Trane Gas Unit Heaters Installation And Maintenance Manual GMND SVX01B EN 03/16/2012 Installation, Operation, Heater Separated Combustion Indoor Fired Duc

2015-04-02

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Installation, Operation,
and Maintenance

Gas Unit Heater
Separated Combustion Indoor Gas-Fired Duct Furnace

SAFETY WARNING
Only qualified personnel should install and service the equipment. The installation, starting up, and
servicing of heating, ventilating, and air-conditioning equipment can be hazardous and requires specific
knowledge and training. Improperly installed, adjusted or altered equipment by an unqualified person could
result in death or serious injury. When working on the equipment, observe all precautions in the literature
and on the tags, stickers, and labels that are attached to the equipment.

March 2012

GMND-SVX01B-EN

Warnings, Cautions and Notices
Warnings, Cautions and Notices. Note that warnings,
cautions and notices appear at appropriate intervals
throughout this manual. Warnings are provide to alert
installing contractors to potential hazards that could result
in death or personal injury. Cautions are designed to alert
personnel to hazardous situations that could result in
personal injury, while notices indicate a situation that
could result in equipment or property-damage-only
accidents.
Your personal safety and the proper operation of this
machine depend upon the strict observance of these
precautions.
Read this manual thoroughly before operating or servicing
this unit.
ATTENTION: Warnings, Cautions and Notices appear at

appropriate sections throughout this literature. Read
these carefully:
Indicates a potentially hazardous
situation which, if not avoided, could
result in death or serious injury.
Indicates a potentially hazardous
CAUTIONs situation which, if not avoided, could
result in minor or moderate injury. It
could also be used to alert against
unsafe practices.
a situation that could result in
NOTICE: Indicates
equipment or property-damage only

WARNING

Important
Environmental Concerns!
Scientific research has shown that certain man-made
chemicals can affect the earth’s naturally occurring
stratospheric ozone layer when released to the
atmosphere. In particular, several of the identified
chemicals that may affect the ozone layer are refrigerants
that contain Chlorine, Fluorine and Carbon (CFCs) and
those containing Hydrogen, Chlorine, Fluorine and
Carbon (HCFCs). Not all refrigerants containing these
compounds have the same potential impact to the
environment. Trane advocates the responsible handling of
all refrigerants-including industry replacements for CFCs
such as HCFCs and HFCs.

Responsible Refrigerant Practices!
Trane believes that responsible refrigerant practices are
important to the environment, our customers, and the air
conditioning industry. All technicians who handle
refrigerants must be certified. The Federal Clean Air Act
(Section 608) sets forth the requirements for handling,
reclaiming, recovering and recycling of certain
refrigerants and the equipment that is used in these
service procedures. In addition, some states or
municipalities may have additional requirements that

must also be adhered to for responsible management of
refrigerants. Know the applicable laws and follow them.

WARNING
Proper Field Wiring and Grounding
Required!
All field wiring MUST be performed by qualified
personnel. Improperly installed and grounded field
wiring poses FIRE and ELECTROCUTION hazards. To
avoid these hazards, you MUST follow requirements for
field wiring installation and grounding as described in
NEC and your local/state electrical codes. Failure to
follow code could result in death or serious injury.

WARNING
Personal Protective Equipment (PPE)
Required!
Installing/servicing this unit could result in exposure to
electrical, mechanical and chemical hazards.
•

Before installing/servicing this unit, technicians
MUST put on all Personal Protective Equipment (PPE)
recommended for the work being undertaken.
ALWAYS refer to appropriate MSDS sheets and OSHA
guidelines for proper PPE.

•

When working with or around hazardous chemicals,
ALWAYS refer to the appropriate MSDS sheets and
OSHA guidelines for information on allowable
personal exposure levels, proper respiratory
protection and handling recommendations.

•

If there is a risk of arc or flash, technicians MUST put
on all Personal Protective Equipment (PPE) in
accordance with NFPA 70E or other country-specific
requirements for arc flash protection, PRIOR to
servicing the unit.

Failure to follow recommendations could result in death
or serious injury.
ATTENTION: READ THIS MANUAL AND ALL LABELS
ATTACHED TO THE UNIT CAREFULLY BEFORE
ATTEMPTING TO INSTALL, OPERATE OR SERVICE THESE
UNITS! CHECK UNIT DATA PLATE FOR TYPE OF GAS AND
ELECTRICAL SPECIFICATIONS AND MAKE CERTAIN THAT
THESE AGREE WITH THOSE AT POINT OF INSTALLATION.
RECORD THE UNIT MODEL AND SERIAL No.(s) IN THE
SPACE PROVIDED. RETAIN FOR FUTURE REFERENCE.

GMND-SVX01B-EN

Warnings, Cautions and Notices

WARNING
Hazardous Service Procedures!
The maintenance and troubleshooting procedures
recommended in this manual could result in exposure
to electrical, mechanical or other potential safety
hazards. Always refer to the safety warnings provided
throughout this manual concerning these procedures.
When possible, disconnect all electrical power
including remote disconnect and discharge all energy
storing devices such as capacitors before servicing.
Follow proper lockout/tagout procedures to ensure the
power can not be inadvertently energized. When
necessary to work with live electrical components,
have a qualified licensed electrician or other individual
who has been trained in handling live electrical
components perform these tasks. Failure to follow all of
the recommended safety warnings provided, could
result in death or serious injury.

WARNING
Overheating or Flooding Could Cause Fire
or Explosion!
Overheating or flooding (where any part of the duct
furnace has been under water) could result in fire or
explosion. Should overheating occur, or the gas supply
fails to shut off, shut off the manual gas valve to the
duct furnace before shutting off the electrical supply.
Do not use the duct furnace if any part has been under
water. Immediately call a qualified service technician to
inspect the duct furnace and replace any gas control
which has been underwater. Failure to follow these
recommendations could result in death or serious
injury.

WARNING
Hazardous Gases and Flammable
Vapors!
Exposure to hazardous gases from fuel substances
have been shown to cause cancer, birth defects or
other reproductive harm. Improper installation,
adjustment, alteration, service or use of this product
could cause flammable mixtures. To avoid hazardous
gases and flammable vapors follow proper
installation and set up of this product and all
warnings as provided in this manual. Failure to follow
all instructions could result in death or serious injury.

GMND-SVX01B-EN

Trademarks
Trane and the Trane logo are trademarks of Trane in the
United States and other countries. All trademarks
referenced in this document are the trademarks of their
respective owners.
3M is a trademark of 3M Company; Dow Corning is a
registered trademark of Dow Corning Corporation.

Introduction
WARNING
Safety Alert!
You MUST follow all recommendations below. Failure
to do so could result in death or serious injury.

For Your Safety
The use and storage of gasoline or other flammable
vapors and liquids in open containers in the vicinity
of this appliance is hazardous.
If you smell gas:
1. Open windows.
2. Do not touch electrical switches.
3. Extinguish any open flame.
4. Immediately call your gas supplier from a
neighbor’s phone. Follow the gas supplier’s
instructions.

Approved For Use in California

WARNING
Toxic Hazard!
Install, operate and maintain unit in accordance with
manufacturer’s instructions to avoid exposure to fuel
substances or substances from incomplete combustion
which could result in death or serious illness. The state
of California has determined that these substances may
cause cancer, birth defects, or other reproductive harm.

Installer’s Responsibility
Installer Please Note: This equipment has been test fired
and inspected. It has been shipped free from defects from
our factory. However, during shipment and installation,
problems such as loose wires, leaks, or loose fasteners
may occur. It is the installer’s responsibility to inspect and
correct any problems that may be found.

Receiving Instructions
Inspect shipment immediately when received to
determine if any damage has occurred to the unit during
shipment. After the unit has been uncrated, check for any
visible damage to the unit. If any damage is found, the
consignee should sign the bill of lading indicating such
damage and immediately file claim for damage with the
transportation company.
Important:

It is the equipment owner’s responsibility to
provide any scaffolding or other apparatus
required to perform emergency service or
annual/periodic maintenance to this
equipment.

GMND-SVX01B-EN

Table of Contents
Warnings, Cautions and Notices . . . . . . . . . . 2

Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . .39

Model Number Descriptions . . . . . . . . . . . . . . 6
Indoor Gas Heating Units . . . . . . . . . . . . . . . 6
Horizontal Blower Assembly . . . . . . . . . . . . 6

General Information . . . . . . . . . . . . . . . . . . . . . 7
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
General Safety Information . . . . . . . . . . . . . 7
Identification of Parts . . . . . . . . . . . . . . . . . . 8

Unit Dimensions and Weights . . . . . . . . . . . 10
Installation: Mechanical . . . . . . . . . . . . . . . . . 12
Clearances . . . . . . . . . . . . . . . . . . . . . . . . . 12
Air Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Suspension . . . . . . . . . . . . . . . . . . . . . . . . 14
Nozzle Assembly . . . . . . . . . . . . . . . . . . . 14

Installation: Piping . . . . . . . . . . . . . . . . . . . . . . 16
Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Pipe Sizing . . . . . . . . . . . . . . . . . . . . . . . . 16

Pipe Installation . . . . . . . . . . . . . . . . . . . . . . 17
Installation: Venting . . . . . . . . . . . . . . . . . . . 18
Combustion Air Venting and Piping . . . . 18
Exhaust Venting . . . . . . . . . . . . . . . . . . . . 19

Installation: Concentric Vent Terminal . . . 21
Horizontal Termination . . . . . . . . . . . . . . 21
Vertical Termination . . . . . . . . . . . . . . . . . 22

Installation: Electrical . . . . . . . . . . . . . . . . . . . 24
Electrical Connections . . . . . . . . . . . . . . . . . 24
Thermostat Wiring and Location . . . . . . 24

Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Gas Equipment Start-Up . . . . . . . . . . . . . . . 30

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Periodic Service . . . . . . . . . . . . . . . . . . . . 31
Installation Instructions for Field Replacement of Power Venter Motor . . . . . . . . . . 33
How to Order Replacement Parts . . . . . . 34

Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . 35
GMND-SVX01B-EN

Model Number Descriptions
Indoor Gas Heating
Units

Digit 13 — Rooftop Heating Unit
Motor Selection

Note: All units are AGA approved. For
CGA approved units, contact Air
Handling Product Support.

