FOR YOUR SAFETY
If you smell gas:
1. Open windows.
®
2. DO NOT try to light any appliance.
3. DO NOT use electrical switches.
4. DO NOT use any telephone in
your building.
Combat
5. Leave the building.
6. Immediately call your local gas
supplier after leaving the building.
Follow the gas supplier’s
instructions.
7. If you cannot reach your gas
supplier, call the Fire Department.
UHA-Series
Tubular Unit Heaters
(Standard Range)
WARNING
Installation, Operation
& Service Manual
Models UHA[S]
150, 175, 200, 225
250, 300, 350, 400
Fire Hazard
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
Some objects will catch fire or explode
when placed close to heater.
Failure to follow these instructions can
result in death, injury or property
damage.
WARNING
Installer
Improper installation, adjustment, alteration, service
or maintenance can result in death, injury or property
damage. Read the Installation, Operation and Service
Manual thoroughly before installing or servicing
this equipment.
Please take the time to read and understand
these instructions prior to any installation.
Installer must give a copy of this manual to the owner.
Owner
Installation must be done by a contractor qualified
in the installation and service of gas-fired heating
equipment or your gas supplier.
Keep this manual in a safe place in order to provide
your serviceman with necessary information.
Roberts-Gordon, LLC
1250 William Street
P.O. Box 44
Buffalo, New York 14240-0044
Telephone: 716.852.4400
Fax: 716.852.0854
Toll Free: 800.828.7450
Quality in Any Language™
© Copyright 2007 Roberts-Gordon, LLC
P/N 111101NA 10/07 Rev. D
TABLE OF CONTENTS
SECTION 1: Heater Safety......................................................1 SECTION 11: User Instructions............................................22
SECTION 3: Critical Considerations .....................................3 SECTION 12: Servicing.........................................................24
3.9 Separated Combustion Installation..............................3 SECTION 13: Troubleshooting .............................................27
13.2 Troubleshooting For Automatic Ignition Burner
Systems...................................................................28
4.6 High Altitude ................................................................5 SECTION 14: Replacement Parts.........................................31
6.5 Vertical Venting............................................................8 SECTION 15: Specifications.................................................37
15.1 Standard (Models 150 - 400) UHA(S) Series
Dimension Data .........................................................37
7.2 Unvented Installation.................................................. 13 SECTION 16: The ROBERTS GORDON® COMBAT®
UHA-Series Warranty.....................................39
© 2007 Roberts-Gordon, LLC
All rights reserved. No part of this work covered by the copyrights herein may be reproduced
or copied in any form or by any means - graphic, electronic, or mechanical, including
photocopying, recording, taping or information storage and retrieval systems - without the
written permission of Roberts-Gordon, LLC.
Printed in U.S.A.
TABLE OF FIGURES
Figure 1: Installation Clearances and Clearances to
Combustibles.............................................................4
Figure 4: Standard Vented Heater - Vertical and
Horizontal Vent Termination ......................................9
Figure 5: Standard Vented Heater - Common Vertical Vent
Termination.............................................................. 10
Figure 6: Separated Combustion Heater - Vertical and
Horizontal Vent Termination .................................... 11
Figure 8: Concentric Vertical and Horizontal Vent
Termination - Separated Combustion Heater........... 12
SECTION 1: HEATER SAFETY
SECTION 1: HEATER SAFETY
Your Safety is Important to Us!
This symbol is used throughout
the manual to notify you of
possible fire, electrical or burn
hazards. Please pay special
attention when reading and
following the warnings in these
sections.
Installation, Service and Annual
Inspection of heater must be done by a contractor
qualified in the installation and service of gas-fired
heating equipment.
Read this manual carefully before installation,
operation or service of this equipment.
Heaters are not approved for residential installation.
These instructions, the layout drawing, local codes
and ordinances and applicable standards that apply
to gas piping, electrical wiring, venting, etc. must be
thoroughly understood before proceeding with the
installation.
Thin sheet metal parts, including the various venting
components, have sharp edges. To prevent injury,
the use of work gloves is recommended.
Before installation, check that the local distribution
conditions, nature of gas and pressure and
adjustment of the appliance are compatible.
1.1 Manpower Requirements
To prevent personal injury and damage to the
heater, two persons will be required for installation.
1
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
SECTION 2: INSTALLER RESPONSIBILITY
The installer is responsible for the following:
2.2 Corrosive Chemicals
• To install the heater, as well as the gas and
electrical supplies, in accordance with applicable
specifications and codes. Roberts-Gordon
recommends the installer contact a Local
Building Inspector or Fire Marshal for guidance.
CAUTION
Do not use heater in an area containing corrosive
chemicals.
Avoid the use of corrosive chemicals to ensure a
longer life of the burner, heat exchanger and other
parts.
• To use the information given in a layout drawing
and in the manual together with the cited codes
and regulations to perform the installation.
Failure to follow these instructions can result in
property damage.
• To install the heater in accordance with the
clearances to combustibles.
Roberts-Gordon cannot be responsible for ensuring
that all appropriate safety measures are undertaken
prior to installation; this is entirely the responsibility
of the installer. It is essential that the contractor, the
sub-contractor, or the owner identifies the presence
of combustible materials, corrosive chemicals or
halogenated hydrocarbons* anywhere in the
premises.
• To furnish all needed materials not furnished as
standard equipment.
• To plan location of supports, vents and air
intakes.
• To provide access for servicing.
• To provide the owner with a copy of this
Installation, Operation and Service Manual.
• To never use heater as support for a ladder or
other access equipment and never hang or
suspend anything from heater.
* Halogenated Hydrocarbons are a family of chemical
compounds characterized by the presence of halogen ele-
ments (fluorine, chlorine, bromine, etc.). These compounds are
frequently used in refrigerants, cleaning agents, solvents, etc. If
these compounds enter the air supply of the burner, the life
span of the heater components will be greatly reduced. An out-
side air supply must be provided to the burners whenever the
presence of these compounds is suspected. Warranty will be
invalid if the heater is exposed to halogenated hydrocarbons.
• To ensure there is adequate air circulation
around the heater and to supply air for
combustion, ventilation and distribution in
accordance with local codes.
2.3 National Standards and Applicable Codes
2.1 Wall Tag
All appliances must be installed in accordance with
the latest revision of the applicable standards and
national codes. This refers also to the electric, gas
and venting installation. Note: Additional standards
for installations in public garages, aircraft hangars,
etc. may be applicable.
A laminated wall tag is included with the heater as a
permanent reminder of the safety instructions and
the importance of the required clearances to
combustibles. Affix the tag by peeling off the backing
of the adhesive strips on the rear surface and
position the tag on a wall near the heater.
A copy of the wall tag (P/N 91040031) is illustrated
on the back cover.
Know your model number. Model number is found
on the heater and in the Installation, Operation and
2
SECTION 3: CRITICAL CONSIDERATIONS
SECTION 3: CRITICAL CONSIDERATIONS
3.1 Basic Information
3.7 Electrical Supply
UHA(S) heaters have automatic ignition burners for A permanent 120 V 60 Hz 1 Ø electrical supply is
ON/OFF operation only.
required for the main electrical power. The heater
also requires suitable controls in accordance with
3.2 Location and Suspension
All models:
• Must be installed indoors.
3.8 Vent
Choose heater orientation to allow for the proper
location of the vent. Each heater must be fitted with
a correctly sized sealed vent system.
If vented horizontally, no other appliance may be
• Must be installed in a level position with
horizontal discharge.
• May be mounted on a shelf of non-combustible
material.
Figure 2) or from wall brackets of sufficient
strength to support the heater as listed in the
Drop rods must be a minimum of 3/8" diameter
mild steel. Four suspension points (3/8" nuts)
are located on top of the heater.
3.9 Separated Combustion Installation
For separated combustion installation, the vent and
air intake must be fitted with an individual and
correctly sized sealed system and the vent and air
intake must terminate at approved wall and roof
terminals.
• Must be installed in a manner which allows
access to all serviceable components.
See Page 4, Figure 1 for details.
Separated combustion units may not be common
3.3 Minimum Required Installation Clearances
Clearances around the heater and vent must be as
through Page 12, Figure 8 to ensure access for
servicing, and correct operation.
3.4 Clearances to Combustibles
Clearances must be as indicated on Page 4, Figure
1. If clearances to combustibles are not indicated,
then installation clearances apply.
3.5 Ventilation
It is important to ensure that there is adequate air
space around the heater to supply air for
combustion, ventilation and distribution in
accordance with local and national codes.
3.6 Gas Supply
It is important that the gas supply pipe is sized
correctly to provide the inlet pressure as stated on
the heater data plate. The gas supply pipe and
electrical connections must not support any of the
heater's weight.
3
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
WARNING
Fire Hazard
Some objects will catch fire or explode when placed
close to heater.
Keep all flammable objects, liquids and vapors the
required clearances to combustibles away from heater.
Failure to follow these instructions can result in death,
injury or property damage.
Figure 1: Installation Clearances and Clearances to Combustibles
Installation Clearances
Clearances to Combustibles
Roof Terminal
(Optional separated
combustion concentric
venting shown.)
