, depending upon which
will be LONGER. Intake and exhaust pipe diameter must be the same size and must be terminated in the same pressure
zone. Intake and exhaust pipe should be roughly the same length.
G61MP Start−Up & Performance Check List
Job Name
Job No.
City
Date
State
State
Job Location
Installer
City
Technician
Unit Model No.
Serial No.
Heating Section
Electrical Connections Tight?
Line Voltage
Blower Motor H.P.
Gas Piping Connections
Tight & Leak−Tested?
Blower Motor Amps
Fuel Type: Natural Gas?
LP/Propane Gas?
Furnace Btu Input (High fire)
Low Fire Manifold Pressure
High Fire Manifold Pressure
Flue Connections Tight?
Line Pressure
w.c. − LP/Propane
w.c. − LP/Propane
Proper Draft?
w.c. − Nat.:
w.c. − Nat.:
Combustion Gas Tested (high fire and low fire)?
CO
CO
2
Blower ON delay confirmed?
(45 Seconds Fixed On)
External Static Pressure?
(0.5 maximum)
Temperature Rise
Blower OFF Delay Setting (60, 90, 120 or 180)?
Filter Clean & Secure?
Thermostat
Heat Anticipator Setting?
Thermostat Level?
Page 63
Download from Www.Somanuals.com. All Manuals Search And Download.
Requirements for Commonwealth of Massachusetts
Modifications to NFPA−54, Chapter 10
4 − INSPECTION. The state or local gas inspector of the
side wall, horizontally vented, gas−fueled equipment
shall not approve the installation unless, upon inspec-
tion, the inspector observes carbon monoxide detec-
tors and signage installed in accordance with the pro-
visions of 248 CMR 5.08(2)(a) 1 through 4.
Revise NFPA−54 section 10.8.3 to add the following re-
quirements:
For all side wall, horizontally vented, gas−fueled equipment
installed in every dwelling, building or structure used in
whole or in part for residential purposes, including those
owned or operated by the Commonwealth and where the
side wall exhaust vent termination is less than seven (7)
feet above the finished grade in the area of the venting, in-
cluding but not limited to decks and porches, the following
requirements shall be satisfied:
EXEMPTIONS: The following equipment is exempt
from 24 CMR 5.08(2)(a) 1 through 4:
1 − The equipment listed in Chapter 10 entitled ꢁEquip-
ment Not Required to Be Vented" in the most current
edition of NFPA 54 as adopted by the Board; and
2 − Product Approved side wall, horizontally vented, gas−
fueled equipment installed in a room or structure sepa-
rate from the dwelling, building or structure used in
whole or in part for residential purposes.
1 − INSTALLATION OF CARBON MONOXIDE DETEC-
TORS. At the time of installation of the side wall, hori-
zontally vented, gas−fueled equipment, the installing
plumber or gasfitter shall observe that a hard−wired
carbon monoxide detector with an alarm and battery
backup is installed on the floor level where the gas
equipment is to be installed. In addition, the installing
plumber or gasfitter shall observe that a battery−oper-
ated or hard−wired carbon monoxide detector with an
alarm is installed on each additional level of the dwell-
ing, building or structure served by the side wall, hori-
zontally vented, gas−fueled equipment. It shall be the
responsibility of the property owner to secure the ser-
vices of qualified licensed professionals for the instal-
lation of hard−wired carbon monoxide detectors.
MANUFACTURER REQUIREMENTS −
GAS EQUIPMENT VENTING SYSTEM PROVIDED.
When the manufacturer of Product Approved side wall,
horizontally vented, gas−fueled equipment provides a vent-
ing system design or venting system components with the
equipment, the instructions provided by the manufacturer
for installation of the equipment and the venting system
shall include:
1 − Detailed instructions for the installation of the venting
system design or the venting system components:
and
a − In the event that the side wall, horizontally vented,
gas−fueled equipment is installed in a crawl space
or an attic, the hard−wired carbon monoxide detec-
tor with alarm and battery back−up may be installed
on the next adjacent floor level.
2 − A complete parts list for the venting system design or
venting system.
MANUFACTURER REQUIREMENTS −
GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED.
b − In the event that the requirements of this subdivi-
sion cannot be met at the time of completion of
installation, the owner shall have a period of thirty
(30) days to comply with the above requirements;
provided, however, that during said thirty (30) day
period, a battery−operated carbon monoxide detec-
tor with an alarm shall be installed.
When the manufacturer of Product Approved side wall,
horizontally vented, gas−fueled equipment does not pro-
vide the parts for venting the flue gases, but identifies ꢁspe-
cial venting systems," the following requirements shall be
satisfied by the manufacturer:
2 − APPROVED CARBON MONOXIDE DETECTORS.
Each carbon monoxide detector as required in accor-
dance with the above provisions shall comply with
NFPA 720 and be ANSI/UL 2034 listed and IAS certi-
fied.
1 − The referenced ꢁspecial venting system" instructions
shall be included with the appliance or equipment
installation instructions; and
2
The ꢁspecial venting systems" shall be Product Ap-
proved by the Board, and the instructions for that sys-
tem shall include a parts list and detailed installation
instructions.
3 − SIGNAGE. A metal or plastic identification plate shall
be permanently mounted to the exterior of the building
at a minimum height of eight (8) feet above grade di-
rectly in line with the exhaust vent terminal for the hori-
zontally vented, gas−fueled heating appliance or
equipment. The sign shall read, in print size no less
than one−half (1/2) inch in size, ꢁGAS VENT DIRECT-
LY BELOW. KEEP CLEAR OF ALL OBSTRUC-
TIONS."
A copy of all installation instructions for all Product
Approved side wall, horizontally vented, gas−fueled
equipment, all venting instructions, all parts lists for
venting instructions, and/or all venting design instruc-
tions shall remain with the appliance or equipment at
the completion of the installation.
Page 64
Download from Www.Somanuals.com. All Manuals Search And Download.
|