Digit 14 — Rooftop Fan Section

Digit 1 — Gas Heating
Equipment
G

Gas Heating Equipment

Digit 2 — Product Type
M =

Separated Combustion Indoor
Duct Furnace

Digit 3 — Fuel
N
P

=
=

Natural Gas
LP Gas (Propane)

Digit 4 — Development
Sequence
D

Fourth Generation

Digits 5, 6, 7 — Input Capacity
Single Furnace

None (Indoor Unit and Rooftop
Duct Furnace)
None (Indoor Unit and Rooftop
Duct Furnace)

Digit 15 — Miscellaneous
Options
0
A
B

=
=
=

D
F
G

=
=
=

None
#409 Stainless Steel Burners
Orifices For Elevation Above
2000 Feet (Specify Elevation)
#409 Stainless Steel Draft
Diverter
Summer-Winter Switch
Horizontal Louvers
Horizontal and Vertical Louvers

Horizontal Blower
Assembly
Digit 1, 2, 3 — Horizontal
Blower Assembly
Digit 4 — Development
Sequence
C

Third Generation

Digit 5, 6 — Blower Size
15
20
30
45

=
=
=
=

Nominal 1500 cfm
Nominal 2000 cfm
Nominal 3000 cfm
Nominal 4500 cfm

Digit 7 — Transition Size
(Specifies Duct Furnace Size)
0

None

100 MBh

225 MBh

125 MBh

250 MBh

150 MBh

300 MBh

175 MBh

350 MBh

200 MBh

400 MBh

010 =

100 MBh

022 =

225 MBh

012 =

125 MBh

025 =

250 MBh

015 =

150 MBh

030 =

300 MBh

017 =

175 MBh

035 =

350 MBh

115/60/1

230/60/3

020 =

200 MBh

040 =

400 MBh

230/60/1

460/60/3

208/60/3

Digit 8 — Main Power Supply

115/60/1

230/60/3

Digit 9 — Motor Horsepower

230/60/1

460/60/3

1/3 hp

1 hp

208/60/3

575/60/3

1/2 hp

1-1/2 hp

3/4 hp

2 hp

Digit 9 — Gas Control Option
D

Single-Stage, Intermittent Pilot
Ignition
Two-Stage, Intermittent Pilot
Ignition
Electronic Modulating with
Room
T-Stat, Intermittent Pilot Ignition
Electronic Modulating with
Duct-Stat, Intermittent Pilot
Ignition
Electronic Modulating with
External 4–20 mA Input
Electronic Modulating with
External 0–10 Vdc Input
Single Stage Direct Spark
Ignition
Two-Stage, Direct Spark Ignition

Digit 10 — Design Sequence
D

Fourth Design

Digit 11 — Miscellaneous
Options
0
1
3

=
=
=

None
Insulation
Totally Enclosed Motor

Digit 10 — Design Sequence
G

Seventh Design

Digit 11 — Heat Exchanger
Material
1
3

=
=

Aluminized Steel
#321 Stainless Steel

Digit 12 — Rooftop
Arrangements
0
6

None (Indoor Unit)
GMND-SVX01B-EN

General Information
Description
The duct furnace design is certified by ETL for use with
natural and LP (propane) gases. ANSI and NFPA Standards
as well as Canadian installation codes referred to in this
manual are the ones that were applicable at the time that
the design was certified. In addition, the duct furnace may
be installed on the downstream side of a cooling coil,
without need of a bypass duct.
If the unit is to be installed at an altitude exceeding
2,000 feet (610 m) above sea level, derate the input by
4 percent for each 1,000 foot (305 m) rise above sea level.
Special orifices are required for installations above
2,000 feet (610 m).
When units are installed in Canada, any reference to
derations at altitudes in excess of 2000 feet (610 m) are to
be ignored. At altitudes of 2000 to 4500 feet (610 to
1372 m), the units must be orificed to 90 percent of the
normal altitude rating, and be so marked in accordance
with the ETL certification.

Appliances and Equipment” or CGA-B149.2
“Installation Codes for Propane Gas Burning
Appliances and Equipment”. These duct furnaces
have been designed and certified to comply with
CGA 2.6. Also see sections on installation in
“Aircraft Hangers,” p. 12 and “Public Garages,”
p. 12.
•

Do not alter the duct furnace in any way or
damage to the unit and/or severe personal injury
or death could occur!

•

Turn off the gas supply and disconnect all
electric power, including remote disconnects
before servicing unit. Follow proper lockout/
tagout procedures to ensure the power can not
be inadvertently energized and the gas can not
be inadvertently turned on. Failure to turn off
gas or disconnect power before servicing could
result in death or serious injury.

•

Follow installation instructions CAREFULLY to
avoid creating unsafe conditions. All wiring
should be done and checked by a qualified
electrician, using copper wire only. All external
wiring must conform to applicable local codes
and to the latest edition of the National
Electrical Code ANSI/NFPA No. 70.

•

All gas connections should be made and leaktested by a suitably qualified individual, per
instructions in this manual. Also follow
procedures listed in “Gas Equipment Start-Up,”
p. 30.

•

Use only the fuel for which the duct furnace is
designed (see rating plate). Using LP gas in a
heater that requires natural gas, or vice versa,
will create the risk of gas leaks, carbon
monoxide poisoning and explosion.

General Safety Information
Important:

This product must be installed by a licensed
plumber or gas fitter when installed within
the Commonwealth of Massachusetts.

WARNING
Safety Alert!
You MUST follow all recommendations below. Failure
to do so could result in death or serious injury.
•

Installation must be made in accordance with
local codes, or in absence of local codes with the
latest edition of ANSI Standard Z223.1 (N.F.P.A.
No. 54) National Fuel Gas Code.
All of the ANSI and NFPA Standards referred to
in these installation instructions are those that
were applicable at the time the design of this
appliance was certified. The ANSI Standards are
available from the American National Standards
Institute, INC.,11 West 42nd Street, New York,
NY., 10036 or www.ansi.org. The NFPA
Standards are available from the National Fire
Protection Association, Batterymarch Park,
Quincy, MA 02269. These duct furnaces are
designed for use in airplane hangars when
installed in accordance with current ANSI/NFPA
No. 409 and in public garages when installed in
accordance with current NFPA No. 88A and
NFPA No. 88B.
If installed in Canada, the installation must
conform with local building codes, or in absence
of local building codes, with CGA-B149.1
“Installation Codes for Natural Gas Burning

GMND-SVX01B-EN

Important:

Do not attempt to convert the furnace
for use with a fuel other than the one
intended. Such conversion is
dangerous, as it could create the risks
listed previously.

•

Make certain that the power source conforms to
the electrical requirements of the furnace.

•

All field-installed wiring must be completed by
qualified personnel. All field-installed wiring
must comply with NEC and applicable local
codes. Failure to follow this instruction could
result in death or serious injuries.

•

Special attention must be given to any
grounding information pertaining to this duct
furnace. To prevent the risk of electrocution, the
furnace must be securely and adequately
grounded. This should be accomplished by
connecting a grounded conductor between the
service panel and the furnace. To ensure a proper
7

General Information
ground, the grounding means must be tested by
a qualified electrician.
•

Do not insert fingers or foreign objects into the
furnace or its air moving device. Do not block or
tamper with the heater in any manner while in
operation or just after it has been turned off, as
some parts may be hot enough to cause injury.

•

This furnace is intended for general heating
applications ONLY. It must NOT be used in
potentially dangerous locations such as
flammable, explosive, chemical-laden or wet
atmospheres.

•

Identification of Parts
Figure 1.

Combustion chamber

In cases in which property damage may result
from malfunction of the furnace, a backup
system or a temperature sensitive alarm should
be used.
When connecting to existing gas lines be sure to
valve off the gas supply ahead of connection
point. To avoid explosion or possible fire, always
purge all residual gas from piping before cutting
into existing line or removing threaded fittings.
Failure to remove all gas vapors could result in
death or serious injury or equipment or propertyonly-damage.

5
2
3

Gas valve

Air shutters

Main burners

Pilot assy.

Retainer spring

Manifold

Unless otherwise specified, the following conversions
may be used for calculating SI unit measurements:
1 foot = 0.305 m
1 inch = 25.4 mm
1 psig = 6.894 kPa
1 pound = 0.453 kg
1 gallon = 3.785 L

1 inch water column = 0.249 kPa
1 meter/second = FPM ÷ 196.8
1 liter/second = CFM x 0.472
1000 Btu per hour = 0.293 kW
1000 Btu/Cu. Ft. = 37.5 MJ/m3
1 cubic foot = 0.028 m3

GMND-SVX01B-EN

General Information
Figure 2.

Internal furnace assembly

3
1.

Flue Collector

Heat Exchanger

Burner Drawer

GMND-SVX01B-EN

Unit Dimensions and Weights
Table 1.
Unit Size
100
125
150
175
200
225
250
300
350
400

Specification data: Separated Combustion Duct Furnace
A
in. (mm)
17-7/8
(454)
20-5/8
(524)
20-5/8
(524)
23-3/8
(594)
26-1/8
(664)
28-7/8
(733)
31-5/8
(803)
37-1/8
(943)
42-5/8
(1083)
48-1/8
(1222)

B
in. (mm)
15-1/2
(394)
18-1/4
(464)
18-1/4
(464)
21
(533)
23-3/4
(603)
26-1/2
(673)
29-1/4
(743)
34-3/4
(883)
40-1/4
(1022)
45-3/4
(1162)

C
D (Dia.)(a)
in. (mm) in. (mm)
17-1/8
4
(435)
(102)
19-7/8
4
(505)
(102)
19-7/8
4
(505)
(102)
22-5/8
4
(575)
(102)
25-3/8
5
(645)
(127)
28-1/8
5
(714)
(127)
30-7/8
5
(784)
(127)
36-3/8
6
(924)
(152)
41-7/8
6
(1064)
(152)
47-3/8
6
(1203)
(152)

Gas Inlet
in.
Nat.
LP
1/2
1/2
1/2

1/2

3/4

1/2 or 3/4

3/4

1/2 or 3/4

3/4

1/2 or 3/4

3/4

1/2 or 3/4

3/4

1/2 or 3/4

Weight
lb (kg)
161
(73)
180
(82)
188
(85)
207
(93)
227
(103)
246
(116)
266
(121)
305
(138)
344
(156)
383
(174)

(a) “D” dia. equals the air inlet opening and the flue discharge opening.

Figure 3.

Dimensions, standard units

GMND-SVX01B-EN

Unit Dimensions and Weights
Table 2.

Performance data

Input
MAX
MIN
Output
MIN
Temp. Rise
P.D.
MAX
Temp. Rise
P.D.
Unit Size MBh (kW) MBh (kW) MBh (kW) cfm (m3/s)
°F (°C)
in. of H2O (kPa)
cfm (m3/s)
°F (°C)
in. of H2O (kPa)
100
100
50
80
822
90
0.10
3,700
20
2.03
(29.3)
(14.6)
(23.4)
(0.388)
(50)
(0.02)
(1.746)
(11)
(0.51)
125
125
62.5
100
1,028
90
0.09
4,625
20
1.92
(36.6)
(18.3)
(29.3)
(0.485)
(50)
(0.02)
(2.183)
(11)
(0.48)
150
150
75
120
1,233
90
0.09
5,550
20
1.81
(43.9)
(22.0)
(35.1)
(0.582)
(50)
(0.02)
(2.620)
(11)
(0.45)
175
175
87.5
140
1,439
90
0.09
6,475
20
1.86
(51.2)
(25.6)
(41.0)
(0.679)
(50)
(0.02)
(3.056)
(11)
(0.46)
200
200
100
160
1,645
90
0.09
7,401
20
1.90
(58.6)
(29.3)
(46.9)
(0.776)
(50)
(0.02)
(3.493)
(11)
(0.47)
225
225
112.5
180
1,850
90
0.09
8,326
20
1.93
(65.9)
(32.9)
(52.7)
(0.873)
(50)
(0.02)
(3.930)
(11)
(0.48)
250
250
125
200
2,056
90
0.09
9,251
20
1.96
(73.2)
(36.6)
(58.6)
(0.970)
(50)
(0.02)
(4.366)
(11)
(0.49)
300
300
150
240
2,467
90
0.10
11,101
20
2.00
(87.8)
(43.9)
(70.3)
(1.164)
(50)
(0.02)
(5.240)
(11)
(0.50)
350
350
175
280
2,878
90
0.10
12,951
20
2.02
(102.5)
(51.2)
(82.0)
(1.358)
(50)
(0.02)
(6.113)
(11)
(0.50)
400
400
200
320
3,289
90
0.10
14,801
20
2.05
(117.1)
(58.6)
(93.7)
(1.552)
(50)
(0.02)
(6.986)
(11)
(0.51)
Note: Ratings are shown for elevations up to 2,000 feet (610 m) above sea level. Above 2,000 feet (610 m), input must be derated 4 percent for each
1,000 feet (305 m) above sea level. When units are installed in Canada, any reference to derations at altitudes in excess of 2,000 feet (610 m) are
to be ignored. At altitudes of 2,000 to 4,500 feet (610 to 1,372 m), the units must be orificed to 90 percent of the normal altitude rating, and be so
marked in accordance with the ETL certification.