6"
(15 cm)
Top
31"
(79 cm)
6"**
(15 cm)
10'
(3 m)
24" for
Wall
Terminal
adequate
air flow access
axial fan.
3"
20' (6.0 m) - 30' (9.1 m)
Max. Mounting Height*
* Recommended mounting height varies with heater input.
Heaters may be mounted at a higher level if destratification
Clearance to Vent: 2" (5 cm)
fans are installed.
Note: Venting directly from top of heater not applicable
on Models 150 - 400.
**31" (79 cm) minimum is necessary
for servicing.
The heater must always be installed at least 6' (2 m) above the floor.
The vent pipe must have clearance from combustibles by 2" (5 cm).
If installed at low levels where individuals can come in contact with hot heat
exchanger components, adequate guarding must be provided.
4
SECTION 4: NATIONAL STANDARDS AND APPLICABLE CODES
SECTION 4: NATIONAL STANDARDS AND APPLICABLE CODES
4.1 Gas Codes
4.3 Parking Structures and Repair Garages
The type of gas appearing on the nameplate
must be the type of gas used. Installation must
comply with national and local codes and
requirements of the local gas company.
Installation in garages must be in accordance
with the following codes:
United States: Standard for Parking Structures
NFPA 88A - latest revision or the Code for Motor
Fuel Dispensing Facilities and Repair Garages,
NFPA 30A - latest revision. Canada: Refer to
CSA B149.1 Natural Gas and Propane
Installation Code.
United States: Refer to NFPA 54/ANSI Z223.1 -
latest revision, National Fuel Gas Code.
Canada: Refer to CSA B149.1 Natural Gas and
Propane Installation Code.
• In accordance with the Standard for Parking
Structures NFPA 88A, heaters must be located
a minimum of 18" (50 cm) below the floor-ceiling
assembly or 18" (50 cm) above the floor.
4.2 Aircraft Hangars
Installation in aircraft hangars must be in
accordance with the following codes:
• In accordance with the Code for Motor Fuel
Dispensing Facilities and Repair Garages,
NFPA 30A - latest revision, heaters must not be
installed less than 8' (2.4 m) above the floor.
United States: Refer to Standard for Aircraft
Hangars, NFPA 409 - latest revision.
Canada: Refer to Standard CSA B149.1 Natural
Gas and Propane Installation Code.
4.4 Electrical
• In aircraft storage and servicing areas, heaters
shall be installed at least 10' (3 m) above the
upper surface of wings or of engine enclosures
of the highest aircraft which may be housed in
the hangar. The measurement shall be made
from the wing or engine enclosure (whichever is
higher from the floor) to the bottom of the heater.
The heater must be electrically grounded in
accordance with the following codes:
United States: Refer to National Electrical
Code®, NFPA 70 - latest revision. Wiring must
conform to the most current National Electrical
Code®, local ordinances and any special
diagrams furnished.
• In shops, offices and other sections of aircraft
hangars communicating with aircraft storage or
servicing areas, heaters shall be installed not
less than 8' (2.4 m) above the floor.
Canada: Refer to Canadian Electrical Code,
CSA C22.1 Part 1 - latest revision.
• Suspended or elevated heaters shall be so
located in all spaces of aircraft hangars that they
shall not be subject to injury by aircraft, cranes,
movable scaffolding or other objects. Provisions
shall be made to assure accessibility to
suspended heaters for recurrent maintenance
purposes.
4.5 Venting
The venting must be installed in accordance
with the requirements within this manual and
the following codes:
United States: Refer to NFPA 54/ANSI Z223.1 -
latest revision, National Fuel Gas Code.
Canada: Refer to CSA B149.1 Natural Gas and
Propane Installation Code.
4.6 High Altitude
These heaters are approved for installations up
to 2000' (610 m) (US), 4500' (1370 m) (Canada)
without modification. Consult factory if US
installation is above 2000' (610 m) or Canadian
installation is above 4500' (1370 m).
5
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
SECTION 5: MAJOR COMPONENTS
5.1 General
Heaters are designed for installation above 6'
(1.8 m). These heaters must be installed within the
heated space. Duct delivery systems are not
permitted with axial fan units. When handling or
supporting the heater from below, ensure that the
weight is taken at the support points.
5.2 Suspension
WARNING
Crush Hazard
Use 3/8" threaded rod
minimum.
Failure of the supports can
result in death, injury
or property damage.
Figure 2: Suspension Methods
Ensure all suspension
hardware is torqued to
a minimum of 20 ft lbs.
Unistrut
Channel Nut
Washer
Nut
3/8"
Threaded
Rod
Cone Point
Set Pin
Window
Clamp
3/8"
Threaded
Rod
Unistrut
Nut
Washer
Riv
Nut
Support Points
6
SECTION 6: VENTING
SECTION 6: VENTING
6.1 Venting
mechanical air supply inlet to any building.
The vent shall not terminate within 3' (.9 m) of a
This heater must be vented in accordance with the
rules contained in this manual and with the following window or door that can be opened in any building,
national codes and any state, provincial or local
codes which may apply: United States: Refer to
NFPA 54/ANSI Z223.1 - latest revision, National
Fuel Gas Code; Canada: Refer to CSA B149.1
Natural Gas and Propane Installation Code.
Any portion of vent pipe passing through a
combustible wall must have an listed thimble to
conform with the above codes.
any non-mechanical air supply inlet to any building,
or of the combustion air inlet of any other appliance.
6.2 Vent Installation
WARNING
The heater may be installed unvented in
certain circumstances according to building
ventilation codes. Refer to the above codes and
Page 8, Section 6.3 for further information.
Unvented operation also requires compliance with
the clearances to combustibles given on Page 4,
Fire Hazard
Some objects will catch fire or explode when placed
close to heater.
Keep all flammable objects, liquids and vapors the
required clearances to combustibles away from heater.
The bottom of the vent or air intake terminal shall not
be located less than 1' (.3 m) above grade level.
Failure to follow these instructions can result in death,
injury or property damage.
The vent shall not terminate less than 7' (2.1 m)
above grade where located adjacent to public
walkways.
For vented units, the vent must terminate outside of
the building.
Vent terminal must be installed at a height sufficient
to prevent blockage by snow and building materials
protected from degradation by flue gasses.
Vents must be fully sealed and correctly sized for
the model. If the vent passes through a wall or
ceiling of combustible material, it must be enclosed
by a listed thimble and be separated from the
thimble by at least a 2" (5 cm) air gap.
Vent terminal must be beyond any combustible
overhang.
For separated combustion models, vents and air
intakes must be a fully sealed system and correctly
sized for the model. Vent should be assembled as
Figure 8. The joints between the vent terminal and
the roof or wall must be properly sealed. If the vent
passes through a wall or ceiling of combustible
material, it must be enclosed by a listed thimble and
be separated from the thimble by at least a 2" (5 cm)
air gap.
Secure all joints with corrosion resistant #8 x 3/8"
sheet metal screws.
For single wall venting, pressure sensitive aluminum
tape or silicone sealant must be used to seal all
joints.
Aluminum tape shall have a minimum temperature
rating of 400° F (204° C) and meet SMACNA AFTS-
100-73 standards. High temperature silicone
sealant must have a minimum temperature rating of
480° F (250° C).
Vents and air intakes must be adequately
supported so that the heater does not bear the
weight of the pipes.
6.1.1 United States Requirements
Vent must terminate at least 3' (.9 m) above any
forced air inlet located within 10' (3.1 m).
Vent must terminate at least 4' (1.2 m) below,
4' (1.2 m) horizontally from, or 1' (.3 m) above any
door, operable window, or gravity air inlet into any
building.
6.2.1 Standard Vented Heaters
(Models UHA 150 - 400)
NFPA 54/ANSI Z223.1 - latest revision, National
Fuel Gas Code specifies a 4' (1.2 m) horizontal vent
terminal clearance from gas and electric meters,
regulators and relief equipment.
The vent must be fitted with a low resistance
Figure 4. Standard vented heaters do not allow
outdoor air intake for combustion air.
6.1.2 Canadian Requirements
The vent shall not terminate within 6' (1.8 m) of a
7
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
6.2.2 Separated Combustion Heaters
(Models UHAS 150 - 400)
6.5 Vertical Venting
Vertically vented heaters can be common vented
(up to 4 heaters).
The heaters are designed to be installed as
separated combustion heaters. The vent and air
intake are run as separate pipes to the wall or roof
vent and air intake are run as separate pipes to a
concentric vent box and a concentric vent/air intake
pipe penetrates the wall or roof.
For vent lengths greater than 5' (1.5 m),
condensation will form. Insulation is recommended
and condensation drains may be desired. Vent from
the rear of the heater cabinet then run the vent
vertically and use a condensate drain at the bottom
of the vertical vent.
Vent pipe must be sloped 1/4'' (.6 cm) for every
1' (.3 m).
6.3 Unvented Operation
For 4'' (10 cm), an approved vent cap
(P/N 90502102) must be used.
WARNING
Carbon Monoxide Hazard
For 6'' (15 cm) common vent, an approved vent cap
(P/N 90502103) must be used.
