service and
350MAV
Series G
maintenance procedures
4-WAY MULTIPOISE
FIXED-CAPACITY DIRECT-VENT
CONDENSING GAS FURNACE
Cancels: SP05-47
SP05-52
8-02
WARNING: ELECTRICAL SHOCK, FIRE,
OR EXPLOSION HAZARD
Failure to follow safety warnings exactly could result in
dangerous operation, serious injury, death, or property
damage.
Improper servicing could result in dangerous operation,
serious indury, death, or property damage.
Before servicing, disconnect all electrical power to fur-
nace.
When servicing controls, label all wires prior to discon-
necting. Reconnect wires correctly.
Verify proper operation after servicing.
A93040
WARNING: The ability to properly perform mainte-
nance on this equipment requires certain expertise, me-
chanical skills, tools, and equipment. If you do not
possess these, do not attempt to perform any maintenance
on this equipment other than those procedures recom-
mended in the User’s Manual. FAILURE TO FOLLOW
THIS WARNING COULD RESULT IN POSSIBLE
DAMAGE TO THIS EQUIPMENT, SERIOUS PER-
SONAL INJURY, OR DEATH.
Flushing Collector Box and Drainage
System.......................................................................................6
Servicing Hot Surface Ignitor ..................................................7
Electrical Controls and Wiring.................................................8
Checking Heat Tape Operation
(If Applicable)...........................................................................8
Winterizing................................................................................8
WIRING DIAGRAM.....................................................................9
TROUBLESHOOTING .................................................................9
Status Codes..............................................................................9
Component Test........................................................................9
WARNING: Never store anything on, near, or in contact
with the furnace, such as:
1. Spray or aerosol cans, rags, brooms, dust mops,
vacuum cleaners, or other cleaning tools.
SAFETY CONSIDERATIONS
2. Soap powders, bleaches, waxes or other cleaning
compounds, plastic or plastic containers, gasoline,
kerosene, cigarette lighter fluid, dry cleaning fluids, or
other volatile fluids.
3. Paint thinners and other painting compounds, paper
bags, or other paper products.
Recognize safety information. This is the safety-alert symbol
When you see this symbol on the furnace and in instructions or
manuals, be alert to the potential for personal injury.
.
Understand the signal words DANGER, WARNING, and CAU-
TION. These words are used with the safety-alert symbol. DAN-
GER identifies the most serious hazards which will result in severe
personal injury or death. WARNING signifies hazards which
could result in personal injury or death. CAUTION is used to
identify unsafe practices which would result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
Failure to follow this warning can cause corrosion of
the heat exchanger, fire, personal injury, or death.
NOTE: Read the entire instruction manual before starting the
installation.
This symbol → indicates a change since the last issue.
Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified service
agency personnel should install, repair, or service heating equip-
ment.
TABLE OF CONTENTS
SAFETY CONSIDERATIONS.....................................................1
GENERAL......................................................................................2
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS........2
Untrained personnel can perform basic maintenance functions
such as cleaning and replacing air filters. All other operations must
be performed by trained and qualified service agency personnel.
When working on heating equipment, observe precautions in the
literature, on tags, and on labels attached to or shipped with the
unit and other safety precautions that may apply.
Follow all safety codes including the National Fuel Gas Code
(NFGC) NFPA 54-1999/ANSI Z223.1-1999 in the USA; National
Standard of Canada, Natural Gas and Propane Installation Code
CARE AND MAINTENANCE.....................................................2
Cleaning and/or Replacing Air Filter.......................................3
Blower Motor and Wheel Maintenance...................................3
Cleaning Burners ......................................................................4
Cleaning Heat Exchangers........................................................5
Primary Heat Exchangers....................................................5
Secondary Heat Exchangers................................................6
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WASHABLE
FILTER
IN FURNACE
FILTER
RETAINER
WASHABLE
FILTER
FILTER
SUPPORT
FILTER
RETAINER
WASHABLE FILTER OR
DISPOSABLE MEDIA
FILTER IN FILTER CABINET
WASHABLE FILTER OR
DISPOSABLE MEDIA FILTER
IN FILTER CABINET
A00233
Fig. 4—Filter Installed for Side Inlet
A00232
Fig. 3—Bottom Filter Arrangement
If filter is installed in filter cabinet adjacent to furnace:
1. Turn off electrical supply to furnace.
2. Remove filter cabinet door.
WARNING: Turn off the gas and electrical supplies to
the unit before performing any maintenance or service.
Follow the operating instructions on the label attached to
the furnace. Failure to follow this warning could result in
personal injury or death.
3. Slide filter out of cabinet.
4. If equipped with permanent, washable filter, clean filter by
spraying cold tap water through filter in opposite direction
of airflow. Rinse filter and let dry. Oiling or coating of the
filter is not recommended.
The minimum maintenance that should be performed on this
equipment is as follows:
1. Check and clean or replace air filter each month as needed.
2. Check blower motor and wheel for cleanliness annually.
5. If equipped with factory specified disposable media filter,
replace only with a factory-authorized media filter of the
same size.
3. Check electrical connections for tightness and controls for
proper operation each heating season. Service as necessary.
6. Slide filter into cabinet.
7. Replace filter cabinet door.
4. Check for proper condensate drainage. Clean as necessary.
8. Turn on electrical supply to furnace.
5. Check for blockages in combustion-air and vent pipes
annually.
If filter is installed in furnace blower compartment:
1. Turn off electrical supply to furnace.
2. Remove main furnace door and blower access panel.
3. Release filter retainer wire. (See Figs. 3 or 4.)
4. Slide filter out of furnace.
6. Check burners for cleanliness annually.
CAUTION: Personal injury could result from sharp
metal edges, etc. Use care and wear protective clothing
safety glasses, and gloves when removing parts.
5. Furnaces are equipped with permanent, washable filter(s).
Clean filter by spraying cold tap water through filter in
opposite direction of airflow.
I. CLEANING AND/OR REPLACING AIR FILTER
The air filter arrangement may vary depending on the application
or orientation. Filter could be located in furnace blower compart-
ment or in filter cabinet.
6. Rinse filter and let dry. Oiling or coating filter is not
recommended.
7. Slide filter into furnace.
WARNING: Never operate unit without a filter or with
the blower access panel removed. Failure to follow this
warning could result in a fire or personal injury.
8. Recapture filter retainer wire.
9. Replace blower access panel and main furnace door.
10. Turn on electrical supply to furnace.
II. BLOWER MOTOR AND WHEEL MAINTENANCE
CAUTION: Operating a unit without a filter or with the
blower access door removed could cause damage to the
furnace blower motor. Dust and lint on internal parts of
furnace can cause a loss of efficiency.
To ensure long life, economy, and high efficiency, clean accumu-
lated dirt and grease from blower wheel and motor annually.