Figure 4.

Temperature rise and pressure drop graph

GMND-SVX01B-EN

Installation: Mechanical
NOTICE:
Equipment Damage!
Do not install duct furnaces in corrosive or flammable
atmospheres! Premature failure of, or severe damage to
the unit could result! Avoid locations where extreme
drafts can affect burner operation. Duct furnaces must
not be installed in locations where air for combustion
would contain chlorinated, halogenated or acidic
vapors. If located in such an environment, premature
failure of the unit could occur!
Note: Furnace sizing should be based on heat loss
calculations where the furnace output equals or
exceeds heat loss.

Aircraft Hangers. Separated Combustion must be
installed in aircraft hangars as follows: in aircraft hangars,
duct furnaces must be at least 10 feet (3.0 m) above the
upper surface of wings or engine enclosures of the highest
aircraft to be stored in the hangar, and 8 feet (2.4 m) above
the floor in shops, offices and other sections of the hangar
where aircraft are not stored or housed. In Canada,
installation is suitable in aircraft hangars when acceptable
to the enforcing authorities.
Public Garages. In repair garages, duct furnaces must
be installed in a detached building or room separate from
repair areas as specified in the latest edition of NFPA 88B,
Repair Garages.
In parking structures, duct furnaces must be installed so
that the burner flames are located a minimum of 18 inches
(457 mm) above the floor or protected by a partition not
less than 18 inches (457 mm) high. Refer to the latest
edition of NFPA 88A, Parking Structures.
In Canada, installation must be in accordance with the
latest edition of CGA B149 “Installation Codes for Gas
Burning Appliances and Equipment.”

NOTICE:
Maintain Minimum Thermostat Setting!
Separated Combustion Duct Furnaces should not be
installed to maintain low temperatures and/or freeze
protection of buildings. A minimum of 50°F (10°C)
thermostat setting must be maintained. If duct furnaces
are operated to maintain lower than 50°F (10°C), hot
flue gases are cooled inside the heat exchanger to a
point where water condenses onto the heat exchanger
walls. The result is a mildly corrosive acid that
prematurely corrodes the aluminized heat exchanger
and can actually drip water down from the duct furnace
onto the floor surface. Additional duct furnaces should
be installed if a minimum 50°F (10°C) thermostat
setting cannot be maintained. Failure to follow these
recommendations could result in equipment or
property damage.

WARNING
Hazardous Gases and Flammable Vapors!
Exposure to hazardous gases from fuel substances
have been shown to cause cancer, birth defects or other
reproductive harm. Improper installation, adjustment,
alteration, service or use of this product could cause
flammable mixtures. To avoid hazardous gases and
flammable vapors follow proper installation and set up
of this product and all warnings as provided in this
manual. Failure to follow all instructions could result in
death or serious injury.

Clearances
Note: Increasing the clearance distances may be
necessary if there is a possibility of distortion or
discoloration of adjacent materials.

WARNING
Combustible Materials!
Maintain proper clearance between the unit heat
exchanger, vent surfaces, and combustible materials.
Refer to unit nameplate and installation instructions for
proper clearances. Improper clearances could result in a
fire hazard. Failure to maintain proper clearances could
result in death or serious injury or property damage.
Maintain adequate clearances around air openings into
combustion chamber:
Table 3.

Minimum clearances

Sides

18” (457 mm)

Top

6” (152 mm)

Bottom

25” (635 mm)

Flue

6” (152 mm)

Note: When the clearances required for accessibility are greater than the
minimum required safety clearances, the accessibility clearances
take precedence.

GMND-SVX01B-EN

Installation: Mechanical
Increasing the clearance distances may be necessary if
there is a possibility of distortion or discoloration of
adjacent materials.

Figure 5.

Recommended design for field installation of
ductwork for straight-through arrangement

Figure 6.

Recommended ductwork design for elbowed
arrangement

Accessibility
The Separated Combustion Duct Furnace is a bottom
service access type. Allow a minimum of 25 inches
(635 mm) at the bottom of the unit to facilitate servicing
the burners and pilot. Provision should also be made to
assure accessibility for recurrent maintenance purposes.
Atmospheres containing commercial solvents or
chlorinated hydrocarbons will produce corrosive acids
when coming in contact with the flames. This will greatly
reduce the life of the gas duct furnace and may void the
warranty. Avoid such areas.

WARNING
Fire Hazard!
If the gas duct furnace is to be used in a building
classified as having a hazardous atmosphere, the
installation must comply with the standards set by the
National Board of Fire Underwriters. Consult the
authorities having jurisdiction before starting the job.
Failure to follow recommendations could result in
death or serious injury.
The Separated Combustion Duct Furnace must be
installed on the positive pressure side of the air circulation
blower.

Ductwork
Properly designed and installed ductwork, providing a
uniformly distributed flow of air across the surfaces of the
heat exchanger, is essential to satisfactory unit
performance and life of the equipment.
All duct connection flanges/seams must be sealed to
prevent air leaks. Sealant/tape must be suitable for
temperatures 250°F (121°C) minimum.

NOTICE:
Use 90° Duct Connection Flanges!
Ducts must be properly connected to duct furnaces for
operation. Do not straighten the 90° duct connection
flanges on the duct furnaces. Straightening the 90° duct
connection flanges will affect the operation of the
furnace and will void the warranty.
If uniform air distribution is not obtained, install additional
baffles and/or turning vanes in the ductwork.
Figure 5 and Figure 6 illustrate recommended ductwork
designs for both the straight-through and elbowed air inlet
arrangements.

GMND-SVX01B-EN

Access panels large enough to observe smoke and
reflected light, and to detect the presence of leaks in the
heating equipment, are required both upstream and
downstream from gas duct furnaces. These panels must
be sealed to prevent air leaks. If allowed by local
regulations, install canvas connectors between the
ductwork and fan discharge opening to eliminate the
transmission of sound.

Air Flow
The installation is to be adjusted to obtain an air
throughput within the range specified on the appliance
rating plate.

Bypass
When a gas duct furnace is installed to operate in
conjunction with a summer air conditioning system, the
cfm air delivery of the system blower should be adjusted
to meet the design air volume requirements for cooling. If
this cfm delivery is greater than that required for heating,
resulting in a low air temperature rise, install a damper
13

Installation: Mechanical
bypass around the gas duct furnace to bypass a portion of
the air.

Suspension

Nozzle Assembly
Figure 7.

Typical four (4) point duct suspending
arrangement

WARNING
Heavy Objects!
Ensure that all hardware used in the suspension of each
duct furnace is capable of supporting the unit weight.
Failure to do so could result in unit falling off its
mounting location, which could result in death or
serious injury.

“S”
“S”

NOTICE:
Equipment Damage!
The Separated Combustion Duct Furnace must be hung
level from side to side and front to back, from four
suspension points provided at the top of the unit.
Failure to do so could result in poor performance and/
or premature failure of the unit. Refer to Figure 7, p. 14
for typical suspension arrangements.

WARNING

D4284

3/8-16 Treaded
Suspension Rod &
Jam Nut By Installer

Heavy Objects!
Make certain that the lifting methods used to lift the
duct furnace and the method of suspension used in the
field installation of the duct furnace are capable of
uniformly supporting the weight of the furnace at all
times. Make certain that the structure to which the
furnace is mounted is capable of supporting its weight.
Under no circumstances must the heater gas lines, the
venting system or the electrical conduit be used for
support. Failure to follow recommendations could
result in death, serious injury, or property damage.

Outside Jacket
Panel (Duct)

3/8-16 Speed Grip
Nut Retainer

D4285

Use the following procedure for assembling the 30-, 60-, or
90-degree nozzle assembly to your unit heater.
1. Remove the louvers and the cone springs from the unit
heater.
2. Remove the four (4) screws from the upper section of
the front of the unit heater and use these same screws
to temporarily attach the top bracket
(P/N 252-07948-00X).
a. Using the holes in the top bracket as a guide, predrill a 1/8” (0.125”) hole at each location across the
front panel of the unit heater.
b. Using the enclosed screws, permanently attach the
top bracket.
3. Remove the upper two (2) screws from the lower
section on the front of the unit heater. Repeat the
procedure described in Step 2 using the bottom
bracket (P/N 252-07949-00X).
4. Using the sixteen (16) 5/16-12 x 1/2 screws, attach the
left and right side panel (P/N 251-07944 and 251-07946)
to the unit heater using the holes to which the louvers
were attached.
5. Using the enclosed #8-18 x 1/2 screws and with the top
panel oriented such that the side with the larger holes

GMND-SVX01B-EN

Installation: Mechanical
is facing the unit heater, attach the top panel
(P/N 251-07942-00X) to the top bracket and the two (2)
side panels.
Note: The top panel must be attached so that the side
with the larger holes is facing the unit heater;
this is a requirement for later steps in this
installation procedure.
6. Using the enclosed #8-18 x 1/2 screws and with the
bottom panel oriented such that the side with the larger
holes is facing the unit heater, attach the bottom panel
(P/N 251-07943-00X) to the bottom bracket and the two
(2) side panels.
Note: The bottom panel must be attached so that the
side with the larger holes is facing the unit
heater; this is a requirement for later steps in
this installation procedure.
Note: For 90-degree nozzle assemblies, repeat Step 8
to create a second sub-assembly.
9. For 60- and 90-degree nozzle assemblies: Using the
enclosed #8-18 x 1/2 screws, attach the sub-assembly
created in Step 8 to the 30-degree assembly installed to
the unit (in Step 1 through Step 6 of this procedure).
Attach the corresponding panels (i.e., top panel to top
panel, right side panel to right side panel, etc).
Note: For 90-degree nozzle assemblies, install the
second sub-assembly by attaching it to the first
sub-assembly. Attach the corresponding panels
(i.e., top panel to top panel, right side panel to
right side panel, etc).

For 30-degree nozzle assemblies: Go to Step 10.

8. For 60- and 90-degree nozzle assemblies: Using the
enclosed #8-18 x 1/2 screws and with the top and
bottom panels oriented such that the sides with the
larger holes are facing the unit heater, create a
sub-assembly by attaching the top panel
(P/N 251-07942-00X) and the bottom panel
(P/N 251-07943-00X) to the left side panel
(P/N 251-07945) and to the right side panel
(P/N 251-07947).
Note: The top and bottom panels must be attached so
that the sides with the larger holes are facing
the unit heater; this makes the assembly easier.
10. Install the louvers and cone springs.

GMND-SVX01B-EN

Installation: Piping
Gas Piping
WARNING
Flammable Vapors!
When connecting to existing gas lines be sure to valve
off the gas supply ahead of connection point. To avoid
explosion or possible fire, always purge all residual gas
from piping before cutting into existing line or
removing threaded fittings. Failure to remove all gas
vapors could result in death or serious injury or
equipment or property-only damage.