Heaters installed unvented must
be interlocked with sufficient
building exhaust.
For common vertical venting of more than two
Heaters must be installed
according to the installation
manual.
A vent shall not extend less than 2' (.6m) above the
highest point where it passes through a flat roof of a
building.
Failure to follow these
instructions can result in death
or injury.
6.6 Length Requirements
For unvented operation in commercial installations,
sufficient ventilation must be provided in the amount
of 4 cfm per 1000 Btu/h firing rate (United States); 3
cfm per 1000 Btu/h firing rate (Canada).
If using vent lengths greater than 5' (1.5 m),
condensation will form in the vent pipe. Insulation
and additional sealing measures (high temperature
silicone at all seams) are required.
The entire vent should be insulated with foil faced
fiberglass insulation (1/2" thick, 1-1/2# density
minimum).
WARNING: Combustion by-products contain a
chemical known to the State of California to cause
cancer and birth defects or other reproductive
harm.
Maximum Vent Lengths Table
Model UHA(S)
# of Elbows
150 - 400
40 ft (12.2 m)
35 ft (10.7 m)
30 ft (9.1 m)
25 ft (7.6 m)
20 ft (6.1 m)
1
2
3
4
5
6.4 Horizontal Venting
Horizontally vented heaters must be individually
vented.
Vent pipe must be sloped ¼" (.6 cm) for every 1' (.3
m). For vent lengths greater than 5' (1.5 m),
condensation will form. Insulation is recommended
and condensation drains may be desired. For vents
pitched up toward the vent terminal, place the
condensation drain within 5' (1.5 m) of the heater.
In noncombustible walls only, vent terminal
(P/N 02537801-1P) may be used.
For 4'' (10 cm) vents in either combustible or
noncombustible walls, use vent terminal (P/N
90502100) or equivalent insulated vent terminal.
Follow the manufacturer's instructions for proper
installation.
Instead of an insulated vent terminal, a listed thimble
(with 2" air gap) may be used with a 4" vent cap (P/N
90502102).
8
SECTION 6: VENTING
6.7 Vent Material
Figure 3: Vent and Roof Detail
Vent material may be single wall 26 ga. (minimum)
galvanized steel or equal thickness stainless steel.
6.2.
Vent
Terminal
If penetrating a combustible wall or roof, a listed
thimble with 2" (5 cm) clearance must be used.
Where local codes permit, a single section of type
B-1 vent material may be used at the roof or wall
penetration instead of a thimble. Ensure vent
manufacturer's clearance from vent material is
maintained. Seal annular space of the type B-1 vent
as well as all joints in the remaining vent.
Flashing
or Rain Collar
Roof
Listed Thimble
Vent
2" Air Gap to
Combustible Material
Figure 4: Standard Vented Heater - Vertical and Horizontal Vent Termination
Vent Terminal
Flashing
(By Others)
Listed
Thimble
(2" Clearance)
4" Dia.Vent
Listed
Thimble
90°
Vertical
Option
(2" Clearance)
Bend
Flashing
(By Others)
Horizontal
Option
Vent
Vent
Terminal
12" (31 cm)
Minimum
Condensate
Trap to Drain
(Optional)
Note: Vent supports
not shown.
Model
Vent Diameter
Part Number
UHA 150 - 400
4" (10 cm)
90502102
9
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
Figure 5: Standard Vented Heater - Common Vertical Vent Termination
Type "B" vent cap
(7" or 8") may be used.
(These are not available
from Roberts-Gordon.)
SIDE VIEW
Type "B" Vent Pipe
18" (46 cm)
Min.
Roof
Flashing
Roof
The last section of vent pipe
Approved
Thimble
passing through the roof or
wall may be Type "B" vent pipe.
All other vent materials in the
building must be single wall
vent pipe.
(If Applicable)
Single Wall Pipe
"D"
4" (10 cm)
Single Wall Pipe
4" (10 cm)
Single Wall Pipe
"D" Area must equal sum
of open area of
individual vents.
TOP VIEW
10
SECTION 6: VENTING
Figure 6: Separated Combustion Heater - Vertical and Horizontal Vent Termination
12" (31 cm)
Minimum from air inlet to vent
termination (may be horizontal
or vertical clearance).
Vent
Air Intake*
Vertical
Option
12" (31 cm)
Minimum from air inlet to vent
termination (may be horizontal
or vertical clearance).
Horizontal
Option
90°
Bend
Air Intake
Air Intake
Termination
Vent
Termination
Vent
12" (31 cm)
Minimum from wall
to vent termination.
Condensate
Trap to Drain
(Optional)
Model
UHAS 150 - 400
Model
UHAS 150 - 250
UHAS 300 - 400
Vent Diameter
4" (10 cm)
*Air Intake Diameter
4" (10 cm)
Terminal P/N
90502102
Terminal P/N
90502102
Listed Thimble through
Combustible Wall
5" (13 cm)
90502105
Note: Vent supports not shown
Figure 7: Concentric Vent Box
4" (10 cm) or
5" (13 cm)
Toward
Outside
Seal joint between single wall
and Type B vent with silicone sealant.
6" (15 cm) or 8" (20 cm)
Single Wall Inlet Air Pipe
(By Others)
Concentric
Vent Box
Use 3 sheetmetal
screws equally
spaced around joint.
Toward
Heater
Use 3 sheetmetal
screws equally
spaced around collar.
4" (10 cm) Single
Wall Vent Pipe
(By Others)
11
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
Figure 8: Concentric Vertical and Horizontal Vent Termination - Separated Combustion Heater
Vent Terminal
with Baffle Plate
4" Type B-1
Vent
UHA 150-250:
Storm Collar (By Others)
(Attach with 3 sheet metal screws.)
6" Dia. Single Wall
UHA 300-400:
8" Dia. Single Wall
Combustion
Air Terminal
Flashing
(By Others)
Concentric
Vent Box
6" (16 cm)
Minimum
Air Intake*
12" (31 cm)
Maximum
Vertical
Option
Vent
Condensate Trap
to Drain (Optional)
10' (3 m)
Maximum
Vent Terminal
4"
with Baffle Plate
Type
B-1
Vent
Horizontal
Option
Air Intake*
Concentric
Vent Box
Storm Collar (By Others)
(Attach with 3
sheet metal screws.)
Combustion
Air Terminal
Description
Part Number
UHVK1
Qty.
Concentric Vent Kit (150 - 250)
Concentric Vent Box Top & Side Assembly
Concentric Vent Box Bottom Assembly
Screw #6 x 3/8 Self Drilling
4" Vent Terminal with Baffle Plate
6" Combustion Air Terminal
90504113
90504112
91119100
90502102R
90502103
1
1
14
1
Model
UHAS 150 - 400
Model
UHAS 150 - 250
UHAS 300 - 400
Vent Diameter
4" (10 cm)
*Air Intake Diameter
4" (10 cm)
1
Description
Part Number
UHVK2
Qty.
5" (13 cm)
Concentric Vent Kit (300 - 400)
Concentric Vent Box Top & Side Assembly
Concentric Vent Box Bottom Assembly
Screw #6 x 3/8 Self Drilling
4" Vent Terminal with Baffle Plate
8" Combustion Air Terminal
90504013
90504012
91119100
90502102R
90502104
1
1
14
1
1
12
SECTION 7: AIR SUPPLY
SECTION 7: AIR SUPPLY
7.1 Separated Combustion Installation
When installed as a separated combustion heater,
the air for combustion is drawn in from outside the
building. It is important to ensure that there is
adequate space around heater to provide air for the
axial air distribution fan.
7.2 Unvented Installation
It is important to ensure that there is adequate fresh
air supply at all times for both combustion and
heating requirements in accordance with local and
national codes.
WARNING: Combustion by-products contain a
chemical known to the State of California to cause
cancer and birth defects or other reproductive
harm.
7.3 Building Ventilation
Where ventilation is required, air must be taken from
an outside point where it is not likely to be
contaminated or obstructed.
7.4 Outside Combustion Air Supply
If outside combustion air supply is required,
separated combustion model (UHAS) heaters must
be used.
IMPORTANT: If the building has a slight negative
pressure or corrosive contaminants such as
halogenated hydrocarbons are present in the air, an
outside combustion air supply to the heater is
required. Seal all combustion air pipe joints.
The air supply duct may have to be insulated to
prevent condensation on the outer surface. The
outside air terminal must not be more than 1' (31
cm) above the vent terminal.
7.4.1 Length Requirements
13
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
SECTION 8: GAS PIPING
• Meter and service must be large enough to
handle all the burners being installed plus any
other connected load. The gas pipe which feeds
the system must be large enough to supply the
required gas with a maximum pressure drop of
1/2" w.c. When gas piping is not included in the
layout drawing, contact the local gas supplier.
WARNING
• An isolating valve and union connection should
be used and fitted into the supply adjacent to the
heater.
Fire Hazard
Gas can leak if not installed properly.
• A minimum 1/8" NPT plugged tapping
accessible for test connection must be installed
immediately upstream of the gas supply
connection to the heater.
Failure to follow these instructions can result in death,
injury or porperty damage.