The inducer and blower motors are pre-lubricated and require no
additional lubrication. These motors can be identified by the
absence of oil ports on each end of the motor.
NOTE: If the filter has an airflow direction arrow, the arrow must
point toward the blower.
The following items should be performed by a qualified service
technician.
Clean blower motor and wheel as follows:
To clean or replace filters, proceed as follows:
—3—
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1. Turn off electrical supply to furnace.
(2.) Connect 1 tube (violet or unmarked) from inducer
housing.
2. Remove main furnace door and blower access panel.
(3.) Connect 1 tube (relief port, green or pink) from
collector box.
3. Disconnect blower motor wires from furnace control.
Field thermostat connections may need to be disconnected
depending on their length and routing.
c. Connect field drain to condensate trap.
4. Remove control box mounting screws, and position control
box, transformer, and door switch assembly to right side of
furnace casing.
13. Reconnect wires.
Refer to furnace wiring diagram and connect thermostat
leads if previously disconnected. (See Fig. 15.)
5. If condensate trap is located in left- or right-hand side of
furnace casing, proceed to item 6, otherwise remove trap
and tubing as described below (see Fig. 8, top left):
NOTE: Refer to Table 1 for motor speed lead reconnection if
leads were not identified before disconnection.
a. Disconnect field drain connection from condensate trap.
CAUTION: Heating speed selection MUST be adjusted
to provide proper temperature rise as specified on the
rating table. Failure to adjust the heating speed may
shorten heat exchanger life.
b. Disconnect drain and relief port tubes from condensate
trap.
c. Remove condensate trap from blower shelf.
6. Remove screws securing blower assembly to blower shelf
and slide blower assembly out of furnace.
7. Clean blower wheel and motor by using a vacuum with soft
brush attachment. Be careful not to disturb balance weights
(clips) on blower wheel vanes. Do not bend wheel or blades
as balance will be affected.
TABLE 1—SPEED SELECTION
FACTORY
COLOR
SPEED
ATTACHED TO
Black
High
Medium High
Medium Low
Low
Cool
8. If greasy residue is present on blower wheel, remove wheel
from the blower housing and wash it with an appropriate
degreaser. To remove wheel:
Yellow (When Present)
Spare
Blue
Red
Heat
Spare
a. Mark blower wheel location on shaft before disassembly
to ensure proper reassembly.
White
Common
Com
b. Loosen setscrew holding blower wheel on motor shaft.
14. Turn on electrical supply. Manually close blower access
door switch. Use a piece of tape to hold switch closed.
Check for proper rotation and speed changes by perroming
a componenet self-test as shown at the bottom of Service
Label. (See Fig. 17.)
NOTE: Mark blower mounting arms and blower housing so each
arm is positioned at the same hole location during reassembly.
c. Mark blower wheel orientation and cutoff plate location
to ensure proper reassembly.
d. Remove screws securing cutoff plate and remove cutoff
plate from housing.
WARNING: Blower access door switch opens 115-v
power to furnace control. No component operation can
occur. Caution must be taken when manually closing this
switch for service purposes. Failure to follow this warn-
ing could result in personal injury or death.
e. Remove bolts holding motor mounts to blower housing
and slide motor and mounts out of housing. Disconnect
capacitor and ground wire attached to blower housing
before removing motor. Motor mounts need not be
removed from motor.
f. Remove blower wheel from housing.
15. If furnace is operating properly, release blower access door
switch, replace blower access door, and replace main
furnace door.
CAUTION: The blower wheel should not be dropped or
betn as balance will be affected.
III. CLEANING BURNERS
The following items should be performed by a qualified service
technician. If the burners develop an accumulation of light dirt or
dust, they may be cleaned by using the following procedure:
g. Clean wheel per instructions on degreaser cleaner. Do
not get degreaser in motor.
9. Reassemble motor and blower wheel by reversing items 8b
through 8f. Ensure wheel is positioned for proper rotation.
Be sure to attach ground wire. Tighten set-screw to 140 to
160 in.-lb torque.
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
3. Remove burner box cover.
10. Reinstall blower assembly in furnace.
4. Using backup wrench, disconnect gas supply pipe from
furnace gas control valve.
11. Reinstall control box, transformer, and door switch assem-
bly on blower shelf.
CAUTION: Label all wires prior to disconnection when
servicing controls. Wiring errors can cause improper and
dangerous operation.
12. Reinstall condensate trap and tubing if previously removed.
a. Reinstall condensate trap in hole in blower shelf.
b. Connect condensate trap drain tubes. See Fig. 8 or tubing
diagram on main furnace door for proper tube location.
5. Remove wires from gas valve. Note location for reassem-
bly.
NOTE: Ensure tubes are not kinked or pinched, as this will affect
operation.
6. Remove burner box pressure tube from gas valve regulator
fitting.
(1.) Connect 1 tube (blue or blue and white striped)
from collector box.
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7. Remove screws that secure manifold to burner box. (See
Fig. 5.)
WARNING: FIRE OR EXPLOSION HAZARD
Failure to follow the safety warnings exactly could result
in serious injury, death, or property damage.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage, per-
sonal injury, or loss of life.
NOTE: Do not remove burner box from cell panel.
8. Remove manifold, orifices, and gas valve as 1 assembly.
9. Remove screws attaching burner assembly in burner box.
10. Remove burner assembly from burner box.
NOTE: All burners are attached to burner bracket and can be
removed as 1 assembly.
18. Check for gas leaks.
11. Clean burners with soft brush and vacuum.
19. Replace main furnace door.
IV. CLEANING HEAT EXCHANGERS
12. Reinstall manifold, orifice, and gas valve assembly in
burner box. Ensure manifold seal grommet is installed
properly and burners fit over orifices.
The following items should be performed by a qualified service
technician.
13. Reconnect wires to gas valve. Refer to furnace wiring
diagram for proper wire location.
A. Primary Heat Exchangers
If the heat exchangers get an accumulation of light dirt or dust on
the inside, they may be cleaned by the following procedure:
14. Reinstall burner box pressure tube to gas valve regulator
fitting.
NOTE: If the heat exchangers get a heavy accumulation of soot
and carbon, both the primary and secondary heat exchangers
should be replaced rather than trying to clean them thoroughly due
to their intricate design. A build-up of soot and carbon indicates
that a problem exists which needs to be corrected, such as
improper adjustment of manifold pressure, insufficient or poor
quality combustion air, improper vent termination, incorrect size
or damaged manifold orifice(s), improper gas, or a restricted heat
exchanger (primary or secondary). Action must be taken to correct
the problem.
15. Reinstall gas supply pipe to furnace gas control valve using
backup wrench on gas valve to prevent rotation and
improper orientation.
NOTE: Use propane gas resistant pipe dope to prevent gas leaks.
DO NOT use Teflon tape.
