Sterling NATURAL INDOOR GAS-FIRED DUCT FURNACE, POWER VENTED INDOOR GAS-FIRED DUCT FURNACE Installation And Service Manual

INSTALLATION AND SERVICE MANUAL

INDOOR GAS-FIRED DUCT FURNACE

(NATURAL OR POWER VENTED)

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 THE POINT OF
INSTALLATION. RECORD THE UNIT MODEL AND SERIAL No.(s) IN THE SPACE PROVIDED. RETAIN FOR FUTURE
REFERENCE.

Model No. Serial No.

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.

FOR YOUR SAFETY

If you smell gas:

1. Open windows.

2. Don't touch electrical switches.

3. Extinguish any open flame.

4. Immediately contact your gas supplier.

(S) DISM-15

J30-05373

Improper installation, adjustment, alteration, service, or maintenance can
cause property damage, injury, or death. Read the installation, operating, and
maintenance instruction thoroughly before installing or servicing this equipment.

APPROVED FOR USE IN CALIFORNIA WHEN EQUIPPED WITH SPARK IGNITION

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

Installer Please Note: This equipment has been test fired and inspected. It has been

shipped free from defects from our factory. However, 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 problem 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.

12/05

INSTALLER'S RESPONSIBILITY

HVAC PRODUCTS

260 NORTH ELM ST., WESTFIELD, MA 01085

TEL: [phone] FAX: [phone]

www.sterlinghvac.com

MODELS: QV (E) (D,S) (100, 125, 150, 200, 225,

250, 300, 350, 400) (S)

Look in direction of air flow to determine if your unit is right or left hand
accessible. Models QVS/QVES are available with standard right hand
access to service the burner drawer. Left hand is optional.

MODEL TYPE DESIGNATION

Figure 1 = Natural Vented (Standard) Duct Furnace (Bottom Access, Standing Pilot) (Optional Intermittent Pilot)
Figure 2 = Natural Vented Side Service Duct Furnace (Side Access, Standing Pilot) (Optional Intermittent Pilot)
Figure 3 = Power Vented Duct Furnace (Bottom Access, Rear Vent Position, Spark Ignition)
Figure 4 = Side Service Power Vented Duct Furnace (Side Access, Rear Vent Position, Spark Ignition)

TABLE OF CONTENTS

GENERAL SAFETY INFORMATION ..............................................................................................................1, 2, 3

DUCT FURNACES (NATURAL AND POWER VENTED)

SPECIFICATIONS .................................................................................................................................. 4, 5

PERFORMANCE DATA .............................................................................................................................. 6

INSTALLATION

Location, Clearances ................................................................................................................. 7, 8

Ductwork, Air Flow, Ventilation, Bypass .........................................................................................8

Suspension .................................................................................................................................... 9

Electrical Connections .................................................................................................................. 10

Venting .............................................................................................................................11 thru 16

Gas Piping .................................................................................................................................... 17

Pipe Installation ............................................................................................................................ 18

OPERATION

Natural Vented Units with Standing Pilot ............................................................................... 19, 20

Natural Vented Units with Optional Intermittent Pilot ............................................................. 21, 23

Power Vented Units with Intermittent Pilot .............................................................................22, 23

Adjustments ........................................................................................................................... 24, 25

Orifice Sizing ................................................................................................................................24

MAINTENANCE ........................................................................................................................................25

COMPONENT PARTS .................................................................................................................. 26, 27, 28

TROUBLESHOOTING CHART ...........................................................................................................29, 30, 31, 32

REPLACEMENT PARTS....................................................................................................................................... 33

WARRANTY .......................................................................................................................................................... 33

START-UP/INSPECTION SHEET .........................................................................................................................35

GENERAL SAFETY INFORMATION

The duct furnace design is certified by CSA International
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 the design was certified. In addition,
the duct furnace may be installed on the downstream side
of a cooling unit, without need of a bypass duct.

If the unit is to be installed at an altitude exceeding 2,000
feet (610m) above sea level, derate the input by 4% for
each 1,000 foot (305m) rise above sea level. Special
orifices are required for installations above 2,000 feet
(610m).

When units are installed in Canada, any reference to
derations at altitudes in excess of 2000 feet (610m) are to
be ignored. At altitudes of 2000 to 4500 feet (610 to
1372m), the units must be orificed to 90% of the normal
altitude rating, and be so marked in accordance with the
CSA certification.

The following terms are used throughout this manual, in
addition to CSA requirements, to bring attention to the
presence of potential hazards or to important information
concerning the product:

Indicates an imminently hazardous
situation which, if not avoided, will result in death,
serious injury or substantial property damage.

Indicates an imminently hazardous
situation which, if not avoided, could result in
death, serious injury or substantial property
damage.

Indicates an imminently hazardous
situation which, if not avoided, may result in minor
injury or property damage.

NOTICE: Used to notify of special instructions on
installation, operation or maintenance which are
important to equipment but not related to personal
injury hazards.

2

GENERAL SAFETY INFORMATION

Failure to comply with the general
safety information may result in extensive
property damage, severe personal injury or death.