It is important that the gas supply pipe and the
electrical connections do not support any of the
heater’s weight.
A gas meter is connected to the service pipe by the
gas supply company. An existing meter should be
checked, preferably by the company, to ensure that
the meter is adequate for the rate of gas supply
required.
• For suspended heaters, an approved metal
flexible connection between the isolating valve
and the heater may be used. To reduce
pressure loss, use one pipe size larger than
the heater gas connection.
IMPORTANT - The complete installation must be
purged and tested for gas soundness in accordance
with local and national codes.
Installation pipes must be fitted in accordance with
local and national codes. Pipes of smaller size than
the heater inlet gas connection should not be used.
• Do not high pressure (in excess of 1/2 psi
[14" w.c.]) test the gas piping with the burner
connected. Close manual shut-off valve
during any pressure testing equal to or less
than 1/2 psi (14" w.c.). Failure to follow these
instructions can result in property damage.
Check the pipe and tubing ends for leaks before
placing heating equipment into service. When
checking for gas leaks, use a soap and water
solution; never use an open flame.
8.1 Connections
Connect the heater to the gas supply ensuring that
the final connections are as follows:
• Gas supply pipe work is run in medium or heavy
gauge tubing in compliance with local and
national codes.
Figure 9: Gas Connection
• Hold gas nipple
securely with pipe
wrench when
attaching the flex gas
connector.
Option A:
Stainless Steel
Do not bend flexible
Flex Gas
Connector
gas connector
sharply.
• Do not twist flexible
gas connector.
• Ensure all
joints are
gas tight.
Option B:
Medium or Heavy
Gauge Pipe
Gas Shut-off Valve
Gas Connector
Drip Leg
Cap
Union
Connection
14
SECTION 9: WIRING
SECTION 9: WIRING
codes in accordance with: United States: refer to
National Electrical Code® ANSI/NFPA 70 - latest
revision Canada: refer to Canadian Electrical Code
CSA C22.1 Part I - latest revision.
WARNING
9.1 Positioning Thermostats
A room thermostat or ROBERTS GORDON®
control should be mounted on a vibration-free wall or
column at a height of approximately 5' (1.5 m) from
the floor to measure the ambient temperature. It
should be clear of both cold drafts and the direct
path of warm air from the heater.
Avoid mounting thermostat on outside walls or in
areas directly exposed to radiant heat or sunlight.
Install wall tag in a visible location near thermostat.
Electrical Shock Hazard
Disconnect electrical power and gas supply before
servicing.
This appliance must be connected to a properly
grounded electrical source.
Failure to follow these instructions can result in
death or electrical shock.
All heater models require constant 120 V 60 Hz 1Ø
power supply. Check heater(s) rating plate for
electrical rating for proper circuit sizing. For
servicing, a disconnect switch of proper electrical
rating should be installed in the vicinity of the heater.
9.1.1 Fan Control
The heater’s axial fan can be used during the off-
season for air circulation. A low voltage thermostat
with fan control must be used. See Page 15, Section
9.2 for thermostat connection details.
All heaters are equipped with thermostat
connections suitable to power a 24 V thermostat.
Heater must be wired and electrically grounded in
accordance with local codes. In the absence of local
9.2 Low Voltage Thermostat with One Heater
24 Volt
Thermostat
Heating Only
Terminal
Strip
R
G
R
W
C
W
Electrical
Supply
24 Volt
Thermostat
with Fan Control
Terminal
Strip
R
G
R
G
W
C
W
C
Electrical
Supply
15
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
9.3 UHA(S) Series Internal Wiring Diagram
AXIAL FAN
AXIAL FAN (UH 300, 350, 400 ONLY)
BLACK
GREEN
WHITE
L2 L1
WHITE
BLACK
WHITE
GREEN
BLACK
BLOWER
BLACK
WHITE
GREEN
GREEN
GAS VALVE
3
1
BLACK
TRANSFORMER
BLUE
WHITE
GREEN
4
5
YELLOW
YELLOW
BLUE
BROWN
PRESSURE SWITCH
3
1
BLUE
2
5
6
4
ORANGE
ORANGE
R
G
W
C
LIMIT SWITCH
(UH 300, 350,
400 ONLY)
R = 24 VAC TO THERMOSTAT (RED)
G = MANUAL FAN INPUT FROM THERMOSTAT (GREEN)
ORANGE
ORANGE
W= HEAT DEMAND INPUT FROM THERMOSTAT (WHITE)
C = COMMON SIDE OF TRANSFORMER
LIMIT SWITCH
MANUAL RESET LIMIT SWITCH
(UH 30 - 125 ONLY)
IGNITION MODULE
THERMOSTAT INPUT: FIELD SUPPLIED
SENSE
ELECTRODE
BLACK
BLACK
BLACK
BLACK
ACC
CMB BLOWER
BLACK
L1
BLACK
NOTE:
For field wiring into service junction box, or if any of the original wire supplied with the heater
must be replaced, it must be replaced with wiring material having a temperature rating of at least 105°C
and 600 volts. For supply connections use No. 14 AWG or larger wires.
16
SECTION 9: WIRING
9.4 UHA(S) Series Ladder Wiring Diagram
120 VAC
UH 300, 350, 400 Only
CIRCULATION FAN
CIRCULATION FAN
COMBUSTION BLOWER
TRANSFORMER
GAS VALVE
PRESSURE SWITCH
2
5
3
1
FLAME
SENSOR
6
4
FLAME
SPARK
IGNITION
MODULE
LIMIT SWITCH (UH 300, 350, 400 ONLY)
LIMIT SWITCH
ELECTRODE
MANUAL RESET LIMIT SWITCH
(UH 30 - 125 ONLY)
THERMOSTAT CONNECTION
NOTE:
For field wiring into service junction box, or if any of the original wire supplied with the heater
must be replaced, it must be replaced with wiring material having a temperature rating of at least 105°C
and 600 volts. For supply connections use No. 14 AWG or larger wires.
17
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
9.5 Electrical Connection to the Heater
Flexible Conduit
BX Connector
Burner
L1
L2
Ground
Connect wires together
with suitable approved
wire connectors.
Junction Box
Green to Ground
White to L2
Black
White
Green
Black to L1
Note: Junction box is not provided with heater.
Conduit can also be attached directly to heater with wire junction made within the heater cabinet.
18
SECTION 10: OPERATION AND MAINTENANCE
SECTION 10: OPERATION AND MAINTENANCE
Installation, service, and annual inspection of the
heater must be done by a contractor qualified in the
installation and service of gas-fired heating
10.1.2 Electrical Checks
All pre-start-up checks must be carried out before
start-up the heater.
equipment. Read this manual carefully before
installation, operation, or service of this equipment.
All components are accessed via the door secured
by 4 sheet metal screws. Opening the door exposes
live electrical connections and hot components.
1. Check that all site wiring is connected in
accordance with the appropriate wiring diagram
10.1.3 Gas Supply
All aspects of the gas installation including the gas
meter must be inspected, tested for gas tightness
and purged in accordance with local and national
codes.
WARNING
Ensure that the air is fully purged from the heater
inlet pipe up to the main gas valve inlet test nipple.
10.1.4 Mechanical Checks
1. Check that the fan is free to run and
delivery louvers are turned to give required
air deflection.
Electrical Shock Hazard
2. Check that the flue (and air intake for separated
combustion units) is installed in accordance
with these instructions and local regulations.
Use extreme caution during start-up.
Controls compartment contains live electrical
connections.
Failure to follow these instructions can result in
death or electrical shock.
10.2 Begin Start-Up
10.2.1 Before Operating the Heater
To ensure that all the controls are in safe working
order, operate the heater for the first time with the
isolating gas valve turned off and power supply
turned on.
10.1 Pre-Start-Up Checks
All pre-start-up checks must be carried out
before lighting the heater.
Ensure that the heater and all controls are suitable
for the gas, pressure and electrical supply to which
they are to be connected.
1. Turn off the isolating gas valve.
2. Turn up the thermostat above room
temperature. The automatic ignition
sequence will now begin as described
10.1.1 Louvers
Where fitted, the air delivery louvers need to be set
during start-up to give the required air distribution
(optional vertical louvers).
There will be no ignition of the burner and lockout
will occur, which proves the controls are operating
correctly.
WARNING
Cut Hazard
Turn off gas and electrical supply before maintenance.
Fan can start automatically at any time.
Failure to follow these instructions can result in severe
injury or product damage.
19
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
Figure 10: Automatic Burner Control Sequence
Burner Sequence for Ignition Control
START
RUN
SHUT DOWN
Thermostat 24 V
Flue Fan
30 Sec. Purge*
NO
30 Sec. Post Purge
P
Pressure
Switch
C
NC
ts = 10 seconds
Ignition Spark
Start Gas Valve
Flame Signal
Axial Fan
30 Sec. Delay
90 Sec. Delay
*Purge time begins at pressure switch change over.
Required Incoming Signals
If at any stage the flame fails, the control will retry
for ignition. The control has four trials for ignition
before a one hour lockout.