WARNING: Gas valve switch MUST be facing forward
or tilted upward. Failure to follow this warning could
result in property damage, personal injury, or death.
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
16. Replace burner box cover.
CAUTION: Label all wires prior to disconnection when
servicing controls. Wiring errors can cause improper and
hazardous operation. .
17. Turn on gas and electrical supplies to furnace.
3. Disconnect wires or connectors to flame rollout switch, gas
valve, igniter, and flame sensor.
4. Disconnect combustion-air intake pipe from intake housing.
5. Remove the pressure switch tube from intake housing.
CELL
PANEL
6. Remove screws attaching intake housing to burner box, and
rotate intake housing away from burner box for removal.
MANIFOLD
MOUNTING
SCREW
7. Using backup wrench, disconnect gas supply pipe from gas
valve.
8. Disconnect pressure tubing from gas valve.
9. Remove 2 screws attaching top filler panel and rotate
upwards to gain access to screws attaching burner box to
cell panel.
10. Remove screws attaching burner box to cell panel. (See Fig.
5.)
NOTE: Burner box cover, manifold, gas valve, and burner
assembly should be removed as 1 assembly.
MANIFOLD
11. Clean heat exchanger openings with a vacuum and a soft
brush. (See Fig. 6.)
GAS VALVE
REGULATOR
FITTING
NOTE: After cleaning, inspect the heat exchangers to ensure they
are free of all foreign objects that may restrict flow of combustion
products.
GAS VALVE
A96304
12. Reverse items 4 through 10 for reassembly.
Fig. 5—Burner Box Assembly
—5—
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PRIMARY HX
INLET OPENINGS
WARNING: FIRE OR EXPLOSION HAZARD
Failure to follow the safety warnings exactly could result
in serious injury, death, or property damage.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage, per-
sonal injury, or loss of life.
17. Check for gas leaks.
18. Replace main furnace door.
B. Secondary Heat Exchangers
NOTE: The condensing side (inside) of the secondary heat
exchangers CANNOT be serviced or inspected. A small number of
bottom outlet openings can be inspected by removing the inducer
assembly. See Flushing Collector Box and Drainage System
section for details on removing inducer assembly.
A96305
V. FLUSHING COLLECTOR BOX AND DRAINAGE
SYSTEM
Fig. 6—Cleaning Inlet Openings of Primary Heat
Exchangers
1. Turn off gas and electrical supplies to furnace.
2. Remove main furnace door.
CAUTION: The ground wire from the gas valve MUST
be attached to the burner box attachment screw. Failure to
attach this ground wire to an adequate casing ground will
cause the furnace control to lock out.
3. Disconnect inducer motor and pressure switch wires or
connectors.
4. Disconnect pressure switch tubes.
5. Disconnect vent pipe from inducer housing outlet by
loosening coupling clamp on inducer outlet.
NOTE: Be sure burner box gasket is installed between burner box
and cell panel. If gasket is damaged, replace it.
6. Disconnect drain tube from inducer housing. (See Fig. 8.)
NOTE: Inspect combustion-air intake housing. If foamed gasket
was removed, check for any damage. If gasket is damaged in any
way, it must be repaired. To repair, remove damaged gasket
section, apply sealant releasing agent such as PAM cooking spray
or equivalent (must not contain corn or canola oil, aromatic or
halogenated hydrocarbons or inadequate seal may occur) to burner
box and apply a small bead of G.E. RTV 162, G.E. RTV 6702, or
Dow-Corning RTV 738 sealant to edge of combustion-air intake
housing. (See Fig. 7.)
7. Remove inducer housing assembly by removing 4 bolts
attaching assembly to cell panel.
8. Flush inside of collector box with water until discharge
from condensate trap is clean and runs freely.
NOTE: Ensure the drain tube disconnected from the inducer
housing is higher than the collector box opening or water will flow
out tube.
9. Inspect inside area of collector box for any pieces of foreign
materials and remove if present.
CAUTION: DO NOT use wire brush or other sharp
object to inspect or dislodge materials in secondary heat
exchangers as failure of the secondary heat exchanger
will occur. Flush with water only.
RTV
PAM
10. Reassemble inducer assembly by reversing items 5-7.
Tighten the vent coupling clamp screw(s) to 15 in.-lb of
torque.
A93087
NOTE: If seal between the inducer housing and the collector box
is damaged in any way, it must be repaired. To repair, apply
sealant releasing agent such as PAM cooking spray or equivalent
(must not contain corn or canola oil, aromatic or halogenated
hydrocarbons which can cause an inadequate seal to occur) to
inducer housing. (See Fig. 10.) Apply a small bead of G.E. RTV
162, G.E. RTV 6702, or Dow-Corning RTV 738 sealant to groove
in collector box.
Fig. 7—Combustion-Air Intake Housing Gasket Repair
13. Refer to furnace wiring diagram and reconnect wires to
rollout switch, gas valve, igniter, and flame sensor.
14. Reconnect pressure switch tubes to gas valve and intake
housing. Refer to tube routing label on main furnace door
for proper tube location. Be sure tubes are not kinked. (See
Fig. 8.)
11. Refer to furnace wiring diagram and reconnect wires to
inducer motor and pressure switches or connectors.
15. Turn on gas and electrical supplies to furnace.
12. Reconnect pressure tubes to pressure switches. See diagram
on main furnace door for proper location of tubes. Be sure
tubes are not kinked. (See Fig. 8.)
16. Check furnace operation through 2 complete heat operating
cycles. Look through sight glass in burner enclosure to
check burners. Burner flames should be clear blue, almost
transparent. (See Fig. 9.)
13. Turn on gas and electrical supplies to furnace.
—6—
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14. Check furnace operation through 2 complete heat operating
cycles. Check area below inducer housing, vent pipe, and
condensate trap to ensure no condensate leaks occur. If
leaks are found, correct the problem.
2. Remove main furnace door.
3. Disconnect igniter wire connection.
4. Check igniter resistance.
a. Using an ohm meter, check resistance across both igniter
leads in connector.
WARNING: FIRE OR EXPLOSION HAZARD
Failure to follow the safety warnings exactly could result
in serious injury, death, or property damage.
b. Cold reading should be between 45 ohms and 90 ohms.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifically
for the detection of leaks to check all connections. A fire
or explosion may result causing property damage, per-
sonal injury, or loss of life.
c. If ohm reading is higher than 110 ohms, igniter is
cracked and must be replaced.
5. Remove igniter assembly.
CAUTION: Allow igniter to cool before removal. Nor-
mal operating temperatures exceed 2000°F.
15. Check for gas leaks.
16. Replace main furnace door.
a. Do not remove igniter from bracket while assembly is in
furnace. Using a 1/4 in. nutdriver, remove screw secur-
ing bracket and igniter assembly to bottom of burner
box. The screw in the bracket is always located toward
outside of burner box. The screw may be hidden by inlet
VI. SERVICING HOT SURFACE IGNITER
The igniter does NOT require annual inspection. Check igniter
resistance before removal.