Pipe Sizing
To provide adequate gas pressure to the gas duct furnace,
size the gas piping as follows:
1. Find the ft3/hr by using the following formula:
ft3/hr =

Input
Btu per ft3

2. Refer to Table 4, p. 17. Match “Length of Pipe” with
appropriate “Gas Input - Ft3/Hr” value. This value can
then be matched to the pipe size at the left of the table.
Example: It is determined that a 67 foot (20.4 m) run of
gas pipe is required to connect a 200 MBtu gas duct
furnace to a 1,000 Btu/ft3 (0.29 kW) natural gas supply.
200,000 Btu/hr
1,000 Btu/ft3

= 200 ft3/hr

Using Table 4, p. 17, a 1-inch pipe is needed.
Notes:
•

See “General Safety Information,” p. 7 for English/SI
(metric) unit conversion factors.

•

If more than one gas duct furnace is to be served by the
same piping arrangement, the total cubic feet per hour
input and length of pipe must be considered.

•

If the gas duct furnace is to be fired with LP gas, consult
the local LP gas dealer for pipe size information.

WARNING
Hazard of Explosion and Fire!
Heater installation for use with propane (LP gas) must
be made by a qualified LP Gas Dealer or LP Gas Installer
to ensure that all appropriate codes, installation
procedures, and precautions have been followed.
Failure to follow these instructions could result in death
or serious injury.
Before any connection is made to an existing line
supplying other gas appliances, contact the local gas
company to make certain that the existing line is of
adequate size to handle the combined load.

GMND-SVX01B-EN

Installation: Piping
Table 4.

Gas pipe size(a)

Nominal Internal
10
Iron Pipe Diameter,
Size, in.
in. (mm)
(3.0)
1/2

Length of Pipe, ft (m)
20
(6.1)

100

125

150

175

200

(9.1) (12.2) (15.2) (18.3) (21.3) (24.4) (27.4) (30.5) (38.1) (45.7) (53.3) (61.0)

0.622

175

120

(16)

(4.96)

(3.40)

(2.75)

(2.32)

(2.07)

(1.87)

(1.73)

(1.61)

(1.50)

(1.42)

(1.25)

(1.13)

(1.05)

(0.99)

0.824

360

250

200

170

151

138

125

118

110

103

(21)

(10.2)

(7.08)

(5.66)

(4.81)

(4.28)

(3.91)

(3.54)

(3.34)

(3.11)

(2.92)

(2.63)

(2.38)

(2.18)

(2.04)

1.049

680

465

375

320

285

260

240

220

205

195

175

160

145

135

(27)

(19.3)

(13.2)

(10.6)

(9.06)

(8.07)

(7.36)

(6.80)

(6.23)

(5.80)

(5.52)

(4.96)

(4.53)

(4.11)

(3.82)

1-1/4

1.380

1400

950

770

660

580

530

490

460

430

400

360

325

300

280

(35)

(39.6)

(26.9)

(21.8)

(18.7)

(16.4)

(15.0)

(13.9)

(13.0)

(12.2)

(11.3)

(10.2)

(9.20)

(8.50)

(7.93)

1-1/2

1.610

2100

1460

1180

990

900

810

750

690

650

620

550

500

460

430

(41)

(59.5)

(41.3)

(33.4)

(28.0)

(25.5)

(22.9)

(21.2)

(19.5)

(18.4)

(17.6)

(15.6)

(14.2)

(13.0)

(12.2)

2.067

3950

2750

2200

1900

1680

1520

1400

1300

1220

1150

1020

950

850

800

(53)

(112)

(77.9)

(62.3)

(53.8)

(47.6)

(43.0)

(39.6)

(36.8)

(34.5)

(32.6)

(28.9)

(26.9)

(24.1)

(22.7)

2-1/2

2.469

6300

4350

3520

3000

2650

2400

2250

2050

1950

1850

1650

1500

1370

1280

(63)

(178)

(123)

(99.7)

(85.0)

(75.0)

(68.0)

(63.7)

(58.0)

(55.2)

(52.4)

(46.7)

(42.5)

(38.8)

(36.2)

3.068

11000

7700

6250

5300

4750

4300

3900

3700

3450

3250

2950

2650

2450

2280

(78)

(311)

(218)

(177)

(150)

(135)

(122)

(110)

(105)

(97.7)

(92.0)

(83.5)

(75.0)

(69.4)

(64.6)

4.026

23000

15800

12800

10900

9700

8800

8100

7500

7200

6700

6000

5500

5000

4600

(102)

(651)

(447)

(362)

(309)

(275)

(249)

(229)

(212)

(204)

(190)

(170)

(156)

(142)

(130)

3/4

Notes:
1. Determine the required ft3/h by dividing the rated heater input by 1000. For SI / Metric measurements: Convert unit Btu/h to kilowatts. Multiply the
unit input (kW) by 0.0965 to determine m3/h.
2. FOR NATURAL GAS: Select the pipe size directly from the table.
3. FOR PROPANE GAS: Multiply the ft3/h (m3/h) value by 0.633; then use the table.
4. Refer to the metric conversion factors listed in “General Safety Information,” p. 7 for more SI unit measurements/conversions.
(a) Maximum capacity of pipe in cubic feet of gas per hour (cubic meters per hour) for gas pressures of 0.5 psig (3.5 kPa) or less, and a pressure drop of
0.5 inch water column (124.4 Pa) (based on a 0.60 specific gravity gas).

Pipe Installation
1. Install the gas piping in accordance with applicable
local codes.
2. Check gas supply pressure. Each duct furnace must be
connected to a gas supply capable of supplying its full
rated capacity as specified in Table 5, p. 18. A field LP
tank regulator must be used to limit the supply
pressure to maximum of 14 in. wc (3.5 kPa). All piping
should be sized in accordance with the latest edition of
ANSI Standard Z223.1 National Fuel Gas Code; in
Canada, according to CGA-B149. See Table 1,
p. 10Table 4, p. 17, and Table 5, p. 18 for correct gas
piping size.
If gas pressure is excessive on natural gas applications,
install a pressure regulating valve in the line upstream
from the main shutoff valve.

WARNING
Hazard of Explosion!
Adequately support the piping to prevent strain on the
gas manifold and controls. To prevent explosion, fire, or
gas leaks, support piping so that piping does not sag or
put pressure on the burners internal to the unit. Failure
to follow these recommendations could result in death
or serious injury or equipment or property-onlydamage.
3. To prevent the mixing of moisture with gas, run the
take-off piping from the top, or side, of the main.
4. Duct furnaces are shipped with a combination valve
which includes:
a. Manual “A” valve
b. Manual “B” valve
c. Solenoid valve
d. Pilot safety
e. Pressure regulator

GMND-SVX01B-EN

Installation: Piping
Pipe directly in to combination valve (see Figure 8,
p. 18).
5. A 1/8 in. N.P.T. plugged tapping, accessible for test
gauge connection, must be installed immediately
upstream of the gas supply connection to the
appliance.
6. Provide a drip leg in the gas piping near the gas duct
furnace. A ground joint union and a manual gas shutoff
valve should be installed ahead of the unit heater
controls to permit servicing. The manual shutoff valve
must be located external to the jacket (see Figure 8,
p. 18).
7.

The appliance must be isolated from the gas supply piping
system by closing its individual manual shutoff valve
during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2 psig
(3.5 kPa).
Table 5.
Gas Type

Natural Gas

Manifold Pressure

3.5 in. wc

10.5 in. wc

(0.9 kPa)

(2.6 kPa)

14.0 in. wc Max.

(3.5 kPa)

Supply Inlet Pressure

Make certain that all connections have been
adequately doped and tightened.

NOTICE:

Gas piping requirements(a)
Propane (LP) Gas

5.5 in wc Min.

13.0 in wc Min.

(1.4 kPa)

(3.2 kPa)

(a)

Overtightening!

Installation: Venting

Do not overtighten the inlet gas piping into the valve.
This may cause stresses that could crack the valve!

Combustion Air Venting and Piping

Note: Use pipe joint sealant resistant to the action of
liquefied petroleum gases regardless of gas
conducted.

WARNING
Exhaust Fumes!
Each duct furnace MUST have its own combustion air
system and MUST NOT be connected to other air intake
systems. To prevent exhaust fumes from being pulled
into the air intake system or improper heating, ensure
that the duct furnace has its own combustion air
system and is not connected to other air intake
systems. Failure to follow these recommendations
could result in death or serious injury or equipment
damage.

WARNING
Carbon Monoxide!
Your venting system must not be blocked by any snow,
snow drifts, or any foreign matter. Inspect your venting
system to ensure adequate ventilation exists at all
times! A blocked venting system could result in carbon
monoxide poisoning. Symptoms of such condition
include grogginess, lethargy, inappropriate tiredness, or
flu-like symptoms. Failure to follow these
recommendations could result in death or serious
injury.

D3631C

The appliance and its individual shutoff valve must be
disconnected from the gas supply piping system during
any pressure testing of that system in excess of 1/2 psig
(3.5 kPa).

GMND-SVX01B-EN

Installation: Piping

WARNING
Risk of Fire and Carbon Monoxide
Poisoning with Improper Piping!
Never use pipe of a diameter other than that specified
in Table 1, p. 10 (“D” dia. flue opening)! To prevent pipe
from melting and introducing exhaust fumes into the
air supply, never use PVC, ABS or any other nonmetallic pipe for venting! Failure to follow these
recommendations could result in death or serious
injury or equipment damage.
1. The combustion air system installation must be in
accordance with the latest edition of (N.F.P.A. 54) ANSI
Z223.1 National Fuel Gas Code. In Canada, installation
must be in accordance with CGA-B149.1 “Installation
Code for Natural Gas Burning Appliances or
Equipment” and CGA-B149.2 “Installation Code for
Propane Burning Appliances and Equipment”.
2. A Breidert Type L or Fields inlet cap, furnished by the
customer, must be installed at the termination point of
the combustion air system (see Figure 9, p. 21 and
Figure 10, p. 21).
Note: The top of the inlet cap is to be no less than
12 inches (305 mm) from the top of the exhaust
vent cap (see Figure 9, p. 21 and Figure 10,
p. 21).
3. Use single wall pipe constructed of 26 gauge
galvanized steel or a material of equivalent durability
and corrosion resistance for the combustion air
system. For installation in Canada, use pipe
constructed from 0.025-inch thick aluminum or 0.018inch thick stainless steel.
4. Long runs of single wall combustion air piping passing
through an unheated space may require insulating if
condensation becomes noticeable.
5. The combustion air system must be installed to
prevent collection of condensate. Pitch horizontal
pipes downward 1/4 inch per foot (21 mm/m) toward
the inlet cap to facilitate drainage. Vertical combustion
air pipes should be arranged as depicted in Figure 9,
p. 21.
6. The equivalent length of the combustion air system
must not be less than five feet (1.5 m) and must not
exceed 50 feet (15.2 m). Equivalent length equals the
total length of straight pipe, plus 15 feet (4.6 m) for
each 90-degree elbow and five feet (1.5 m) for each
45-degree elbow.
Note: For optimum performance, keep the
combustion air system as straight as possible.
7.

Each slip joint must be secured with at least three
corrosion resistant screws. Two full turns of 3M™ #425
Aluminum Foil Tape or its equivalent must then be
used to seal each joint. General Electric RTV-108, Dow

GMND-SVX01B-EN

Corning® RTV-732 or an equivalent may be used
instead of the tape.
8. For horizontal combustion air systems longer than five
feet (1.5 m), the system must be supported from
overhead building structures at three-foot (1-m)
intervals.

Exhaust Venting
WARNING
Carbon Monoxide!
Never operate duct furnaces without combustion air
and flue gas piping in place. Each unit MUST have its
own combustion air system and MUST NOT be
connected to other vent systems or to a chimney. Your
venting system must not be blocked by any snow, snow
drifts, or any foreign matter. Inspect your venting
system to ensure adequate ventilation exists at all
times! Failure to follow these recommendations could
result in death or serious injury.