Signals Output By Control
Figure 11: Gas Valve for Models UHA(S) 150 - 400
Top View
Regulator
End View
C
ON
OFF
Outlet
Gas Inlet
Pressure
Description
Part Number
Gas Valve 150 - 225 NG
Gas Valve 150 - 225 LP
Gas Valve 250 - 400 NG
Gas Valve 250 - 400 LP
90032505
90032506
90032520
90032521
Inlet Pressure
20
SECTION 10: OPERATION AND MAINTENANCE
10.2.2 Start-Up the Gas Valve (All Gases)
10.2.2.1 Check Burner Gas Pressure
1. Remove the plug in the outlet (burner) pressure
test point and connect a pressure tap and a
manometer.
10.2.5 External Controls
External controls may include time switch, interlock
switch, room thermostat and frost thermostat.
Operate each control to ensure that they function
correctly. Set the switches (if fitted) and
thermostat(s) to the users’ requirements.
2. With the burner firing, measure the pressure on
the manometer. To adjust the burner pressure,
remove the regulator cover from the valve and
turn the regulator adjustment screw to set the
required burner pressure as stated in the
Technical Data Tables for the correct gas and
10.3 Complete the Start-Up
Ensure that all covers are fitted correctly and all test
points are properly sealed.
10.3.1 Instruction to the User
Explain the controls of the heater to the user
including how to turn it on and off, using the controls
fitted on site.
Give this manual to the user.
Ensure that the user is shown and understands the
importance of maintaining clearances to
combustibles and the user instructions on Page 22,
warnings defined in this manual.
NOTE: If the correct burner pressure cannot be
reached, then check the inlet pressure to the valve
Page 38, Section 15.3 for inlet pressure
requirement.
Do not continue to adjust the regulator if the
pressure is not changing.
If the inlet pressure is too low to allow correct burner
pressure setting, then the gas inlet pressure must be
corrected before completing the commission.
Check Gas Rate
1. After burner pressure adjustment, allow the
heater to operate for at least 15 minutes and
then re-check settings. Adjust pressure setting
if necessary.
2. Check gas flow rate at gas meter.
3. Turn off heater and electrical supply.
4. Remove the manometer and refit all covers to
the valve and tighten the screw of the outlet
pressure tap.
10.2.3 Pressure Switch
The pressure switch is factory pre-set for each
model and is not adjustable.
10.2.4 Turning Off the Heater
Set the thermostat to the "OFF" position or lowest
setting and the main burner will stop.
The fan will run until it is stopped automatically by
the fan thermostat.
Do not use a disconnect switch for control of
heater. Disconnect switch will turn off the fan.
Heat exchanger could be damaged. Warranty will
not cover damage to the heat exchanger if
operated improperly. Only use the disconnect
switch for turning off heater for service or during
off-season.
21
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
SECTION 11: USER INSTRUCTIONS
11.1 User Instructions
11.5 Simple Troubleshooting
The UHA(S) Series heaters are fully automatic and Some possible reasons for the heater not operating
operate from the external controls fitted on site.
are:
1. Gas supply not "ON".
2. Electricity supply not "ON".
WARNING
3. The time and/or temperature controls are not
"ON".
4. A limit switch may have operated. This may be
caused by an interruption of the electrical
supply, failure of the distribution fan or vent or
heat exchanger blockage.
Electrical Shock Hazard
If a temperature limit switch persistently trips, there
is a fault which must be investigated by a contractor
qualified in the installation and service of gas-fired
heating equipment.
Disconnect electrical power before servicing.
Failure to follow these instructions can result in
death or electrical shock.
11.2 Heater Operation
11.5.1 Simple Troubleshooting (Burner Faults)
When the heater has been switched on by the
thermostat installed on site, the main burner will
automatically turn on.
The burner control box will control the safe ignition
of the flame.
All heaters require a constant gas and electricity
supply which must not be interrupted during the
normal operation of this heater.
If the burner fails to ignite for any reason, it will retry
for ignition (4 trials total). After 4 unsuccessful
ignition trials, the control will put the heater into
lockout for 1 hour.
Lockout should not occur during normal operation of
the heater and indicates there is a fault condition
which must be corrected. There is an LED light on
the ignition control that flashes codes to assist in
codes.
11.3 Common User Controls
11.4 Lighting Instructions
Figure 12: LED Diagnostic Codes
11.4.1 To Turn On Heater
LED INDICATION FAULT MODE
1. Ensure that the electrical and gas supplies to
the heater are on. Check that the on site
controls are "ON".
Slow Flash
Fast Flash
2 Flashes
3 Flashes
4 Flashes
Normal Operation - No call for heat.
Normal Operation - Call for heat.
Ignition Lockout - No flame detected.
Airflow Fault - Pressure switch open or closed.
NOTE: The thermostat setting must be above the
ambient temperature for the heater to operate.
Temperature Limit or
Manual Reset Limit Switch Open
5 Flashes
Steady On
Flame Sense Error - Gas valve not energized.
Internal Control Failure
2. The automatic firing sequence will begin as
will now operate automatically under the control
of the on site controls.
11.4.2 To Turn the Heater Off
Set the thermostat to the "OFF" position.
The burner will turn off immediately.
The fan will continue to run for 90 seconds.
To restart, turn the thermostat above room
temperature.
22
SECTION 11: USER INSTRUCTIONS
FOR YOUR SAFETY
If you smell gas:
1. Open windows.
2. DO NOT try to light any appliance.
3. DO NOT use electrical switches.
4. DO NOT use any telephone in
your building.
5. Leave the building.
6. Immediately call your local gas
supplier after leaving the building.
Follow the gas supplier’s
instructions.
7. If you cannot reach your gas
supplier, call the Fire Department.
WARNING
Fire Hazard
Do not store or use petrol or other
flammable vapours and liquids in the
vicinity of this or any other appliance.
Some objects will catch fire or explode
when placed close to heater.
Failure to follow these instructions can
result in death, injury or property
damage.
23
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
SECTION 12: SERVICING
12.1 Servicing Instructions
12.3 Fan/Motor Assembly Maintenance
After start-up, the heater will require maintenance to The main fan bearings are permanently sealed and
be carried out annually. If the heater is used in a
do not need lubrication. Before cleaning, turn off gas
dirty or dusty area, more frequent maintenance may and electrical supply. Remove the fan and use a
be necessary.
small brush or duster to clean the fan blades from
each side. Replace fan when done.
WARNING
12.4 Heat Exchanger Maintenance
The heat exchanger will remain clean unless a
problem has developed with combustion. Inspect the
heat exchanger. Look for signs of overheating at the
front tubes which may indicate burner over firing or
persistently low air flows.
Cut Hazard
12.5 Gas Valve Maintenance
Turn off gas and electrical supply before maintenance.
Fan can start automatically at any time.
No regular maintenance is required on this device.
Do not repair or disassemble gas valve.
Replace faulty gas valves with genuine
ROBERTS GORDON® replacement parts.
Failure to follow these instructions can result in severe
injury or product damage.
NOTE 1: After any maintenance or repair work,
always test fire the heater in accordance with the
are in working order before leaving the heater to
operate. Minor faults may be traced by using the
12.6 Combustion Fan
The combustion fan should not require
maintenance. However, if the air pressure switch is
causing burner lockout, then remove the combustion
fan from the vent box by unscrewing the three
screws at the mounting plate. Remove the four
screws attaching the mounting plate to the fan inlet
free to run and that the fan wheel is clean.
NOTE 2: Check all gas pipes and pipe joints to
ensure there are no cracks or gas leaks. Any cracks
in the pipes or pipe joints must be repaired.
12.7 Venting and Air Intake Pipe
Inspect all venting and air intake pipe. Ensure that
all seams are sealed and suspension points secure.
Repair suspension points if any part of the venting
or combustion air pipe is sagging. Check to make
sure any insulation is not missing or in poor
condition. Replace as necessary. Check all venting
and air intake components to ensure they are in
good condition, gas tight and corrosion-free.
NOTE 3: Inspect all suspended components and
hardware. Ensure that they are in good condition,
properly tightened, and corrosion free.
12.2 Burner Maintenance
1. Open the door and remove the burner compart-
2. Clean any deposits from the main burner which
may have formed in the injectors or venturi of
3. Remove the ignition electrode and flame probe.
Check condition of ignition electrode and flame
probe. Clean off any deposits which may have
been formed, check condition of ceramic
insulators. Replace as necessary.
24
SECTION 12: SERVICING
12.8 Maintenance Checklist
Installation Code and Annual Inspections: All
installations and service of ROBERTS GORDON®
equipment must be performed by a contractor
qualified in the installation and service equipment
sold and supplied by Roberts-Gordon and conform
to all requirements set forth in the ROBERTS
GORDON® manuals and all applicable
WARNING
governmental authorities pertaining to the
installation, service and operation of the equipment.
Explosion Hazard
Service and annual inspection must be done by a
contractor qualified in the installation and service of
gas-fired heating equipment or your gas supplier.
To help facilitate optimum performance and safety,
Roberts-Gordon recommends that a qualified
contractor annually inspect your ROBERTS
GORDON® equipment and perform service where
necessary, using only replacement parts sold and
Turn off gas and electrical supplies before performing
service or maintenance.