1. Turn off gas and electrical supplies to furnace.
TUBE ROUTING
Furnace is shipped from factory in upflow configuration. Pressure tube and drain tube routing MUST match the diagrams below.
Condensate Trap on LEFT
Condensate Trap; Factory Installed
Tube location when used in UPFLOW application
Side Optional
in Blower Shelf
BURNER ENCLOSURE
PRESSURE REFERENCE
TUBE ASSEMBLY
BURNER ENCLOSURE
PRESSURE REFERENCE
TUBE ASSEMBLY
(Blower access panel removed)
CAP
CAP
COLLECTOR BOX TUBE
(PINK)
PLUG
PLUG
COLLECTOR BOX TUBE
COLLECTOR BOX TUBE
(GREEN)
(PINK)
COLLECTOR BOX DRAIN
TUBE
COLLECTOR BOX TUBE (GREEN)
(BLUE & WHITE STRIPED)
COLLECTOR BOX DRAIN TUBE
(BLUE & WHITE STRIPED)
INDUCER HOUSING (MOLDED) DRAIN TUBE
(BEHIND COLLECTOR BOX DRAIN TUBE)
CONDENSATE TRAP
COLLECTOR BOX DRAIN TUBE
(BLUE)
COLLECTOR BOX DRAIN TUBE
(BLUE)
FIELD-INSTALLED
FACTORY-SUPPLIED
DRAIN TUBE COUPLING
(RIGHT DRAIN OPTION)
CONDENSATE TRAP
FIELD-INSTALLED
FACTORY-SUPPLIED DRAIN TUBE
COUPLING (LEFT DRAIN OPTION)
INDUCER HOUSING DRAIN TUBE
(VIOLET)
FIELD-INSTALLED
FACTORY-SUPPLIED 1/2-IN.
CPVC STREET ELBOWS (2)
FOR LEFT DRAIN OPTION
FIELD-INSTALLED FACTORY-SUPPLIED
DRAIN TUBE
Condensate Trap on
LEFT Side
Condensate Trap on
RIGHT Side
Tube location when used in DOWNFLOW application
PLUG
COLLECTOR BOX
DRAIN TUBE (BLUE)
PLUGGED END
CAP
CAP
COLLECTOR BOX DRAIN TUBE
(BLUE)
COLLECTOR BOX DRAIN
TUBE
(BLUE & WHITE STRIPED)
COLLECTOR BOX
TUBE (GREEN)
COLLECTOR BOX TUBE
(PINK)
PLUG
COLLECTOR BOX DRAIN TUBE
(BLUE & WHITE STRIPED)
COLLECTOR BOX TUBE
(GREEN)
INDUCER HOUSING DRAIN
TUBE (VIOLET)
COLLECTOR BOX
EXTENSION TUBE
COLLECTOR BOX EXTENSION TUBE
BURNER ENCLOSURE PRESSURE
REFERENCE TUBE ASSEMBLY
COLLECTOR BOX
EXTENSION TUBE
CONDENSATE TRAP
DRAIN TUBE COUPLING
CONDENSATE TRAP
COLLECTOR BOX
TUBE (PINK)
BURNER ENCLOSURE PRESSURE
REFERENCE TUBE ASSEMBLY
DRAIN TUBES ROUTED IN
FRONT OF GAS VALVE
COLLECTOR BOX
EXTENSION DRAIN TUBE
GAS VALVE
INDUCER HOUSING DRAIN TUBE (VIOLET)
Tube location when used on
HORIZONTAL - LEFT application
Tube location when used on
HORIZONTAL - RIGHT application
COLLECTOR BOX DRAIN TUBE
(BLUE)
COLLECTOR BOX DRAIN TUBE
(BLUE & WHITE STRIPED)
COLLECTOR BOX EXTENSION TUBE
COLLECTOR BOX TUBE (PINK)
PLUG
CAP
AUXILIARY "J" BOX RELOCATED HERE
PLUG
COLLECTOR BOX
TUBE (GREEN)
BURNER ENCLOSURE
PRESSURE REFERENCE
TUBE ASSEMBLY
INDUCER HOUSING
DRAIN TUBE
(VIOLET)
CAP
COLLECTOR BOX
BURNER ENCLOSURE
PRESSURE REFERENCE
TUBE ASSEMBLY
EXTENSION TUBE
COLLECTOR BOX
DRAIN TUBE (BLUE)
CONDENSATE TRAP
COLLECTOR BOX
EXTENSION TUBE
COLLECTOR BOX
TUBE (GREEN)
DRAIN TUBE
COUPLING
COLLECTOR BOX TUBE (PINK)
RELOCATE TUBE BETWEEN BLOWER
SHELF AND INDUCER HOUSING FOR
040,060, AND 080 HEATING INPUT
FURNACES
COLLECTOR BOX EXTENSION DRAIN TUBE
COLLECTOR BOX DRAIN TUBE
(BLUE AND WHITE STRIPED)
CONDENSATE TRAP
INDUCER HOUSING DRAIN TUBE (VIOLET)
NOTE:
1. All tubing must be connected securely and routed to avoid kinks and traps.
2. Pressure tubing must always slope away from pressure switch to collector box connection as shown.
3. HORIZONTAL-LEFT installations require the collector box pressure tube to be relocated between the inducer housing and the blower shelf to
prevent a trap.Refer to the Installation Instructions for further details.
324999-201 REV. C
A00308
Fig. 8—Furnace Pressure and Drain Tubing Diagram
—7—
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box or inlet pipe, but can be removed without removing
either. After removing screw, slide igniter and bracket
toward outside of burner box and pull straight out.
8. Turn on gas and electrical supplies to furnace.
9. Verify igniter operation by initiating furnace control self-
test feature or by cycling thermostat.
10. Replace main furnace door.
CAUTION: The igniter is fragile. DO NOT allow it to
hit the side of the burner box opening while removing or
replacing it.
VII. ELECTRICAL CONTROLS AND WIRING
CAUTION: There may be more than 1 electrical supply
to the unit. Check accessories and cooling unit for
additional electrical supplies.
b. Inspect igniter for a white area indicating a crack may be
present. If found, replace igniter.
NOTE: A small crack cannot be seen on a new igniter. After a
period of operation, a white area will be visible around the crack.
The electrical ground and polarity for 115-v wiring must be
maintained properly. Refer to Fig. 11 for field wiring information
and to Fig. 15 for unit wiring information.
c. If replacement is required, replace igniter on igniter
bracket external to furnace to avoid damage as the
silicon portion is very brittle and will easily crack or
shatter.