Installation: Piping
4. Any run of single wall vent pipe passing through an
unheated space must be insulated with an insulation
suitable to 550°F (288°C).
5. The combustion and exhaust vent air systems must be
installed to prevent collection of condensate. Pitch
horizontal pipes downward 1/4 inch per foot (21 mm/
m) toward the terminal cap to facilitate drainage (see
Figure 11, p. 21). Vertical vent pipes should be
arranged as depicted in Figure 9, p. 21.
6. The equivalent length of the vent system must not be
less than five feet (1.5 m) and must not exceed 50 feet
(15.2 m). Equivalent length equals the total length of
straight pipe plus 15 feet (4.6 m) for each 90-degree
elbow and five feet (1.5 m) for each 45-degree elbow.
7.

Each slip joint must be secured with at least three
corrosion resistant screws. Two full turns of 3M™ #425
Aluminum Foil tape or its equivalent must then be
used to seal each joint. General Electric RTV-108, Dow
Corning® RTV-732, or an equivalent may be used
instead of the tape.

8. For horizontal vent systems longer than five feet
(1.5 m), the system must be supported from overhead
building structures at three-foot (1-m) intervals.
9. The exhaust vent system must remain at a minimum of
six inches (152 mm) from all combustible materials.
Any part of the vent system that passes through a
combustible material must be properly insulated.
Note: Increasing the clearance distances may be
necessary if there is a possibility of distortion or
discoloration of adjacent materials.
For a VERTICAL vent pipe section that passes through
a floor or roof, an opening four inches (102 mm)
greater in diameter is required. The opening must be
insulated and flashed in accordance with applicable
installation codes.
A HORIZONTAL section of an exhaust vent system that
passes through a combustible wall must be
constructed and insulated as shown in Figure 12, p. 21.
10. The top of a VERTICALLY VENTED exhaust system
must extend at least three feet (1 m) above the roof
surface that it passes through. The point of termination
for a HORIZONTALLY VENTED exhaust system must be
at least 12 inches (305 mm) from the exterior wall that
it passes through. In addition, the termination point
must be at least three feet (1 m) above the snow line,
more than six feet (2 m) from the combustion air inlet
of another appliance, more than three feet (1 m) from
any building opening, and more than four feet (1.3 m)
from, and not directly above, any electric meter,
regulator, or relief equipment (refer to Figure 10, p. 21
and Figure 12, p. 21).

GMND-SVX01B-EN

Installation: Piping
Figure 9.

Vertical intake/vent installation

Figure 12. Horizontal vent installation

Installation: Concentric Vent
Terminal
WARNING
Hazardous Service Procedures!

Figure 10.

Vertical vent installation

The maintenance and troubleshooting procedures
recommended in this manual could result in exposure
to electrical, mechanical or other potential safety
hazards. Always refer to the safety warnings provided
throughout this manual concerning these procedures.
When possible, disconnect all electrical power
including remote disconnect and discharge all energy
storing devices such as capacitors before servicing.
Follow proper lockout/tagout procedures to ensure the
power can not be inadvertently energized. When
necessary to work with live electrical components, have
a qualified licensed electrician or other individual who
has been trained in handling live electrical components
perform these tasks. Failure to follow all of the
recommended safety warnings provided, could result in
death or serious injury.

Horizontal Termination

Figure 11.

Horizontal intake/vent locations

GMND-SVX01B-EN

Select a location on an outside wall for the vent terminal.
In most applications, the terminal should be on level with
the flue outlet of the unit, less 1/4 inch per foot pitch for
condensate drainage toward the outside of the building
(see Figure 13, p. 22).

Installation: Piping
Figure 13. Horizontal concentric venting
Size pipes
according to
Table 1, p. 10.

Insert the pipes through the wall and fasten the adapter
box in place. Flash and/or caulk 8-inch pipe on outside wall
(see Figure 14, p. 22, Step 3).
Install the inlet air screen on the 8-inch pipe and fasten with
sheet metal screws. Install the flue terminal on the 5-inch
pipe and fasten in place (see Figure 14, p. 22, Step 4).
Figure 14. Horizontal concentric venting—installation

The location of the vent terminal must be in accordance
with the National Fuel Gas Code ANSI Z223.1 in the U.S. or
the National Gas Installation Code CAN/CGA-B149.1 or the
Propane Gas Installation Code CAN/CGA-149.2 in Canada.
Minimum clearance are as follows:
Table 6.

Horizontal concentric venting—minimum
clearance
Minimum Clearance

Object

U.S.

Canada

Forced air inlet within
10 feet

3 feet above

6 feet

4 feet below
Door, window or gravity
air inlet or combustion air 4 feet horizontally
inlet for other appliance
1 foot above

12 inches for
100,000 Btu/h input
or less. 3 feet for
input exceeding
100,000 Btu/h.

Adjacent public walkways 7 feet above grade

7 feet above grade

Above grade level

1 foot

In Canada, a vent shall not terminate above a meter/
regulator assembly within 3 feet horizontally of the
vertical center line of the regulator nor within 6 feet of any
gas service regulator vent outlet.
Cut a hole through the wall for an 8-inch combustion air
pipe. Install thimble if required by local codes or type of
wall construction (see Figure 14, p. 22, Step 1).
Fasten a length of 5-inch pipe to the exhaust connection of
the concentric adapter with sheet metal screws. Use at
least three corrosion-resistant screws per joint. Seal all
joints with high temperature silicone sealant. The
concentric adapter box may be fastened directly to the wall
or spaced away from the wall using suitable brackets
(field-supplied). Before mounting the box, cut a length of
8-inch pipe so that it will protrude 2 inches through the
wall when the box is mounted in position. Fasten the
8-inch pipe to the combustion air inlet connection of the
concentric adapter and seal the joint. Add an additional 5inch pipe, if necessary, so that the base of the exhaust cap
will be 16 to 24 inches from the combustion air inlet (see
Figure 14, p. 22, Step 2).

Connect the flue pipe and the combustion air pipe from the
concentric adapter to the unit. The pipe must be single wall
26-gauge or heavier galvanized steel or a material of
equivalent durability and corrosion resistance. The pipe
diameter must be listed under inlet and flue size in Table 1,
p. 10. The equivalent length of the exhaust vent pipe must
be a minimum of 5 feet and a maximum of 50 feet. The
equivalent length equals the total length of straight pipe
plus 15 feet for each 90-degree elbow and 5 feet for each
45-degree elbow. Secure each joint with a minimum of
three corrosion resistant screws. Seal all joints of the
exhaust vent pipe with two full turns of 3M #425
Aluminum Foil Tape or its equivalent suitable for 550°F or
high temperature silicone sealant. Seal all joints of the
combustion air inlet pipe with two full turns of duct tape or
aluminum foil tape or silicone sealant.

Vertical Termination
Select a location on the roof for the vent terminal, ensuring
adequate space inside for the concentric vent box. The
terminal must be at least 6 feet from any wall or adjoining
building (see Figure 15, p. 23).

GMND-SVX01B-EN

Installation: Piping
Figure 15. Vertical concentric venting

Figure 16. Vertical concentric venting—installation

Size pipes
according to
Table 1, p. 10.

Cut a hole through the roof for an 8-inch combustion air
pipe. Fasten a length of 5-inch pipe to the exhaust
connection of the concentric adapter with sheet metal
screws. Use at least three screws per joint. Seal all joints
with high temperature silicone sealant. The concentric
adapter box is to be suspended from the underside of the
roof using suitable brackets (field-supplied). Before
mounting the box, cut a length of 8-inch pipe so that
dimension A (see Figure 16, p. 23, Step 1), is equal to the
roof thickness plus 18 inches or the roof thickness plus the
expected snow depth, whichever is greater. Fasten the
8-inch pipe to the combustion air inlet connection of the
concentric adapter and seal the joint. Add an additional
5-inch pipe to extend at least 20 inches above the top of the
8-inch pipe.
Insert the pipe through the roof and fasten the adapter box
in place (see Figure 16, p. 23, Step 2).
Flash and/or caulk the 8-inch pipe to the roof (see
Figure 16, p. 23, Step 3).
Install the inlet air cap on the 8-inch pipe and fasten with
sheet metal screws. Install the flue terminal on the 5-inch
pipe and fasten in place. Seal the joint between the 5-inch
pipe and the inlet air cap with silicone sealant to prevent
the entry of water (see Figure 16, p. 23, Step 4).

GMND-SVX01B-EN

Connect the flue pipe and the combustion air pipe from the
concentric adapter to the unit. Pipe must be single wall
26-gauge or heavier galvanized steel or a material of
equivalent durability and corrosion resistance. Pipe
diameter must be as listed under inlet and flue size in
Table 1, p. 10. The equivalent length of the exhaust vent
pipe must be a minimum of 5 feet and a maximum of
50 feet. The equivalent length equals the total length of
straight pipe plus 15 feet for each 90-degree elbow and
5 feet for each 45-degree elbow. Secure each joint with a
minimum of three corrosion-resistant screws. Seal all
joints of the exhaust vent pipe with two full turns of 3M
#425 Aluminum Foil Tape or its equivalent suitable for
550°F or high temperature silicone sealant. Seal all joints
of the combustion air inlet pipe with two full turns of duct
tape or aluminum foil tape or silicone sealant. Do not
enclose the exhaust vent pipe or run the pipe within
6 inches of combustible material.

Installation: Electrical
Electrical Connections
WARNING
Hazardous Service Procedures!
The maintenance and troubleshooting procedures
recommended in this section of the manual could result
in exposure to electrical, mechanical or other potential
safety hazards. Always refer to the safety warnings
provided throughout this manual concerning these
procedures. When possible, disconnect all electrical
power including remote disconnect and discharge all
energy storing devices such as capacitors before
servicing. Follow proper lockout/tagout procedures to
ensure the power can not be inadvertently energized.
When necessary to work with live electrical
components, have a qualified licensed electrician or
other individual who has been trained in handling live
electrical components perform these tasks. Failure to
follow all of the recommended safety warnings
provided, could result in death or serious injury.

WARNING
Hazardous Voltage and Gas!
Turn off the gas supply and disconnect all electric
power, including remote disconnects before servicing
unit. Follow proper lockout/tagout procedures to
ensure the power can not be inadvertently energized
and the gas can not be inadvertently turned on. Failure
to turn off gas or disconnect power before servicing
could result in death or serious injury.

WARNING
Proper Field Wiring and Grounding
Required!
All field wiring MUST be performed by qualified
personnel. Improperly installed and grounded field
wiring poses FIRE & ELECTROCUTION hazards. To
avoid these hazards, you MUST follow requirements for
field wiring installation and grounding as described in
NEC and your local/state electrical codes. Failure to
follow these requirements could result in death or
serious injury.

NOTICE:
Use Copper Conductors Only!
Unit terminals are not designed to accept other types
of conductors. Failure to use copper conductors could
result in equipment damage.
It is recommended that the electrical power supply to each
duct furnace be provided by a separate, fused, and
permanently live electrical circuit. A disconnect switch of
suitable electrical rating should be located as close to the
gas valve as possible. Each duct furnace must be
electrically grounded in accordance with the latest edition
of the National Electric Code, ANSI/NFPA No. 70 or CSA
Standard C22.1. Sample wiring connections are depicted
in Figure 22, p. 39 and Figure 23, p. 40.