Failure to follow these instructions can result in death, supplied by Roberts-Gordon.
injury or property damage.
The Vicinity of the Heater Do not store or use flammable objects, liquids or vapors near the heater.
Immediately remove these items if they are present.
Vehicles and Other
Objects
Maintain the clearances to combustibles.
Do not hang anything from, or place anything on, the heater.
Make sure nothing is lodged in between the heat exchanger or in the louvers.
Immediately remove objects in violation of the clearances to combustibles.
Vent Pipe/Terminals
Venting must be intact. Using a flashlight, look for obstructions, cracks on the
pipe, gaps in the sealed areas or corrosion.
The area must be free of dirt and dust.
Remove any carbon deposits or scale using a wire brush.
If the vent terminal has a screen built in, remove any dirt, dust or deposits
from the screen.
Combustion Air Intake
Pipe
Intake pipe and inlet must be intact. Look for obstructions, cracks on the pipe,
gaps in the sealed areas or corrosion.
The area must be free of dirt and dust. Clean and reinstall as required.
Heat Exchanger
Make sure there are no cracks.
Make sure there is no sagging, bending or distortion.
Clean or replace as required.
Gas Line and Shut-off
Valves
25
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
Burner Observation
Window
Make sure it is clean and free of cracks or holes.
Clean and replace as required.
Combustion Fan Scroll,
Wheel and Motor
Compressed air or a vacuum cleaner may be used to clean dust and dirt.
Inshot Burners and
Orifices
Clear of obstructions (even spider webs will cause problems).
Carefully remove any dust and debris from the burner.
Direct-Spark Igniter
Replace if there are cracked ceramics, excessive carbon residue, or erosion
of the electrode.
The electrode gap should be 1/8" (3.2 mm).
Thermostat
There should be no exposed wire or damage to the device or wiring.
Suspension Points
Make sure the heater is hanging securely.
Look for signs of wear on the suspension materials or ceiling.
Silicone Tubing
Gas Valve
Ensure tight, secure fit on all pressure fittings at pressure switch,
burner partition, and blower outlet.
Verify that cap covering pressure regulator adjustment screw is secure and
has not been tampered with.
Verify all wiring connections.
Condensate Drain
(when installed)
Flush drain and clear any obstructions.
26
SECTION 13: TROUBLESHOOTING
SECTION 13: TROUBLESHOOTING
13.1 General
WARNING
Explosion Hazard
Installation must be done by a registered installer/
contractor qualified in the installation and service of
gas-fired heating equipment or your gas supplier.
Failure to follow these instructions can result in death,
injury or property damage.
Start
Are gas & electrical
supplies on?
No
Turn on supplies.
Yes
Wait 10-15 minutes for limit
switch to cool. Does fan
stop running?
Does axial fan run
immediately upon supplying
power to heater?
Fan and limit switch are
operating normally.
Yes
Yes
No
Replace temperature
limit switch.
No
Burner has locked out due
to ignition failure. Use
Troubleshooting for Automatic
Ignition Burner Systems
section to test burner.
Is ignition control showing a
"2 flashes" led code?
Yes
No
No
Use Troubleshooting for
Combustion Fan section to
test fan.
Does the combustion
fan run?
Yes
With external controls (i.e.
thermostat) on, does the
burner continue through the
heating cycle?
The limit switch has
tripped. See Manual Reset
Limit Switch Figure.
Has burner “Locked Out”?
Yes
No
No
Replace limit switch.
No
Yes
Use Troubleshooting for
Automatic Ignition Burner
Systems section to test burner.
Ensure proper air flow
clearance for axial fan.
Open louvers slightly.
Replace axial fan if it does
not operate.
Yes
If problems persist, contact
Roberts-Gordon, LLC at
Heater Operating
TROUBLESHOOT ENDS.
No
27
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
13.2 Troubleshooting For Automatic Ignition Burner Systems
WARNING
Start
Are gas & electrical
Turn on supplies.
Turn on controls.
No
No
supplies on?
Yes
Electrical Shock Hazard
Are external controls
(i.e. Thermostat) on?
Do not touch ignition components.
Voltage from ignition components is high.
Yes
Failure to follow these instructions can
Press in reset button on
manual reset limit switch
result in death or electrical shock.
Is ignition control showing
a "4 flashes" led code?
Yes
No
No
Is 120 V supply at fan
connections?
Does flue fan run?
Yes
Flue fan faulty; replace
No
Burner control faulty or wiring
connections faulty. Repair
or replace as necessary
Yes
Check for too much vent/air inlet duct. Check for blockage in
vent and combustion air circuit. Check for faulty air pressure
switch. Check pressure switch hoses for leaks or cracks.
Do not attempt to circumvent pressure switch circuit to
place unit in operation.See Pressure Switch section for details.
Does air pressure switch
change over?
No
Yes
Is ignition lead okay and
connected?
Ignition control faulty;
replace.
Wait 30 - 40 seconds.
No
No
Yes
Yes
No
Does ignition spark operate?
Is spark electrode okay?
See Ignition Control section.
Yes
Is the gas valve operating?
To test valve, See
Troubleshooting for Gas
Valves section.
Replace valve.
Does the flame light?
Yes
Trace fault in supervision
system. See
Troubleshooting
for Flame Supervision
System section.
Is the flame current at
least 1 µAmp DC when
the flame ignites?
Is ignition control showing
a "2 flashes" led code?
Yes
No
If problems persist, contact
Roberts-Gordon, LLC at
Heater Operating
TROUBLESHOOT ENDS.
No
For your safety and optimum heater performance,
use only ROBERTS GORDON® replacement parts.
Conduct start-up procedure as shown on Page
28
SECTION 13: TROUBLESHOOTING
13.3 Troubleshooting for Flame Supervision System
To measure flame current, connect a 0 - 50 μA DC meter in
series with the flame probe. If the meter reads negative
values, then reverse the test leads.
START
Connect a DC ammeter in
series with the flame probe.
Use General
Troubleshooting section to
trace the fault.
Is the flame present and
at least 1 µA DC flame
current?
No
Yes
Yes
Yes
Is the connecting lead
damaged? Is the flame probe
damaged or touching earthed
components?
Is there a current flowing in the
flame probe circuit with no
flame present?
Repair or replace as
necessary.
Yes
No
Is inlet burner gas pressure
correct? Is live and neutral
polarity correct? Is
Does “lockout” occur when
there is a flame present?
Yes Replace ignition control.
flame probe circuit correct?
No
Repair or replace as
necessary.
No
If problems persist, contact
Roberts-Gordon, LLC at
Heater Operating
TROUBLESHOOT ENDS.
No
NOTE: Minimum flame probe current 1 μA DC. Typical flame probe current 3-5 μA DC.
29
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
13.4 Troubleshooting for Gas Valves
START
Is gas pressure at inlet of the
valve correct for gas type?
Note pressure found.
Fault elsewhere.
No
No
Correct pressure problem.
Yes
Valve or ignition control
faulty. Replace with
one of correct type.
Does gas pressure at outlet
of the valve rise when
valve turns on?
Yes
Does gas pressure at
outlet of valve return to zero or
lower when valve turns off?
Valve faulty.
Replace with one of
correct type.
No
No
Yes
If problems persist, contact
Roberts-Gordon, LLC at
Valve Operating
TROUBLESHOOT ENDS.
13.5 Troubleshooting for Combustion Fan
START
Does combustion fan run
automatically when there
is a call for heat?
Correct power
supply problem.
No
Yes
Fan motor faulty.
Replace with correct type.
Yes
Does fan turn on and
off while burner is firing
continously?
Check fan motor leads for
loose connections.
Yes
No
If problems persist, contact
Roberts-Gordon, LLC at
Fan Operating
TROUBLESHOOT ENDS.
No
For your safety and optimum heater performance,
use only genuine ROBERTS GORDON® replacement parts.
30
SECTION 14: REPLACEMENT PARTS
SECTION 14: REPLACEMENT PARTS
See warnings and notes on Page 24, Section 12
before removing or replacing parts.
Burner Components
All serviceable burner parts are accessed by the
door on the side of the heater. Remove the
sheetmetal screws.
14.1 Gas Valve
Remove the gas supply pipe at the heater inlet.
C
ON
OFF
Description
Part Number
Gas Valve, NG (Models UHA[S] 150 - 225)
Gas Valve, LP (Models UHA[S] 150 - 225)
Gas Valve, NG (Models UHA[S] 250 - 400)
Gas Valve, LP (Models UHA[S] 250 - 400)
90032505
90032506
90032520
90032521
remove gas valve/manifold.
Replace in reverse order. Verify that the gas flow
direction of the valve is correct. Use a minimum
amount of gas seal on the thread joint. Check that
all the joints are leak free. Reset gas valve. See
IT IS IMPORTANT THAT ONLY THE CORRECT
GAS VALVE IS USED WHEN REPLACING THESE
CONTROLS.
31
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
14.2 Burner Compartment
The burner compartment is
a sealed compartment.
Following any work,
Burner
compartment
cover
re-seal the compartment
with the gas pipe rubber
seal fully in place and all
screws fitted and tight.