NOTE: If the polarity is not correct, the STATUS LED on the
furnace control will flash rapidly and prevent the furnace from
operating. The control system also requires an earth ground for
proper operation of the furnace control and flame sensor.
d. To remove igniter from igniter bracket, remove screw
holding igniter ceramic block to bracket and pull ce-
ramic block out of bracket.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on the control center. (See Fig. 11.) Any direct shorts of the 24-v
wiring during installation, service, or maintenance will cause this
fuse to blow. If fuse replacement is required, use ONLY a fuse of
identical size (3 amp). The control LED will flash status code 24
when fuse needs to be replaced.
6. To replace igniter/igniter assembly, reverse items 5a
through 5d.
7. Reconnect igniter wire connection.
With power to the unit disconnected, check all electrical connec-
tions for tightness. Tighten all screws on electrical connections. If
any smoky or burned connections are found, disassemble the
connection, clean all parts, strip wire, and reassemble properly and
securely.
BURNER FLAME
BURNER
Reconnect electrical supply to unit and observe unit through 1
complete operating cycle for proper operation.
VIII. CHECKING HEAT TAPE OPERATION
(IF APPLICABLE)
In applications where the ambient temperature around the furnace
is 32°F or lower, freeze protection measures are required. If heat
tape has been applied, check to ensure it will operate when low
temperatures are present.
CAUTION: If this furnace is to be operated in an
unconditioned space where the ambient temperatures may
be 32°F or lower, freeze protection measures must be
taken. (See Fig. 13.)
MANIFOLD
A89020
Fig. 9—Burner Flame
NOTE: See CONDENSATE DRAIN PROTECTION section of
Installation, Start-Up, and Operating Instructions.
NOTE: Heat tape, when used, should be wrapped around the
condensate drain trap and drain line. There is no need to use heat
tape within the furnace casing. Most heat tapes are temperature
activated, and it is not practical to verify the actual heating of the
tape. Check the following:
PAM
RTV
1. Check for signs of physical damage to heat tape such as
nicks, cuts, abrasions, gnawing by animals, etc.
2. Check for discolored heat tape insulation. If any damage or
discolored insulation is evident, replace heat tape.
3. Check that heat tape power supply circuit is on.
IX. WINTERIZING
CAUTION: Freezing condensate left in the furnace will
damage the equipment.
If the furnace will be off for an extended period of time in a
structure where the temperature will drop to 32° or below,
winterize as follows:
A93081
Fig. 10—Gasket on Collector Box
—8—
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FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
NOTE 2
THERMOSTAT
TERMINALS
W
C
R
G
Y
FIVE WIRE
FIELD-SUPPLIED
DISCONNECT
THREE-WIRE
HEATING-ONLY
208/230- OR
460-V
BLOWER DOOR SWITCH
THREE
PHASE
W
BLK
BLK
WHT
C
R
WHT
O
N
T
208/230-V
SINGLE
PHASE
GND
GND
G
R
AUXILIARY
J-BOX
115-V FIELD-
SUPPLIED
DISCONNECT
O
COM
GND
L
NOTE 1
CONDENSING
UNIT
Y/Y2
TWO
WIRE
24-V
TERMINAL
BLOCK
NOTES: 1. Connect Y-terminal in furnace as shown for proper blower operation.
2. Some thermostats require a "C" terminal connection as shown.
3. If any of the original wire, as supplied, must be replaced, use
same type or equivalent wire.
FURNACE
A99440
Fig. 11—Field Wiring
1. Turn off electrical supply to furnace.
2. Remove main furnace door.
NOTE: Removing the blower access door will open the blower
access door switch and terminate 115-v power to the control.
To read current status code, remove main furnace door. The status
code LED can be viewed through the sight glass on the blower
access door.
3. Disconnect cap from unused drain tap on inducer housing.
(See Fig. 14.)
4. Connect field-supplied 1/2-in. I.D. tube to upper inducer
housing drain connection.
NOTE: NO thermostat signals may be present at control and all
blower off delays must be completed to view previous codes.
5. Insert funnel in drain tube and pour up to 1 quart antifreeze,
propylene glycol (RV, swimming pool antifreeze, or
equivalent) into funnel until it is visible at point where
condensate enters open drain. (See Fig. 15.)
To retrieve previous codes, remove 1 of the red main limit or flame
rollout switch wires for 1 to 4 sec until the LED light goes out, then
reconnect it. (Do not leave red wire disconnected for longer
periods of time as the control will assume an overtemperature
condition exists and will respond with blower operation.) This
places the control in the status recall mode and displays the first
code stored in memory.
6. Reconnect drain cap to inducer housing.
7. Replace main furnace door.
Record the code and repeat the disconnect and reconnect of the red
wire, recording each code until code 11 is displayed indicating no
addition codes. After the last code is displayed or after 2 minutes
in the code recall mode the control will return to normal standby
mode.
CAUTION: Do not use ethylene glycol (Prestone II
antifreeze/coolant or equivalent automotive type). Failure
of plastic components will occur.
8. Propylene glycol need not be removed before restarting
furnace.
B. Component Test
WARNING: Blower access panel door switch opens
115-v power to control center. No component operation
can occur. Caution must be taken when manually closing
this switch for service purposes. Failure to follow this
warning could result in electrical shock, personal injury,
or death.
WIRING DIAGRAM
See Fig. 16 for Wiring Diagram.
TROUBLESHOOTING
Use the Troubleshooting Guide, the status code LED on the
cotntrol and the Component Test to isolate furnace operation
problems.
A. Status Codes
Use the Component Test to check furnace components for proper
operation. To initiate the component self-test sequence, shut off
the room thermostat or disconnect the ″R″ thermostat lead. Briefly
(approximately 2 sec) short the TWIN/TEST terminal to the COM
24V terminal. The status LED will turn off. The test sequence will
be as follows:
For an explanation of status codes, refer to service label located on
back of main furnace door or Fig. 17 and the Troubleshooting
Guide. The stored status codes will NOT be erased from the
control memory if 115- or 24-v power in interrupted. The control
will store up to 7 Status Codes.
—9—
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TWINNING AND/OR
COMPONENT TEST
TERMINAL
BLOWER OFF-DELAY
BLOWER OFF-DELAY
HUMIDIFIER TERMINAL
(24-VAC 0.5 AMP MAX.)
24-V THERMOSTAT
TERMINALS
TRANSFORMER 24-VAC
CONNECTIONS
TEST/TWIN
HUM
0.5 AMP@24VAC
3-AMP FUSE
FUSE 3-AMP
SEC-2 SEC-1
LED OPERATION &
DIAGNOSTIC LIGHT
EAC-2
L2
PL1-LOW VOLTAGE MAIN
HARNESS CONNECTOR
115-VAC(L2)NEUTRAL
CONNECTIONS
COOL
HEAT
1-AMP@
115VAC
FAN
EAC-1
SPARE-1 SPARE-2
PR-1
PL2
1
SPARE-1
SPARE-2
PL2-HOT SURFACE
IGNITER & INDUCER
MOTOR CONNECTOR
115 VAC (L1) LINE
VOLTAGE CONNECTION
FAN
BLOWER SPEED
SELECTION TERMINALS
EAC-1 TERMINAL
(115-VAC 1.0 AMP MAX.)