Thermostat Wiring and Location
Note: The thermostat must be mounted on a vertical,
vibration-free surface, free from air currents, and in
accordance with the furnished instructions.
Mount the thermostat approximately 5 feet (1.5 m) above
the floor in an area where it will be exposed to a free
circulation of average temperature air. Always refer to the
thermostat instructions as well as our unit wiring diagram,
and wire accordingly. Avoid mounting the thermostat in
the following locations:
1. Cold areas—Outside walls or areas where drafts may
affect the operation of the control.
2. Hot areas—Areas where the sun’s rays, radiation, or
warm air currents may affect control operation.
3. Dead areas—Areas where air cannot circulate freely,
such as behind doors or in corners.
Note: Thermostat wires tagged “W” and “G” must be
connected together except when using a general
purpose “SPDT” 24 Vac relay and a standard
thermostat with subbase, or when using
Honeywell T834H or T834N thermostats. Also refer
to Figure 17, p. 24 for other wiring connections.
Figure 17.

C1267G, thermostat wiring diagram

Standard units are shipped for use on 115 volt, 60 hertz
single phase electric power. The motor nameplate and
electrical rating of the transformer should be checked
before energizing the duct furnace electrical system. All
external wiring must conform to the latest edition of ANSI/
NFPA No. 70 National Electrical Code and applicable local
codes; in Canada, to the Canadian Electrical Code, Part 1
CSA Standard C22.1.

Thermostat Heat Anticipator Adjustments. The
initial heat anticipator setpoint should equal the
thermostat’s current amperage draw when the unit is
24

GMND-SVX01B-EN

Installation: Electrical
firing. This setpoint should be measured for the best
results. Use the recommended ranges as a guide. If further
information is needed, consult your thermostat
manufacturer’s instructions.
Recommended Heat Anticipator Setting Ranges:
25 ft. (7.6 m) T’stat
Wiring
0.85 to 0.90 A

50 ft. (15.2 m) T’stat Wiring
0.90 to 1.1 A Max. Setting on T’stat

Fan Time Delay Control
Leads from the fan time delay controls are factory wired to
the junction box. The fan control is a time delay relay
(approximately 45 seconds ON, 65 seconds OFF). The fan
control is rated at 17 amps.
Notes:
•

The start-up fan delay should not exceed 90 seconds
from a cold start.

•

For all wiring connections, refer to the wiring diagram
shipped with your unit (either affixed to the side jacket
or enclosed in your unit’s installation instruction
envelope). Should any original wire supplied with the
heater have to be replaced, it must be replaced with
wiring material having a temperature rating of at least
105°C.
Should any high limit wires have to be replaced, they
must be replaced with wiring material having a
temperature rating of 200°C minimum.

GMND-SVX01B-EN

Start-Up
Operation
Explanation of Controls

WARNING
Carbon Monoxide!
Never operate duct furnaces if the power venter is not
operable. Your venting system must not be blocked by
any snow, snow drifts, or any foreign matter. Inspect
your venting system to ensure adequate ventilation
exists at all times! Failure to follow these
recommendations could result in death or serious
injury due to Carbon Monoxide Poisoning (symptoms
include grogginess, lethargy, inappropriate tiredness, or
flu-like symptoms).
1. Each Separated Combustion Duct Furnace comes
equipped with a power vent system that consists of a
power venter motor and blower, pressure switch, and
sealed flue collector (Figure 20, p. 32).

NOTICE:
Additional Devices!
The addition of external draft hoods or power venters is
not permitted. Addition of such devices could cause
severe unit malfunction or failure!
2. The power venter motor is energized by the room
thermostat when a demand for heat is sensed. The
pressure switch measures the pressure differential
between the air inlet and exhaust vent systems. If the
differential is correct, the indirect spark ignition system
is energized.
3. The indirect spark ignition system consists of an
ignition module, a dual combination valve, and a
spark-ignited pilot burner. When the pressure switch is
closed, the pilot valve opens as a spark is generated to
light the pilot. When the flame is sensed by the flame
sensing circuit, the spark ceases, and the main gas
valve is opened to supply gas to the main burners.
Once the thermostat has been satisfied, the vent
system and gas valve are simultaneously deenergized, stopping all gas flow to the unit.

4. The high limit switch interrupts the flow of electric
current to the main gas valve if the duct furnace
becomes overheated.
5. The optional fan switch delays the operation of the fan
is delayed for approximately 45 seconds once the
thermostat is closed, and continues fan operation for
approximately 65 seconds after the thermostat opens.
Note: The start-up fan delay must not exceed 90
seconds from a cold start.
6. The wall thermostat, supplied optionally, is a
temperature sensitive switch that operates the vent
and ignition systems to control the temperature of the
space being heated.
Note: The thermostat must be mounted on a vertical,
vibration-free surface, free from air currents,
and in accordance with the furnished
instructions.

Initial Lighting
1. Open the manual gas valve, in the gas supply line to the
duct furnace. Loosen the union in the gas supply line to
purge it of air. Tighten the union and check for leaks.

WARNING
Hazard of Explosion!
Never use an open flame to detect gas leaks. Explosive
conditions may occur. Use a leak test solution or other
approved methods for leak testing. Before attempting
to light or relight the pilot, wait 5 minutes to allow gas
which may have accumulated in the burner
compartment to escape. Failure to follow
recommended safe leak test procedures or pilot
lighting/relighting instructions could result in death or
serious injury or equipment or property-only-damage.
2. Turn on the electrical power. The duct furnace should
now be under the control of the thermostat. Set the
thermostat to its highest setting; the power venter
motor should start and burner ignition occur. Turn the
thermostat to its lowest setting. The burners and
power venter should stop operating immediately.
Reset the thermostat to the desired operational setting.

Shut-Down
1. Turn the valve selector knob to the OFF position.
2. Turn off the electricity.
3. To relight, follow the instructions in “Initial Lighting,”
p. 26 (preceding section).

GMND-SVX01B-EN

Start-Up
Figure 18. Burner components (intermittent pilot ignition)
Burner Drawer Common Parts:
1.
2.
3.
4.
5.
6.
7.

Main Burners
Burner Manifold
Air Shutters
Burner Springs
Main Burner Orifice
Transformer
Pilot Tubing

Controls:
8A. Main Gas Valve (Honeywell)
8B. Main Gas Valve (White-Rodgers)
9. Honeywell Ignitor
10. Honeywell Pilot Burner
11. Honeywell Pilot Orifice
12. Honeywell Electrode/Sensor Lead
13. Hi Limit Switch (Located on Rear Header
Plate of Heat Exchanger, Air Inlet Side)

8A
O
F
F

8B
O
N

10
11
9

eywe

S860
CON
0M
TINU
OU
10
90 SE 0% SH S RE-TR
UTO
Y
C. TR
IAL FO FF IP
R IG
NITIO

24V
(GND
)
24V

Hon

TH-W
(OPT.)

(BURNER)

MV/PV

M
V
1

NING

P
V
GND

WAR

SPARK

GMND-SVX01B-EN

Start-Up
Gas Input Rate

pressure must be regulated to attain this manifold
operating pressure.

NOTICE:

Table 7.

Main burner orifice schedule(a)

Overfiring!

Type of Gas Natural

Never overfire the duct furnace, as this could cause
unsatisfactory operation, or shorten the life of the
heater.

Heating
Value

1075 BTU/ft3
(40.1 MJ/m3)

2500 BTU/ft3
(93.1 MJ/m3)

Check the gas input rate as follows:
1. Turn off all gas appliances that utilize gas through the
same gas meter as the unit heater.
2. Turn gas on to the unit heater.
3. Using the gas meter, clock the time that it takes to burn
one cubic foot of gas (Heating Value).

Input in
1000
Manifold
BTU(a) Pressure
100

125

150

175

4. Insert the time, in seconds, into the formula below:
Input Rate =

Heating Value (Btu/ft3) (3600 s/hr)
Time (s/ft3)

Example: If the heating value = 1000 BTU/ft3 and the time/
ft3 = 18 s/ft3 then
Input Rate =

(1000 BTU/ft3) (3600 s/hr)
18 s/ft3

Input Rate = 200,000 BTU/hr
(Refer to “General Safety Information,” p. 7 for metric
conversions.)
Note: If the computation exceeds, or is less than 95
percent of the gas Btu/h input rating (see “Unit
Dimensions and Weights,” p. 10), adjust the gas
pressure:.

Gas Pressure Adjustments
Adjust the gas pressure as follows:
1. NATURAL GAS: Best results are obtained when the
duct furnace is operating at its full input rating with the
manifold pressure of 3.5 inches wc (0.9 kPa).
Adjustment of the pressure regulator is not normally
necessary since it is preset at the factory.
However, field adjustment may be made as follows:
a. Attach manometer at pressure tap plug below the
control outlet.
b. Remove the regulator adjustment screw cap,
located on the combination gas valve.
c. With a small screwdriver, rotate the adjustment
screw clockwise to increase pressure.
d. Replace regulator adjustment screw cap.
2. PROPANE GAS: An exact manifold pressure of
10.0 inches wc (2.5 kPa) must be maintained for proper
operation of the duct furnace. If the unit is equipped
with a pressure regulator on the combination gas
valve, follow Step a through Step d (above). If the unit
is not so equipped, the propane gas supply system
28

200

225

250

300

350

400

Propane

No. of
Burner
3.5” wc (0.9 kPA) 10.5” wc (2.6 kPA) Orifices

ft3/hr

Orifice Drill

ft3/hr

120

Orifice Drill

ft3/hr

140

Orifice Drill

ft3/hr

163

Orifice Drill

ft3/hr

186

Orifice Drill

ft3/hr

210

Orifice Drill

ft3/hr

233

100

Orifice Drill

ft3/hr

280

120

Orifice Drill

ft3/hr

326

140

Orifice Drill

ft3/hr

372

160

Orifice Drill

Note: When installed in Canada, any references to deration at altitudes in
excess of 2000 feet (610 m) are to be ignored. At altitudes of 2000
to 4500 feet (610 to 1372 m), the unit heaters must be orificed to
90 percent of the normal altitude rating, and be so marked in
accordance with the CSA certification.
(a) This schedule is for units operating at normal altitudes of 2000 feet
(610 m) or less. SPECIAL ORIFICES ARE REQUIRED FOR INSTALLATIONS ABOVE 2,000 FEET (610 m).

Primary Air Shutter Adjustment
After the unit has been operating for at least 15 minutes,
adjust the primary air flow to the burners. Turn the frictionlocked, manually-rotated air shutters clockwise to close, or
counterclockwise to open.
For correct air adjustment, close the air shutter until yellow
tips in the flame appear. Then open the air shutter to the
point just beyond the position where yellow tipping
disappears. Refer to Figure 19.
Note: There may be momentary and spasmodic orange
flashes in the flame. This is caused by the burning
of airborne dust particles, and should not be
confused with the yellow tipping, which is a stable
or permanent situation when there is insufficient
primary air.

GMND-SVX01B-EN

Start-Up
Figure 19. Main burner flames

NORMAL
(HARD FLAME)

YELLOW TIPPING
(MARGINAL)

LIFTING
(TOO MUCH AIR)

YELLOW FLAME
(TOO LITTLE AIR)

Pilot Adjustment
1. Remove the pilot adjustment cap.
2. Adjust the pilot screw to provide a properly sized
flame.
3. A proper pilot flame is a soft steady flame that
envelops 3/8- to 1/2-inch (9.5 to 12.7 mm) of the flame
sensor.
4. Replace the pilot adjustment cap.