Flame probe
Viewing port
for flame probe
Remove flexible
air duct from spigot
Ignition electrode
Viewing port
for ignition electrode
Remove
access plate
Rubber Seal
Remove screws and
pull off burner cover
14.2.1 Burner Injectors
Ensure gas tight fitting of injectors.
Ensure correct alignment with burners.
Ensure all pipe joints are gas tight.
Manifold
Burners
Injectors
Remove manifold
screws and pull
out manifold
Manifold
Unscrew
Injectors
Burner
Screws
Marking
Folded
Hem
UHA[S]
150
UHA[S]
175
UHA[S]
200
UHA[S]
225
UHA[S]
250
UHA[S]
300
UHA[S]
350
UHA[S]
400
Orifice Quantity
Natural Gas (G20)
Orifice Marking
7
8
9
10
11
12
14
14
43
43
2.25 mm
2.25 mm
2.25 mm
40
40
40
RG P/N
91930043
91930043
91930225
91930225
91930225
91930040
91930040
91930040
Propane (G31)
Orifice Marking
RG P/N
1.35 mm
1. 35 mm
54
54
54
1.45 mm
53
53
91930135
91930135
91930054
91930054
91930054
91930145
91930053
91930053
32
SECTION 14: REPLACEMENT PARTS
14.3 Ignition Electrode and Flame Probe
Burners
Limit
Thermostat
Flame
Probe
Flame
Probe
Remove all
burner compartment
screws to remove
the burner
Remove
Screw
compartment and
access the
"Front View".
Burner Compartment
Front Views
Ignition
Electrode
Ignition
Electrode
.120
(3 mm)
spark
gap
Burners
To replace the electrode or flame probe, remove the electrical lead and screw.
Pull out from mounting. Refit in reverse ensuring that the gap to burner is as shown in the
front view of the burner compartment.
Description
Spark Electrode
Part Number
90427411
90439300
92000001
92000002
90412103
90412105
Qty.
1
1
1
1
Automatic Ignition Flame Probe
Inshot Burners (150, 175)
Inshot Burners (200 - 400)
Limit Switch (150 - 400)
Limit Switch (300 - 400)
1
2
33
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
14.4 Combustion Fan Vertical Installation
Remove screws securing outlet
flange to the flue adapter.
Rear Panel
Flue Adapter
to Flue Fan
screws
Hole
Refit in reverse order.
Vent Box
Flue
Adapter
Vent Box
Screws
Outlet
Gasket
Flue Fan
Disconnect
electrical connections
at plug in tabs.
Remove screws securing flue
fan mounting plate to vent box.
Remove screws securing
mounting plate to fan.
Vent Box
Mounting
Plate
Refit in reverse.
Mounting Plate
to Vent Box
Screws
Use new gaskets.
Ensure sealed joints.
Ensure mounting plate orifice is
clear and not obstructed.
Gasket
Gasket
Mounting Plate
to Flue Fan
Screws
Air Plate
UHA[S]
150 - 175
UHA[S]
200 - 300
UHA[S]
350 - 400
Exhaust Fan P/N
90710405
90710403
90710402
IT IS IMPORTANT THAT ONLY THE CORRECT COMBUSTION FAN SPECIFIED FOR EACH MODEL
TYPE IS USED WHEN REPLACING THESE ITEMS.
34
SECTION 14: REPLACEMENT PARTS
14.5 Pressure Switch
Pull off 3 way connector. Spring open plastic clips of
mounting cradle. Replace with correct type of
pressure switch for model. The pressure switches
are color coded for each pressure setting.
WARNING
Carbon Monoxide Hazard
Use correct pressure switch specified for each model.
Use of incorrect pressure switch or disabling
pressure switch circuit could cause unsafe condition.
Failure to follow these instructions can result in
death or serious injury.
Carry out a commission after working on or
changing a pressure switch. See Page 19, Section
UHA[S]
UHA[S]
UHA[S]
250
UHA[S]
UHA[S]
400
P/N
150 - 175
200 - 225
300 - 350
90439802
yellow
.32
90439808
orange
.79
90439803
gray
90439807
brown
.68
90439808
orange
.79
Color Code
Set Point in. w.c.
.41
35
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
14.6 Ignition Control
14.8 Limit Switches
The control mounts to the electrical plate. Pull out
ignition cable and wiring from board, noting their
positions.
Release the four mounting standoffs.
Refit in reverse. Ensure correct location of ignition
cable and all other wiring.
14.8.1 Removal and Replacement
1. Remove the electrical connections to the
switch.
2. Unscrew the two screws securing the
switch.
3. Fit a new switch with two screws.
14.7 Axial Fan/Guard/Motor Assembly
The axial fan unit for the heater is supplied
completely assembled and balanced.
4. Reconnect the electrical connections and test
operation.
14.7.1 Fan Removal and Replacement
Remove the mounting hardware.
Description
Part Number
Qty.
1
1
Axial Fan UHA[S] 150 - 175
Axial Fan UHA[S] 200 - 250
Axial Fan UHA[S] 300 - 400
90710416
90710417
90710416
2
14.7.2 To Replace the Fan Assembly
To replace the fan assembly, reverse the procedure
shown above.
• Check that the fan blades are free to rotate
before turning on the power to the fan.
• Strictly comply with the color code of the fan
wires to ensure correct operation. See Page 16,
Section 9.3 wiring diagram.
• Use only genuine ROBERTS GORDON®
replacement parts.
36
SECTION 15: SPECIFICATIONS
SECTION 15: SPECIFICATIONS
15.1 Standard (Models 150 - 400) UHA(S) Series Dimension Data
Top View
Heater must be supported
at these points from above
or below.
C
E
D
77
Support
Centers
4 x 3/8" Captive Nuts Provided
19 3/8"
(49 cm)
End View
25 1/2" (65 cm)
I
Z
Rear View
Air Intake
(UHAS only)
F
G
B
H
Flue
Lockout Reset
Electrical
Cable Entry
Gas
Supply
6 1/2"
(17 cm)
A
UHA[S] UHA[S]] UHA[S]
UHA[S]
225
UHA[S]
250
UHA[S]
300
UHA[S]
350
UHA[S]
400
Model
150
175
200
in
(cm)
in
(cm)
in
(cm)
in
(cm)
in
(cm)
in
(cm)
42.4
(108)
26.9
(68)
17.7
(45)
12.3
(31)
12.4
(32)
15.5
(39)
42.4
(108)
26.9
(68)
17.7
(45)
12.3
(31)
12.4
(32)
15.5
(39)
42.4
(108)
35.2
(89)
17.7
(45)
12.3
(31)
12.4
(32)
17.5
(44)
42.4
(108)
35.2
(89)
17.7
(45)
12.3
(31)
12.4
(32)
17.5
(44)
42.4
(108)
35.2
(89)
17.7
(45)
12.3
(31)
12.4
(32)
17.5
(44)
52.3
(133)
43.5
(110)
24.7
(63)
12.3
(31)
15.3
(39)
13.8
(35)
52.3
(133)
43.5
(110)
24.7
(63)
12.3
(31)
15.3
(39)
13.8
(35)
52.3
(133)
43.5
(110)
24.7
(63)
12.3
(31)
15.3
(39)
13.8
(35)
A
B
C
D
E
F
G
H
I
Width
Height
Support Spacing
Support Spacing
Support Spacing
Centre of Flue
Centre of
Flue/Air Intake
in
(cm)
5.5
(14)
5.5
(14)
6.4
(16)
6.4
(16)
6.4
(16)
7
(18)
7
(18)
7
(18)
in
(cm)
in
(cm)
in
(cm)
8.2
(21)
5.8
(15)
34
(86)
8.2
(21)
5.8
(15)
34
(86)
8.8
(22)
5.8
(15)
34
(86)
8.8
(22)
5.8
(15)
34
(86)
8.8
(22)
5.8
(15)
34
(86)
11
(28)
5.8
(15)
34
(86)
11
(28)
5.8
(15)
34
(86)
11
(28)
5.8
(15)
34
(86)
Position of Flue
Gas Inlet Position
Length
Z
37
COMBAT® UHA UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
15.2 General Technical Data Table (All Models)
UHA[S] UHA[S] UHA[S] UHA[S] UHA[S] UHA[S] UHA[S] UHA[S]
150
175
200
10.6
3716
225
10.6
3716
250
10.6
3716
300
350
400
Full Load Amps @ 115 V
Air Volume
A
5.8
5.8
11.6
11.6
11.6
CFM
2245
2245
4663
4663
4663
Flue and AIr Intake
Flue Intake Size
Air Intake Size
in (cm) 4 (10)
in (cm) 4 (10)
4 (10)
4 (10)
40 (1)
4 (10)
4 (10)
40 (1)
4 (10)
4 (10)
40 (1)
4 (10)
4 (10)
40 (1)
4 (10)
5 (13)
40 (1)
4 (10)
5 (13)
40 (1)
4 (10)
5 (13)
40 (1)
*Maximum Straight Flue/Air Intake ft (m)
40 (1)
*Do not exceed the maximum length of flue stated or heater may not operate properly.