A02142
Fig. 12— Control Center
1. LED flashes a current status code, or code 11, 4 times.
Record this status code for further troubleshooting.
2. The inducer will start and continue to run until test is over.
3. Hot surface igniter (HSI) is energized for 15 sec, then
de-energized.
4. The blower motor operates on HEATING speed for 10 sec,
then turns off.
5. The blower motor operates on COOLING speed for 10 sec,
then turns off.
32°F MINIMUM INSTALLED
AMBIENT OR FREEZE
PROTECTION REQUIRED
6. Blower operates on continuous fan speed, then turns off.
7. Inducer turns off.
8. The gas valve and humidifier terminal HUM are not
energized for safety reasons.
A93058
Fig. 13—Winterizing the Furnace
—10—
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A99118
Fig. 14—Inducer Housing Drain Tube
A99119
Fig. 15—Funnel in Drain and Antifreeze Running
Through Trap
—11—
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TO 115VAC FIELD DISCONNECT
(WHEN USED)
LGPS
SCHEMATIC DIAGRAM
BLOWER OFF DELAY
JUMPER SELECT
PRS
NOTE #2
L1
(NATURAL GAS & PROPANE)
L2
PCB
GND
EQUIPMENT GROUND
FAN
Y1
ORN
RED
90
120
150
180
J1
DHUM
G
Com
24V
LO
CAP-1
ILK
MED LO
MED HI
HI
NOTE #11
BLU
HEAT
YEL
L1
FAN
BLU
START
SPARE-1
COOL
NOTE #10
L2
OL
HI/LO
W
BLWR
GV
M
EAC-2
RED
Y/Y2
R
TEST/TWIN
HUM
BLWM
ORN
LS
FRS
COM
HSI
C
EAC-1
HSIR
GRN/YEL
NOTE #3
FU1
NOTE #6
RED
GRN/YEL
WHT
1
2
1
2
IDR
IDM
WHT
SEC-1
SEC-2
PL2
PL3
OL
BLU
BLK
WHT
PR1
115VAC
M
AUX
LED 1
EAC-2
RED
RED
RED
WHT
L2
TRAN
1
CAP -2
24VAC
GRN/YEL
3
2
GRN/YEL
PL4
TEST/TWIN
BRN
BRN
PL4
3
CAP - 2
FRS
YEL
WHT
WHT
M
PL1
FSE
BLK
NOTE #6
F U 1
AUX
GRN/YEL
BLK
2
1
IDM
PL2
OL
SEC-1
GVR-2
SEC-2
LS
6
BHT/CLR BFANR
COOL
BLWR
L1
2
1
WHT
PL3
WHT
BLK
2
1
HUM
FAN
HEAT
8
2
BLK
R
LGPS
(WHEN USED)
SPARE 1
EAC-1
SPARE 2
PR1
W
WHT (COM)
PL1
BLK (HI)
WHT
(COM)
NOTE #11
PRS
WHT
BLK
JB
BLWM
FUSED OR CIRCUIT BREAKER
GRN/YEL
CAP -1
DISCONNECT SWITCH (WHEN REQ’D)
YEL
NOTE #2
(MED HI)
BRN
OL
4
WHT
BLK
NEUTRAL
L1
WHT
BLK
FU2
GV
START
GVR-1
NOTE #10
RED (LO)
Y/Y2
10
M
CPU
BLU
(MED LO)
ILK
BRN
GND
DHUM
Y1
C
5
NOTE #3
OL
AUTO-RESET INTERNAL MOTOR OVERLOAD
TEMPERATURE SWITCH (N.C.)
PRINTED CIRCUIT BOARD CONTROL
11-CIRCUIT PCB CONNECTOR
2-CIRCUIT CONNECTOR
2-CIRCUIT HSI, CONNECTOR
3-CIRCUIT IDM EXTENSION CONNECTOR
PRESSURE SWITCH, SPST-(N.O.)
BFANR
BHT/CLR
BLWR
BLWM
CAP 1, 2
CPU
EAC-1
EAC-2
FRS
CONTINUOUS-FAN SELECT RELAY, SPDT
L
1
9
BLOWER MOTOR SPEED CHANGE RELAY, SPDT
BLOWER MOTOR RELAY, SPST-(N.O.)
BLOWER MOTOR, PERMANENT-SPLIT-CAPACITOR
CAPACITOR
G
E
G
E
N
D
PCB
PL1
PL2
PL3
PL4
PRS
FSE
7
3
MICROPROC ESSOR AND C IRCUITRY
COM
PCB
NOTE #5
ELECTRONIC AIR CLEANER CONNECTION (115 VAC 1.0 AMP MAX.)
ELECTRONIC AIR CLEANER CONNECTION (COMMON)
FLAME ROLLOUT SW. -MANUAL RESET, SPST-(N.C.)
FLAME-PROVING ELECTRODE
11
NOTES:
TEST/ TWIN
TRAN
COMPONENT TEST & TWIN TERMINAL
TRANSFORMER-115VAC/24VAC
FSE
FU 1
FU 2
FUSE, 3 AMP, AUTOMOTIVE BLADE TYPE, FACTORY INSTALLED
FUSE OR CIRCUIT BREAKER CURRENT INTERRUPT DEVICE
(FIELD INSTALLED & SUPPLIED)
EQUIPMENT GROUND
GAS VALVE-REDUNDANT
1. If any of the original equipment wire is replaced use wire rated for 105°C.
JUNCTION
2. Use only copper wire between the disconnect switch and the furnace junction box (JB).
3. This wire must be connected to furnace sheet metal for control to prove flame.
4. Symbols are electrical representation only.
UNMARKED TERMINAL
PCB CONTROL TERMINAL
FACTORY WIRING (115VAC)
FACTORY WIRING (24VAC)
FIELD WIRING (115VAC)
FIELD WIRING (24VAC )
CONDUCTOR ON CONTROL PCB
FIELD WIRING SCREW TERMINAL
FIELD EARTH GROUND
EQUIPMENT GROUND
FIELD SPLICE
GND
GV
GVR 1, 2
HSI
HSIR
HUM
IDM
IDR
ILK
J1
JB
LED
LGPS
LS
5. Solid lines inside PCB are printed circuit board conductors and are not included in legend.
6. Replace only with a 3 amp fuse.
7. Inducer (IDM) and blower (BLWM) motors contain internal auto-reset thermal overload switches (OL).
8. Neutral connections are interchangeable within the NEUTRAL connector block.
9. Blower motor speed selections are for average conditions, see installation instructions for details on
optimum speed selection.
