Roberts Gorden Uha Series 200 User Manual

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  
13.2 Troubleshooting For Automatic Ignition Burner  
Systems...................................................................28  
15.1 Standard (Models 150 - 400) UHA(S) Series  
Dimension Data .........................................................37  
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  
connected to the vent. See Page 7, Section 6.  
• Must be installed in a level position with  
horizontal discharge.  
• May be mounted on a shelf of non-combustible  
material.  
• May be suspended from above (See Page 6,  
Figure 2) or from wall brackets of sufficient  
strength to support the heater as listed in the  
Dimension Data Table on Page 37, Section 15.1.  
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.  
For typical suspension, See Page 6, Figure 2.  
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).  
For vent termination See Page 9, Figure 3 through  
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  
terminals. See Page 12, Figure 8. As an option, the  
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.  
Completely seal all joints, refer to Page 7, Section  
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  
Follow the constraints listed on Page 8, Section 6.6.  
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  
Connect gas supply according to Figure 9.  
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  
with the burner firing. See Technical Data Tables on  
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  
fault correction. See Figure 12 for LED indication  
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  
described on Page 20, Figure 10. The heater  
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.  
To change gas control valves, See Page 31, Step  
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  
start-up instructions on Page 19, Section 10 through  
Page 21, Section 10.3.1 to ensure all safety systems  
are in working order before leaving the heater to  
operate. Minor faults may be traced by using the  
troubleshooting charts on Page 27, Section 13  
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  
(See Page 34, Section 14.4). Ensure that the fan is  
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  
Check for gas leaks. See Page 14, Section 8.  
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.  
Conduct start-up procedure as shown on Page 19, Section 10.  
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  
Follow steps in Section 14.2 and Section 14.2.1 to  
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.  
Carry out a start-up after working on or changing a combustion fan. See Page 22, Section 11.  
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  
10.  
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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