15.3 Technical Data Table (All Models)
UHA[S] UHA[S] UHA[S] UHA[S] UHA[S] UHA[S] UHA[S] UHA[S]
150
150
123
82
175
200
200
164
82
225
225
184.5
82
250
250
205
82
300
300
246
82
350
350
287
82
400
385
315.7
82
Total Input
Total Output
Efficiency
(Btu/h) x (1000)
(Btu/h) x (1000)
%
175
143.5
82
Natural Gas (G20) Data - Inlet Pressure 5.0 in w.c. Min., 14 in w.c. Max.
Burner Pressure in. w.c. 3.2 3.4 3.7
3.7
4.0
2.7
9.4
2.5
9.3
3.3
LPG / Propane (G31) Data - Inlet Pressure Inlet Pressure 12.0 in w.c. Min., 14 in w.c. Max.
Burner Pressure in. w.c. 9.9 10.4 10.5 10.7 10.7
11.1
38
SECTION 16: THE ROBERTS GORDON® COMBAT® UHA-SE-
SECTION 16: THE ROBERTS GORDON®
COMBAT® UHA-SERIES WARRANTY
ROBERTS-GORDON WILL PAY FOR:
Within 24 months from date of purchase by buyer or 27
months from date of shipment by Roberts-Gordon
(whichever comes first), replacement parts will be
provided free of charge for any part of the product which
fails due to a manufacturing or material defect.
The data plate and/or serial number are removed,
defaced, modified or altered in any way.
The ownership of the ROBERTS GORDON® COMBAT®
UHA-Series is moved or transferred. This warranty is
nontransferable.
Roberts-Gordon is not permitted to inspect the damaged
controller and/or component parts.
READ YOUR INSTALLATION, OPERATION AND
SERVICE MANUAL
If you have questions about your controller, contact your
installing professional. Should you need Replacement
Parts or have additional questions, call or write Roberts-
Gordon:
U.S.A.
1250 William Street
P. O. B ox 4 4
Roberts-Gordon will require the part in question to be
returned to the factory. Roberts-Gordon will, at its sole
discretion, repair or replace after determining the nature
of the defect and disposition of part in question.
ROBERTS GORDON® Replacement Parts are warranted
for a period of 18 months from date of shipment from
Roberts-Gordon or the remaining ROBERTS GORDON®
COMBAT® UHA-Series warranty.
Buffalo, New York 14240-0044
716.852.4400
On the web at: www.rg-inc.com
ROBERTS-GORDON WILL NOT PAY FOR:
Service trips, service calls and labor charges.
Shipment of replacement parts.
Roberts-Gordon's liability, and your exclusive
remedy, under this warranty or any implied warranty
(including the implied warranties of merchantability
and fitness for a particular purpose) is limited to
providing replacement parts during the term of this
warranty. Some jurisdictions do not allow limitations on
how long an implied warranty lasts, so this limitation may
not apply to you. There are no rights, warranties or
conditions, expressed or implied, statutory or otherwise,
other than those contained in this warranty.
Claims where the total price of the goods have not
been paid.
Damage due to:
• Improper installation, operation or maintenance.
• Misuse, abuse, neglect, or modification of the
ROBERTS GORDON® COMBAT® UHA-Series in any
way.
• Use of the ROBERTS GORDON® COMBAT® UHA-
Series for other than its intended purpose.
Roberts-Gordon shall in no event be responsible for
incidental or consequential damages or incur liability
for damages in excess of the amount paid by you for
the ROBERTS GORDON® COMBAT® UHA-Series.
Some jurisdictions do not allow the exclusion or limitation
of incidental or consequential damages, so this limitation
or exclusion may not apply to you. This warranty gives
you specific legal rights, and you may also have other
rights which vary from jurisdiction to jurisdiction.
• Incorrect gas or electrical supply, accident, fire, floods,
acts of God, war, terrorism, or other casualty.
• Improper service, use of replacement parts or
accessories not specified by Roberts-Gordon.
• Failure to install or maintain the ROBERTS
GORDON® COMBAT® UHA-Series as directed in the
Installation, Operation and Service manual.
• Relocation of the ROBERTS GORDON® COMBAT®
UHA-Series after initial installation
• The use of the ROBERTS GORDON® COMBAT®
UHA-Series in a corrosive atmosphere containing
contaminants.
• The use of the ROBERTS GORDON® COMBAT®
UHA-Series in the vicinity of a combustible or
explosive material.
• Any defect in the ROBERTS GORDON® COMBAT®
UHA-Series arising from a drawing, design, or
specification supplied by or on behalf of the
consumer.
• Damage incurred during shipment. Claim must be
filed with carrier.
Roberts-Gordon shall not be responsible for failure to
perform under the terms of this warranty if caused by
circumstances out of its control, including but not limited
to war, fire, flood, strike, government or court orders, acts
of God, terrorism, unavailability of supplies, parts or
power. No person is authorized to assume for Roberts-
Gordon any other warranty, obligation or liability.
LIMITATIONS ON AUTHORITY OF
REPRESENTATIVES:
No representative of Roberts-Gordon, other than an
Executive Officer, has authority to change or extend these
provisions. Changes or extensions shall be binding only if
confirmed in writing by Roberts-Gordon's duly authorized
Executive Officer.
WARRANTY IS VOID IF:
The ROBERTS GORDON® COMBAT® UHA-Series is not
installed by an electrician qualified in the installation and
service of control systems for heating equipment.
You cannot prove original purchase date and required
annual maintenance history.
39
Attach this information to the wall near the ROBERTS GORDON® heater
®
Read the Installation, Operation and Service Manual thoroughly before installation, operation or service.
OPERATING INSTRUCTIONS
WARNING
1. STOP! Read all safety instructions on this information sheet.
2. Open the manual gas valve in the heater supply line.
3. Turn on electric power to the heater.
4. Set the thermostat to desired setting (above ambient temperature).
The automatic starting sequence begins.
TO TURN OFF THE HEATER
1. Turn the thermostat/time switch to 'OFF' or lowest setting. The burner
will turn 'OFF' immediately, but fans will continue to cool heat exchanger
until the fan thermostat switches off.
Fire Hazard
Some objects can catch fire or explode when placed
IF THE HEATER WILL NOT OPERATE, TO ENSURE YOUR SAFETY,
close to heater.
FOLLOW THESE INSTRUCTIONS TO SHUT DOWN YOUR HEATER
Keep all flammable objects, liquids and vapors the
required clearances to combustibles away from heater.
1. Set the thermostat to off or the lowest setting.
2. Turn off electric power to the heater.
3. Turn off the manual gas valve in the heater supply line.
Failure to follow these instructions can result in death,
injury or property damage.
4. Call your installer/contractor qualified in the installation and service
of gas-fired heating equipment.
Installation Clearances
Clearances to Combustibles
Roof Terminal
Top
Top
(Optional separated
combustion concentric
venting shown.)
Left
Left
Right
Right
Top*
10'
(3 m)
Bottom
Bottom
Wall
Terminal
Rear*
Max. Mounting Height*
Models 30 - 125
Models 150 - 400
150 - 400
6" (15 cm)
3" (8 cm)
31" (79 cm)*
6" (15 cm)
2" (5 cm)
30 - 125
1" (2.5 cm)
0" (0 cm)
1" (2.5 cm)
18" (46 cm)*
2" (5 cm)
Models
Top
Bottom
Right
Left
30 - 125
1" (2.5 cm)
18" (46 cm)
*Models
Top
150 - 400
6" (15 cm)
24" (61 cm)
Rear
Max Mounting Height1
12' (3.7 m) - 20' (6 m)
20' (6 m) - 30' (9 m)
1Heaters can be mounted higher if destratification fans are installed. See Installation, Operation
and Service Manual for specific mounting height recommendations.
NOTE: Venting directly from top of heater not applicable on Models 150-400.
Vent
* Clearance needed for servicing.
Roberts-Gordon, LLC
Telephone: 716.852.4400
Fax: 716.852.0854
Toll Free: 800.828.7450
1250 William Street
P.O. Box 44
Buffalo, NY 14240-0044 USA
Installation Code and Annual Inspections:
All installations and service of ROBERTS GORDON® equipment must be performed by a contractor qualified in the installation and service of equipment sold and supplied by Roberts-Gordon and
conform to all requirements set forth in the ROBERTS GORDON® manuals and all applicable governmental authorities pertaining to the installation, service and operation of the equipment. To help
facilitate optimum performance and safety, Roberts-Gordon recommends that a qualified contractor annually inspect your ROBERTS GORDON® equipment and perform service where necessary,
using only replacement parts sold and supplied by Roberts-Gordon.
For installations at elevations above 2000' (610 m), the appliance shall be derated 4% for each 1000' (305 m) of elevation above sea level.
Further Information:Applications, engineering and detailed guidance on systems design, installation and equipment performance is available through ROBERTS GORDON® representatives. Please
contact us for any further information you may require, including the Installation, Operation and Service Manual.
Models 100-400 are not for residential use.
© 2007 Roberts-Gordon, LLC
Printed in U.S.A.
P/N 91040031 Rev B
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