GAS VALVE RELAY, DPST-(N.O.)
HOT SURFACE IGNITER (115 VAC)
HOT SURFACE IGNITER RELAY, SPST-(N.O.)
24VAC HUMIDIFIER CONNECTION (0.5 AMP. MAX.)
INDUCED DRAFT MOTOR, PSC
INDUCED DRAFT MOTOR RELAY, SPST-(N.O.)
BLOWER ACCESS PANEL INTERLOCK SWITCH, SPST-(N.O.)
BLOWER - OFF DELAY JUMPER SELECTOR
JUNCTION BOX
LIG HT-EMITTING DIODE FOR STATUS CODES - AMBER
LOW GAS PRESSURE SWITCH, SPST-(N.O.)
LIMIT SWITCH, AUTO-RESET, SPST (N.C.)
10. YELLOW lead not on all motors.
11. Factory connected when LGPS is not used.
12. Ignition-lockout will occur after four consecutive unsuccessful trials-for-ignition. Control will
auto-reset after three hours.
13. Blower-on delay: gas heating 60 seconds, cooling or heat pump 2 seconds.
14. Blower-off delay: gas heating selections are 90, 120, 150 or 180 seconds, cooling or heat pump
90 seconds or 5 seconds when dehumidify call is active.
PLUG RECEPTACLE
326796-101 REV. A
Fig. 16—Wiring Diagram
A02157
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SERVICE
If status code recall is needed, briefly remove then reconnect one main limit wire to display
stored status code. On RED LED boards do not remove power or blower door before initiat-
ing status code recall. After status code recall is completed component test will occur.
LED CODE
STATUS
CONTINUOUS OFF - Check for 115VAC at L1 & L2, & 24VAC at SEC-1 & SEC-2.
CONTINUOUS ON - Control has 24VAC power.
RAPID FLASHING - Line voltage (115VAC) polarity reversed. If twinned,
refer to twinning kit instructions.
EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH THE FIRST
DIGIT DETERMINED BY THE NUMBER OF SHORT FLASHES AND THE SECOND DIGIT BY
THE NUMBER OF LONG FLASHES.
11 NO PREVIOUS CODE - Stored status code is erased automatically after 72
hours. On RED LED boards stored status codes can also be erased when power
(115 VAC or 24 VAC) to control is interrupted.
12 BLOWER ON AFTER POWER UP (115 VAC or 24 VAC) -Blower runs for 90
seconds, if unit is powered up during a call for heat (R-W closed) or R-W opens
during blower on-delay.
13 LIMIT CIRCUIT LOCKOUT - Lockout occurs if the limit or flame rollout switch is
open longer than 3 minutes.
- Control will auto reset after three hours.
- Refer to #33.
14 IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34.
21 GAS HEATING LOCKOUT - Control will NOT auto reset.
Check for: - Mis-wired gas valve
-Defective control (valve relay)
22 ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas valve is
de-energized. Inducer will run until fault is cleared. Check for:
- Leaky gas valve
- Stuck-open gas valve
23 PRESSURE SWITCH DID NOT OPEN Check for:
- Obstructed pressure tubing.
- Pressure switch stuck closed.
24 SECONDARY VOLTAGE FUSE IS OPEN Check for:
- Short circuit in secondary voltage (24VAC) wiring.
31 PRESSURE SWITCH DID NOT CLOSE OR REOPENED - If open longer than
five minutes, inducer shuts off for 15 minutes before retry. Check for:
- Excessive wind - Proper vent sizing
- Low inducer voltage (115VAC)
- Inadequate combustion air supply
- Disconnected or obstructed pressure tubing
- Low inlet gas pressure (if LGPS used)
- Defective inducer motor
- Defective pressure switch
- Restricted vent
If it opens during blower on-delay period, blower will come on for the selected
blower off-delay.
33 LIMIT CIRCUIT FAULT - Indicates a limit, or flame rollout is open. Blower will
run for 4 minutes or until open switch remakes whichever is longer. If open
longer than 3 minutes, code changes to lockout #13. If open less than 3 minutes
status code #33 continues to flash until blower shuts off. Flame rollout switch
requires manual reset. Check for: - Restricted vent
- Proper vent sizing
- Loose blower wheel
- Excessive wind
- Dirty filter or restricted duct system.
- Defective blower motor or capacitor. - Defective switch or connections.
- Inadequate combustion air supply (Flame Roll-out Switch open).
34 IGNITION PROVING FAILURE - Control will try three more times before lockout
#14 occurs. If flame signal lost during blower on-delay period, blower will come
on for the selected blower off-delay. Check for: - Control ground continuity
- Flame sensor must not be grounded
- Oxide buildup on flame sensor (clean with fine steel wool).
- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal).
- Gas valve defective or gas valve turned off
- Defective Hot Surface Ignitor
- Manual valve shut-off
- Low inlet gas pressure
- Inadequate flame carryover or rough ignition
- Green/Yellow wire MUST be connected to furnace sheet metal
45 CONTROL CIRCUITRY LOCKOUT Auto-reset after one hour lockout due to;
- Gas valve relay stuck open
- Software check error
- Flame sense circuit failure
Reset power to clear lockout. Replace control if status code repeats.
COMPONENT TEST
To initiate the component test sequence, shut OFF the room thermostat or disconnect
the "R" thermostat lead. Briefly short the TEST/TWIN terminal to the "Com 24V" ter-
minal. Status LED will flash code and then turn ON the inducer motor. The inducer
motor will run for the entire component test. The hot surface ignitor, blower motor
FAN speed (AMBER LED boards only) blower motor HEAT speed, and blower motor
COOL speed will be turned ON for 10-15 seconds each. Gas Valve and Humidifier
will not be turned on.
327884-101 REV. A
A02154
Fig. 17—Service Label
—13—
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TROUBLESHOOTING GUIDE
START
Is LED status light on?
NO
NO
NO
NO
Is there 115V at L1 and L2?
Is door switch closed?
Close door switch and go back to START.
YES
YES
YES
Is there 115V going to switch?
YES
NO
Is there 24V at SEC-1 and SEC-2?
YES
Is circuit breaker closed?
YES
NO
Replace furnace control.
Replace door switch.
Check for continuity in wire from circuit breaker
to furnace.
Check for correct line voltage polarity. If units
are twinned, check for proper low-voltage
(24V) transformer phasing.
YES
NO
Replace transformer.
Close circuit breaker and go back to START.
Is LED status light blinking rapidly without a
pause?