Manifold Pressure Adjustment
If the manifold pressure requires adjustment, remove the
cap from the pressure regulator and turn the adjustment
screw clockwise to increase the pressure, or
counterclockwise to decrease the pressure. The adjusted
manifold pressure should not vary more than 10 percent
from the pressures specified in Table 7, p. 28.

GMND-SVX01B-EN

Start-Up

Gas Equipment Start-Up
Customer _____________________________________________

Job Name & Number _________________________

Pre-Inspection Information with Power and Gas Off
Type of Equip:

Duct Furnace

Serial Number: _________________________

Model Number: _____________________________

Name Plate Voltage: ____________________

Name Plate Amperage: ______________________

Type of Gas:

Tank Capacity:

Natural

_______ lb

Rating:

_______ kg

_______ Btu @ ____ °F
________ kW @ ____ °C



Are all panels, doors, vent caps in place?



Has the unit suffered any external damage?



Does the gas piping and electric wiring appear to be installed in a professional manner?



Has the gas and electric been inspected by the local authority having jurisdiction?



Is the gas supply properly sized for the equipment?



Were the installation instructions followed when the equipment was installed?



Have all field installed controls been installed?



Do you understand all the controls on this equipment? If not, contact your wholesaler or rep. (DO NOT START
this equipment unless you fully understand the controls.)

Damage ______________________________

GENERAL
With power and gas off.

GAS HEATING
With power and gas on.



Make certain all packing has been removed.



Inlet gas pressure. ____ in. wc or ____ kPa



Tighten all electrical terminals and connections.



Pilot and main burner ignition.



Check all fans and blowers for free movement.



Manifold gas pressure. ____ in. wc or ____ kPa



Check all controls for proper settings.



Cycle firestat and/or freezestat.



Check all set screws on blowers and bearings.



Check electronic modulation. Set at: __________



Check belt tightness.



Cycle and check all other controls not listed.



Check operation of remote panel.

BLOWER



Entering air temp. _____ °F or ____ °C

With power on and gas off.



Discharge air temp. (high fire) ____ °F. or ____ °C



External static pressure _________ in. wc



Check voltage L1 _____ L2 _____ L3 _____



Check rotation of main .



Check motor amps L1 _____ L2 _____ L3 _____



Blower RPM _____________



Check air filters. (Record quantity & size.)

Remarks: _____________________________________________________________________________________________________
_______________________________________________________________________________________________________________
_______________________________________________________________________________________________________________

GMND-SVX01B-EN

Maintenance
WARNING
Hazardous Service Procedures!
The maintenance and troubleshooting procedures
recommended in this section of the manual could
result in exposure to electrical, mechanical or other
potential safety hazards. Always refer to the safety
warnings provided throughout this manual concerning
these procedures. When possible, disconnect all
electrical power including remote disconnect and
discharge all energy storing devices such as capacitors
before servicing. Follow proper lockout/tagout
procedures to ensure the power can not be
inadvertently energized. When necessary to work with
live electrical components, have a qualified licensed
electrician or other individual who has been trained in
handling live electrical components perform these
tasks. Failure to follow all of the recommended safety
warnings provided, could result in death or serious
injury.

Periodic Service
All Maintenance/Service information should be recorded
accordingly on the inspection sheet provided in this
manual (see “Gas Equipment Start-Up,” p. 30).
Note: The heater and vent system should be checked
once a year by a qualified technician.

Gas tightness of the safety shut-off valves
must be checked on at least an annual basis.

WARNING
Hazard of Explosion!
Never use an open flame to detect gas leaks. Explosive
conditions may occur. Use a leak test solution or other
approved methods for leak testing. Failure to follow
recommended safe leak test procedures could result in
death or serious injury or equipment or property-onlydamage.
To check gas tightness of the safety shut-off valves, turn off
the manual valve upstream of the appliance combination
control. Remove the 1/8-inch pipe plug on the inlet side of
the combination control and connect a manometer to that
tapping. Turn the manual valve on to apply pressure to the
combination control. Note the pressure reading on the
GMND-SVX01B-EN

manometer, then turn the valve off. A loss of pressure
indicates a leak. If a leak is detected, use a soap solution to
check all threaded connections. If no leak is found,
combination control is faulty and must be replaced before
putting appliance back in service.
Should maintenance be required, perform the following
inspection and service routine:
1. Inspect the area near the unit to be sure that there is no
combustible material located within the minimum
clearance requirements listed in this manual (see
Table 3, p. 12).

WARNING
Combustible Materials!
Maintain proper clearance between the unit heat
exchanger, vent surfaces and combustible materials.
Refer to unit nameplate and installation instructions for
proper clearances. Improper clearances could result in a
fire hazard. Failure to maintain proper clearances could
result in death or serious injury or property damage.
2. Turn off the manual gas valve and electrical power to
the gas duct furnace.
3. To clean or replace the main burners, remove the
bottom panel and compress the spring by moving the
burner toward the manifold. Slide the opposite end of
the burner downward from the locating slot while
retaining spring is still compressed. Pull the burners
away from the heater.
4. With the burners removed, wire brush the inside
surfaces of the heat exchanger.
5. Remove any dirt, dust, or other foreign matter from the
burners using a wire brush and/or compressed air.
Ensure that all parts are unobstructed. Inspect and
clean pilot burner if necessary.
6. Reassemble the gas duct furnace by replacing all parts
in reverse order.
7.

Complete the appropriate unit start-up procedure as
given in “Operation,” p. 26 (see unit lighting instruction
plate and the unit nameplate).

8. Check the burner adjustment (see “Primary Air Shutter
Adjustment,” p. 28).
9. Check all gas control valves and pipe connections for
leaks.
10. Check the operation of the automatic gas valve by
lowering the setting of the thermostat, stopping the
operation of the gas duct furnace. The gas valve should
close tightly, completely extinguishing the flame on
the main burners.
11. Inspect and service the blower section of the system.
Check and test the operational functions of all safety
devices supplied with your unit.

Maintenance
Figure 20. Power venter assembly

Ref. No.

Description

Ref. No.

Description

Blower Housing Assembly

Snap Bushing

Speed Nut

Relay (Motor)

Motor

Draftor Stack Assembly

Washer, Plain

Tubing (Aluminum) Formation

Plate Adapter

Male Connector

Blower Wheel (see Note 1)

Locknut

Mounting Bracket (Pressure Switch)

Hole Plug

Mounting Bracket (Junction Box)

Pressure Switch Cover

Screw, S.T.

Drill Screw

Screw, Machine (L = 3/4”)

Junction Box Base

Nut, Keps (Ext. Lock Washer)

Purge Relay

Air Pressure Switch

Drill Screw

Junction Box Cover

Notes:
1. For item No. 6, use counter-clockwise rotation.
2. DO NOT OVERTIGHTEN CELCON NUT! HAND TIGHTEN ONLY! DO NOT USE TOOLS! Approximate 1/3 turn maximum or 8 inch pounds is sufficient from
the point where the tube does not slip in or out.
3. Flue Sizes:
100/175 units: 4” dia. flue outlet Reducer required—to be supplied by installer.
200/250 units: 5” dia. flue outlet (no adapter required).
300/400 units: 6” dia. flue outlet Increaser required—to be supplied by manufacturer.

GMND-SVX01B-EN

Maintenance

Installation Instructions for Field
Replacement of Power Venter Motor
Important:

This replacement must be performed only
by a qualified technician.

Note: All hardware (screws, nuts, washers) that will be
removed from the unit will be reused for this motor
replacement. DO NOT LOSE ANY OF THESE
PARTS.

Figure 21. Identification of parts
Ref. No.

Tools and Parts Needed
Wire Stripper and Crimper; Slotted Head and #2 Phillips
Head Screwdriver; 3/8-in. Wrench; 1/8-in. Allen Wrench
(long handle); marker; (1) 1/4-in. push on terminal for Wire.
Remove the cover from the Relay Junction Box (Item 1)
by removing two screws (Item 2) top and bottom.
Disconnect both wires from the motor lead ends. One
is connected to terminal #4 on the venter relay, and the
other is connected with a wire nut to a black wire.

•

Remove the sensing tube (Item 3) from the Pressure
Switch/Mounting Bracket (Item 3) at motor end only.
Separated Combustion Units: Remove both tubes at
motor end only—note location.

•

Mark locations of the Relay Junction Box and Pressure
Switch Mounting Brackets along with the Motor (Item
10) mounts on the Mounting Adapter Plate (Item 4)—
using a marker.

•

Remove nut (Item 5) that secures the Motor Support
Shipping Bracket (Item 6) to the Mounting Adapter

GMND-SVX01B-EN

Relay Junction Box/Mounting
Bracket Assembly

#8 Drill Screws (2 required)

Pressure/Mounting Bracket
Assembly

Mounting Plate Adapter

Keps Nut w/External Tooth
Lockwasher (4 required)

Motor Support Shipping Bracket

Phillips Head Screws (3 required)

Power Venter Blower Housing

Blower Wheel

Motor

Space Washers (3 required)

Machine Screw (3 required)

Sensing Tube

Set Screw

Plate. Pull this bracket away from the Motor Mounting
Adapter Plate.
•

Remove three phillips head screws (Item 7) on the
Motor mounting Adapter Plate. Remove the Motor/
Blower Wheel/Adapter Plate assembly from the Power
Venter Blower Housing (Item 8).

•

Remove the Blower Wheel (Item 9) from the motor
shaft by removing the set screw (Item 14) using a 1/8-in.
Allen Wrench.

•

Remove the three Motor Mounting Nuts (Item 5),
Space Washers (Item 11), and Screws (Item 12). Do not
lose these parts! Using caution—the motor will
disengage from the Mounting Adapter Plate, along
with the Relay Junction Box and Pressure Switch
Mounting Brackets will also disengage.

•

Reverse order to install the new Power Venter Motor.

•

TEST FIRE THE UNIT FOR A FEW CYCLES, MAKING
SURE THAT THE UNIT IS OPERATING
SATISFACTORILY.

Notes:
•

Description

Maintenance

How to Order Replacement Parts
Please send the following information to your local Parts
center; If further assistance is needed, contact the
manufacturer’s customer service department.
•

Model number

•

Serial Number

•

Part description and Number as shown in the
Replacement Parts Catalog.

GMND-SVX01B-EN

Diagnostics
Troubleshooting
WARNING
Hazardous Service Procedures!
The maintenance and troubleshooting procedures
recommended in this section of the manual could result
in exposure to electrical, mechanical or other potential
safety hazards. Always refer to the safety warnings
provided throughout this manual concerning these
procedures. When possible, disconnect all electrical
power including remote disconnect and discharge all
energy storing devices such as capacitors before
servicing. Follow proper lockout/tagout procedures to
ensure the power can not be inadvertently energized.
When necessary to work with live electrical
components, have a qualified licensed electrician or
other individual who has been trained in handling live
electrical components perform these tasks. Failure to
follow all of the recommended safety warnings
provided, could result in death or serious injury.
Table 8.

Troubleshooting guide

Symptoms

Possible Cause(s)

Corrective Action

Pressure regulator set too high.

Reset manifold pressure. Refer to “Operation,” p. 26.

Defective regulator.

Replace regulator section of combination gas valve or
complete valve.

Burner orifice too large.

Check with local gas supplier for proper orifice size and
replace. Refer to “Operation,” p. 26.

Flame lifting from burner ports.

Flame pops back.

Noisy flame.

D. Yellow tip flame (some yellow
tipping on propane gas is
permissible).

Floating flame.

GMND-SVX01B-EN

Excessive primary air.

Close air shutter. Refer to “Operation,” p. 26.

Burner orifice too small.

Check with local gas supplier for proper orifice size and
replace. Refer to “Operation,” p. 26.