NO
To recall status code briefly remove and reconnect one RED wire from the Limit
Switch or Flame Rollout switch to display stored status code. On RED LED
control do not remove power or blower access panel before initiating status
code recall. You can also recall the previous status code by momentarily shorting
the TEST/TWIN terminal to Com24V terminal until the LED goes out. LED will
flash the previous status code or status code #11 (1 short and 1 long flash) if
there was no previous code. After the control repeats the code 4 times, the
control will go through a brief component test sequence. The inducer will start
and run for the entire component test. The HSI, blower motor FAN speed
(AMBER LED boards only) HEAT speed, and COOL speed will run for 10 – 15
seconds each. Gas valve and humidifier will not be turned on.
Is LED status light blinking ON/OFF slowly
with a combination of short and long flashes?
YES
Determine status code. The status code is a
2 digit number with the first digit determined
by the number of short flashes and the second
digit by the number of long flashes?
Check room thermostat or
interconnecting cable.
NO
YES
NO
Does the control respond to W,Y1 (if present),
Y/Y2, and G (24V) thermostat signals?
Is 24V present at W, Y1 (if present), Y/Y2 or
G thermostat terminals on the furnace control?
Was there a previous status code
other than #11?
NO
Go to section below for the status code that
was flashed.
YES
YES
Run system through a heating or cooling cycle
to check operation. Status codes are erased
after 72 hours. On RED LED boards stored
status codes can also be erased whenever
(115V or 24V) is interrupted.
Disconnect all the thermostat wires from the
furnace control.
YES
Does the problem repeat when using
a jumper wire?
Replace furnace control.
NO
The thermostat is not compatible with the
furnace control. Either install a ballast resistor,
connect the Com24V thermostat terminal to
the thermostat, or replace the thermostat.
A02204a
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11 NO PREVIOUS CODE – Stored codes
are erased after 72 hours. On RED LED
boards stored status codes can also be
erased whenever power (115V or 24V)
is interrupted. Run system through a
heating or cooling cycle to check system.
31 PRESSURE SWITCH DID NOT CLOSE
OR REOPENED – If open longer than 5
minutes, inducer shuts off for 15 minutes
before retry. If opens during blower on-
delay period, blower will come on for the
selected blower off-delay. Check for:
45 CONTROL CIRCUITRY LOCKOUT
Auto-reset after 1 hour lockout due to:
-
Flame circuit failure.
Gas valve relay stuck open.
-
-
Software check error.
Reset power to clear lockout. Replace
control if code repeats.
-
-
-
-
-
Proper vent sizing.
Low inducer voltage (115V).
Low inlet gas pressure (if LGPS used).
Inadequate combustion air supply.
Disconnected or obstructed pressure
tubing.
12 BLOWER ON AFTER POWER UP –
(115V OR 24V) – Normal operation.
Blower runs for 90 seconds, if unit is
powered up during a call for heat (R-W
closed) or when (R-W opens) during the
blower on-delay period.
NO
Unplug igniter harness from control and initiate
another component test sequence. Check
for 115V between pin 1 and NEUTRAL-L2 on
the control. Was 115V present for the 15
second period?
Replace furnace control.
-
-
-
-
Defective inducer motor.
Defective pressure switch.
Excessive wind.
YES
NO
Check for continuity in the harness and igniter.
Replace defective component.
Restricted vent.
13 LIMIT CIRCUIT LOCKOUT – Lockout
occurs if the limit or flame rollout switch is
open longer than 3 minutes. Control will
auto-reset after 3 hours. See code 33.
33 LIMIT CIRCUIT FAULT – Indicates the
limit or flame rollout switch is open. Blower
will run for 4 minutes or until open switch
remakes whichever is longer. If open
longer than 3 minutes, code changes to
lockout #13. If open less than 3 min.
status code #33 continues to flash until
blower shuts off. Flame rollout switch
requires manual reset. Check for:
Reconnect the R thermostat lead and set
thermostat to call for heat. Connect voltmeter
across gas valve connections. Does gas valve
receive 24V?
Check connections. If OK, replace control.
Check that all gas valves are turned on.
Replace valve.
YES
14 IGNITION LOCKOUT – System failed to
ignite gas and prove flame in 4 attempts.
Control will auto-reset after 3 hours.
See status code 34.
Does gas valve open and allow gas to flow?
Check for:
NO
NO
-
Inadequate flame carryover or rough
ignition.
-
-
-
-
-
Dirty filter or restricted duct system.
Loose blower wheel.
YES
-
-
-
Low inlet gas pressure.
Proper firing rate.
Check for air leakage around igniter bracket.
Defective switch or connections.
Defective blower motor or capacitor.
Inadequate combustion air supply
(flame rollout switch open).
Restricted vent.
Do the main burners ignite?
21 GAS HEATING LOCKOUT – Turn off
power and wait 5 minutes to retry.
Check for:
YES
Do the main burners stay on?
NO
-
-
-
YES
NO
Proper vent sizing.
Excessive wind.
-
-
Stuck closed gas valve relay on control.
Miswire or short to gas valve wire.
Allow blower to come on and repeat test to
check for intermittent operation.
- Blower motor on incorrect speed tap.
- Input rate to furnace set too high.
22 ABNORMAL FLAME-PROVING SIGNAL
Flame is proved while gas valve is de-
energized. Inducer will run until fault is
cleared. Check for:
Check connections and retry. If current is
near typical value (4.0-6.0 nominal) and
burners will not stay on, replace control.
Repeat call for heat and check flame sensor
current during trial for ignition period. Is the
DC microamps below 0.5?
34 IGNITION PROVING FAILURE – If flame
is not sensed during the trial for ignition
period, the control will repeat the ignition
sequence 3 more times before lockout
#14 occurs. If flame signal is lost during
the blower on-delay period, blower will
come on for the selected blower off-delay.
Check the following items first before
proceeding to the next step.
-
Stuck open or leaky gas valve.
NO
YES
YES
23 PRESSURE SWITCH DID NOT OPEN
Check for:
Clean flame sensor with fine steel wool and
recheck current. Nominal current is 4.0 to 6.0
microamps.
-
-
Obstructed pressure tube.
Pressure switch stuck closed.
-
-
-
Gas valve turned off.
Manual shut-off valve.
Green/Yellow wire MUST be connected
to furnace sheet metal.
24 SECONDARY VOLTAGE FUSE IS OPEN
Check for:
-
Short circuit in secondary voltage (24V)
wiring including thermostat leads.
Disconnect thermostat leads to isolate
short circuit.
-
Flame sensor must not be grounded.
NO
NO
Is current near typical value?
Replace electrode.
To determine whether the problem is in
the gas valve, igniter, or flame sensor the
system can be operated in the component
test mode to check the igniter. First
remove the R thermostat connection from
the control and initiate the component
test sequence. Does the igniter glow
orange/white by the end of the 15 second
warm-up period?
YES
Will main burners ignite and stay on?
Replace furnace control.
YES
Fixed.
A02204b
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© 2002 Bryant Heating & Cooling Systems 7310 W. Morris St. Indianapolis, IN 46231
Printed in U.S.A.
sp0558
Catalog No. 5335-207
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