Too much primary air.

Close air shutter.

Noisy pilot.

Reduce pilot gas. Refer to “Operation,” p. 26.

Irregular orifice causing whistle or
resonance.

Replace orifice.

Excessive gas input.

Reset manifold pressure. Refer to “Operation,” p. 26;
Replace regulator section of combination gas valve or
complete valve; or check with local gas supplier for proper
orifice size and replace. Refer to “Operation,” p. 26.

Insufficient primary air.

Open air shutters. Refer to “Operation,” p. 26.

Clogged burner ports.

Clean main burner ports.

Misaligned orifices.

Replace manifold assembly.

Clogged draft hood.

Clean draft hood.

Air shutter.

Check for dust or lint at air mixer opening and around the
air shutter.

Insufficient combustion air.

Check for obstruction in combustion air inlet cap and piping;
see “Installation: Piping,” p. 16.

Blocked venting.

Clean flue. Refer to “Installation: Piping,” p. 16.

Insufficient combustion air.

Check for obstruction in combustion air inlet cap and piping;
see “Installation: Piping,” p. 16.

Blocked heat exchanger.

Clean heater.

Air leak into combustion chamber
or draft hood.

Determine cause and repair accordingly.

Diagnostics
Table 8.

Troubleshooting guide (continued)

Symptoms

Possible Cause(s)

Corrective Action

1. Shut off gas immediately!

Inspect all gas piping and repair.

Blocked heat exchanger/venting.

Clean heat exchanger/flue.

Drafts around heater.

Eliminate drafts. Refer to “Installation: Mechanical,” p. 12.

Negative pressure in building.

See “Installation: Piping,” p. 16.

Gas Odor.

G. Delayed ignition.

H. Failure to ignite.

Blocked draft hood.

Clean draft hood.

Excessive primary air.

Close air shutter. Refer to “Operation,” p. 26.

Main burner ports clogged near
pilot.

Clean main burner ports.

Pressure regulator set too low.

Reset manifold pressure. Refer to “Operation,” p. 26.

Pilot decreases in size when main
burners come on.

Supply piping is inadequately sized. Refer to “Installation:
Piping,” p. 16.

Pilot flame too small.

Clean pilot orifice. Refer to “Operation,” p. 26.

Drafts around venter.

Eliminate drafts. Refer to “Installation: Mechanical,” p. 12.

Improper venting.

Refer to “Installation: Piping,” p. 16.

Main gas valve off.

Open all manual gas valves.

Lack of power at unit.

Replace fuse or turn on power supply.

Thermostat not calling for heat.

Turn up thermostat.

Defective limit switch.

Check limit switch with continuity tester. If open, replace
high limit switch.

Improper thermostat or
transformer wiring.

Check wiring per diagrams.
Replace gas valve.

Defective gas valve.

Defective thermostat.

Check thermostat and replace if defective.

Defective transformer.

Be sure 115 volts is supplied to the transformer primary,
then check for 24 volts at secondary terminal before
replacing.

Loose wiring.

Check and tighten all wiring connections per diagrams.

10. Defective ignition control.

10. Replace, if necessary. Also see U, V, and W symptoms.

Condensation of water vapor.

Refer to “Installation: Venting,” p. 18.

Burner won't turn off.

Poor thermostat location.

Relocate thermostat away from drafts.

Defective thermostat.

Replace thermostat.

Improper thermostat or
transformer wiring at gas valve.

Check wiring per diagrams.

Short circuit.

Check operation at valve. Check for short (such as staples
piercing thermostat wiring), and correct.

Defective or sticking gas valve.

Replace gas valve.

Excessive gas supply pressure.

Refer to “Installation: Piping,” p. 16.

Loose wiring connections at gas
valve or thermostat.

Tighten all connections.

Excessive thermostat heat
anticipator.

Adjust thermostat for longer cycles. Refer to “Installation:
Electrical,” p. 24.
Check for proper air supply across heat exchanger.

Rapid burner cycling.

Noisy power venter.

M. Pilot will not light or will not stay
lit.

Unit cycling on high limit.

Poor thermostat location.

Relocate thermostat. (Do not mount thermostat on unit).

Draft on pilot.

Eliminate drafts. Refer to “Installation: Mechanical,” p. 12.

Defective ignitor control.

Replace ignitor.

Defective high limit.

Jumper limit switch terminals 1 and 2. If burner operates
normally, replace switch.

Power venter wheel loose.

Replace or tighten.

Power venter wheel dirty.

Clean power venter wheel.

Power venter wheel rubbing
housing.

Realign power venter wheel.

Bearings are dry.

Oil bearings on power venter motor. (Refer to label on
motor.)

Main gas valve off.

Open all manual gas valves.

GMND-SVX01B-EN

Diagnostics
Table 8.

Troubleshooting guide (continued)

Symptoms

N. Power venter will not run.

O. Power venter motor turns on and
off while burners are operating.

Power venter motor will not stop.

Q. Not enough heat.

Too much heat.

Possible Cause(s)

Corrective Action

Increase size of pilot flame. Refer to “Operation,” p. 26.

Pilot adjustment screw turned too
low on combination main gas
valve.

Air in gas line.

Purge air from line.

Incorrect lighting procedure.

Follow lighting instruction label adjacent to gas valve.

Dirt in pilot orifice.

Remove pilot orifice. Clean with compressed air or solvent.
(Do not ream.)

Extremely high or low gas
pressure.

Refer to “Operation,” p. 26.

Drafts around unit.

Eliminate drafts. Refer to “Installation: Mechanical,” p. 12.

Pilot valve not opening (faulty
wiring).

Inspect and correct all wiring.

No spark (faulty wiring).

Inspect and correct ignition system wiring. See symptoms
U, V, and W.

10. Defective gas valve.

10. Replace gas valve.

Loose wiring.

Check and tighten all wiring connections per diagrams.
Thermostat wires tagged “W” and “G” must be connected
together (unless special thermostats are used; if so, see
thermostat wiring diagram, “Electrical Connections,” p. 24).

Defective motor overload
protector or defective motor.

Replace motor.

Defective power venter relay.

Check for 24V across terminals on fan relay. If 24V is
present, jumper terminals numbered 2 and 4. If motor runs,
the fan relay is defective and must be replaced. If 24V is not
present, check wiring per diagrams.

Fan relay heater element
improperly wired.

Be sure venter relay heater terminals are connected per
diagrams.

Defective venter relay switch.

Replace venter relay.

Motor protector cycling on and off.

Check motor amps against motor name plate rating, check
voltage, replace venter relay motor if defective.

Motor not properly oiled.

Refer to label on motor.

Improperly wired venter relay.

Check all wiring.

Main burners not lighting while
thermostat calls for heat.

Refer to H and N symptoms.

Defective venter relay.

Replace venter relay.

Incorrect gas input.

Refer to “Operation,” p. 26.

Heater undersized.

This is especially true when the heated space is enlarged.
Have the heat loss calculated and compare to the heater
output (80 percent of input). Your gas supplier or installer
can furnish this information. If heater is undersized, add
additional heaters.

Thermostat malfunction.

Replace thermostat.

Heater cycling on high limit.

Check air movement through heat exchanger. Check
voltage to fan motor. Clean power venter motor.

Check outside dampers if used.

Adjust dampers accordingly.

Thermostat malfunction.

Replace thermostat.

Heater runs continuously.

Check wiring per diagrams; check operation at valve. Look
for short (such as staples piercing thermostat wiring), and
correct; replace gas valve. Refer to “Operation,” p. 26.

Cold air is delivered on start up.

Fan relay heater element
improperly wired.

Be sure fan relay heater terminals are connected per
diagrams.

Cold air is delivered during heater
operation.

Incorrect manifold pressure or
input.

Refer to “Operation,” p. 26.

Voltage to unit too high.

Check motor voltage with fan running. Should be 115 volts
AC.

Air throughput too high.

Refer to “Operation,” p. 26.

GMND-SVX01B-EN

Diagnostics
Table 8.

Troubleshooting guide (continued)

Symptoms

Possible Cause(s)

U. No Spark.

Thermostat not calling for heat.

Close thermostat contacts.

No low voltage.

Check for 24V across 24V terminals of S8600.

Spark gap closed or too wide.

Set gap to 0.1.

Broken or cracked ceramic on
spark electrode.

Replace pilot assembly.

Loose S8600 connections.

Check all connections, term. PV feeds 24V to pilot valve.

Improper gas pressure.

Check pressure—pressure that is either too high or too low
may cause a problem.

Spark present but pilot does not
light.

W. Pilot lights — Main valve does not
energize.

Hi-Limit switch tripping.

Corrective Action

Is spark in pilot gas stream?

Spark should arc from electrode.

No pilot gas — do not use match to
test - presence of gas is easily
detected by the odor.

Check pilot line for kinks. Ensure there are no drafts.

Loose S8600 connections.

Check connections-term. MV feeds main valve.

Cracked or broken sensor
ceramic.

Replace pilot assembly.

Check sensor/spark lead for
continuity.

Replace if needed.

Measure 24 volts from term. MV to
term. MV/PV.

If present, replace main valve; if not, replace S8600 Igniter.

Unit is overfiring.

Manifold pressure too high; adjust. Burner orifices may be
too large: verify/replace if required.

Air flow too low.

Increase air flow; check fan size. Check for proper voltage.

Defective switch.

Replace.

GMND-SVX01B-EN

Wiring Diagrams
Figure 22. Standard wiring diagram for unit with S8600 ignition system

GMND-SVX01B-EN

Wiring Diagrams
Figure 23. Standard wiring diagram for unit with G770 ignition system

GMND-SVX01B-EN

Trane optimizes the performance of homes and buildings around the world. A business of Ingersoll Rand, the
leader in creating and sustaining safe, comfortable and energy efficient environments, Trane offers a broad
portfolio of advanced controls and HVAC systems, comprehensive building services, and parts.
For more information, visit www.Trane.com.
Trane has a policy of continuous product and product data improvement and reserves the right to change design and specifications without notice.
© 2012 Trane All rights reserved
GMND-SVX01B-EN 16 Mar 2012

We are committed to using environmentally

Supersedes GMND-SVX01A-EN (01 Mar 2010)

conscious print practices that reduce waste.

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Abstract                        :  SUBMITTAL - Installation, Operation, and Maintenance - Gas Unit Heater - Separated Combustion Indoor Gas-Fired Duct Furnace - Models GMND and GMPD
Hist model                      : GMND|GMND010|GMND012|GMND015|GMND030|GMND035|GMND040|GMPD|GMPD010|GMPD012|GMPD015|GMPD030|GMPD035|GMPD040
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Format                          : application/pdf
Creator                         : Gayle C. Edlin, Technical Writer - Senior TCS Literature
Title                           : GMND-SVX01B-EN 03/16/2012 Installation, Operation, and Maintenance - Gas Unit Heater - Separated Combustion Indoor Gas-Fired Duct Furnace - Models GMND and GMPD
Description                     : Installation, Operation, and Maintenance manual for the Separated Combustion Indoor Gas-Fired Duct Furnace.
Rights                          : © 2012 Trane  All rights reserved.
Subject                         : GMND, GMPD, gas unit heater, GUH
Tagged PDF                      : Yes
Author                          : Gayle C. Edlin
Acces Flag                      : F
Alt Order Nbr                   : 
Alt Order Nbr Type              : 
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Trane Gas Unit Heaters Installation And Maintenance Manual GMND SVX01B EN 03/16/2012 Installation, Operation, Heater Separated Combustion Indoor Fired Duc

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