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

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 CSA Information Services, 1-800-463-6727. 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 Appliances and Equipment" or CGA-B149.8
“Installation Codes for Propane Gas Burning Appliances
and Equipment”. These indoor duct furnaces have been
designed and certified to comply with CGA 2.6. Also
see sections on installation in AIRCRAFT HANGARS
and PUBLIC GARAGES.

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

Disconnect all power and gas
supplies before installing or servicing the heater.
If the power disconnect is out of sight, lock it in
the open position and tag it to prevent unexpected
application of power. Failure to do so could result
in fatal electric shock, or severe personal injury.

Insure that all power sources conform
to the requirements of the unit heater or damage to
the unit will result!

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 Electric
Code ANSI/NFPA No. 70. All gas connections should be
made and leak-tested by a suitably qualified individual,
per instructions in this manual.

Also follow procedures listed on the “Gas Equipment
Start-up” sheet located in this manual.

Use only the fuel for which the heater 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.

Do not attempt to convert the
heater for use with a fuel other than the one
intended. Such conversion is dangerous, and
could create unsafe conditions that result in death,
serious personal injury or property damage.

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

Do not depend upon a thermostat
or other switch as sole means of disconnecting
power when installing or servicing heater. Always
disconnect power at main circuit breaker as
described above. Failure to do so could result in
fatal electric shock.

Special attention must be given to any grounding
information pertaining to this heater. To prevent the risk of
electrocution, the heater must be securely and adequately
grounded. This should be accomplished by connecting a
grounded conductor between the service panel and the
heater. To ensure a proper ground, the grounding means
must be tested by a qualified electrician.

Do not insert fingers or foreign objects into the heater 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 heater 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.

In cases in which property damage may result from
malfunction of the heater, a backup system or a
temperature sensitive alarm should be used.

The open end of piping systems being
purged shall not discharge into areas where there are
sources of ignition or into confined spaces UNLESS
precautions are taken as follows: (1) By ventilation of
the space, (2) control of purging rate, (3) elimination
of all hazardous conditions. All precautions must be
taken to perform this operation in a safe manner!

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 gallon = 3.785 L
1 pound = 0.453 kg
1 psig = 6.894 kPa
1 cubic foot = 0.028 m

1000 Btu per hour = 0.293 kW
1 inch water column = 0.249 kPa
1000 Btu/Cu. Ft. = 37.5 MJ/m

3

liter/second = CFM x 0.472
meter/second = FPM ÷ 196.8

3

3

SPECIFICATIONS

Figure 1 - Standard Duct Furnace (Natural Vent) — Bottom Service Access

Table 1 - Natural Vent Duct Furnace

UNIT A B C F S GAS INLET WEIGHT
SIZE in. in. in. in. in. in. lb.

(mm) (mm) (mm) (mm) (mm) NAT. LP (kg)

100 17-7/8 15-1/2 17-1/8 23-7/8 6 RV 1/2 1/2 162

(454) (394) (435) (606) (152) RV (73)

125 20-5/8 18-1/4 19-7/8 26-5/8 6 RV 1/2 1/2 175

(524) (464) (505) (676) (152) RV (79)

150 20-5/8 18-1/4 19-7/8 26-5/8 7 RH 1/2 1/2 186

(524) (464) (505) (676) (178) RH (84)

175 23-3/8 21 22-5/8 29-3/8 7 RH 1/2 1/2 205

(594) (533) (575) (746) (178) RH (93)

200 26-1/8 23-3/4 25-3/8 32-1/8 8 RH 1/2 1/2 221

(664) (603) (645) (816) (203) RH (100)

225 28-7/8 26-1/2 28-1/8 34-7/8 8 RH 3/4 1/2 OR 3/4 243

(733) (673) (714) (886) (203) RH (110)

250 31-5/8 29-1/4 30-7/8 37-5/8 8 RH 3/4 1/2 OR 3/4 252

(803) (743) (784) (956) (203) RH (114)

300 37-1/8 34-3/4 36-3/8 43-1/8 10 OVH 3/4 1/2 OR 3/4 301

(943) (883) (924) (1095) (254) OVH (137)

350 42-5/8 40-1/4 41-7/8 48-5/8 10 OVH 3/4 1/2 OR 3/4 378

(1083) (1022) (1064) (1235) (254) OVH (171)

400 48-1/8 45-3/4 47-3/8 54-1/8 12 OV▲ 3/4 1/2 OR 3/4 392

(1222) (1162) (1203) (1375) (305) OV▲ (178)

R = Round, H = Horizontal, OV = Oval, V = Vertical

Figure 2 - Side Service Access Duct Furnace (Natural Vent)

4

SPECIFICATIONS

Figure 3 - Power Vented Furnace — Bottom Service Access

Table 2 - Power Vented Duct Furnace

UNIT A B C D (Dia) F GAS INLET WEIGHT
SIZE in. in. in. in. in. in. lb.

(mm) (mm) (mm) (mm) (mm) NAT. LP (kg)

100 17-7/8 15-1/2 17-1/8 4 23-7/8 1/2 1/2 173

(454) (394) (435) (102) (606) (78)

125 20-5/8 18-1/4 19-7/8 4 25-5/8 1/2 1/2 186

(524) (464) (505) (102) (651) (84)

150 20-5/8 18-1/4 19-7/8 4 26-5/8 1/2 1/2 197

(524) (464) (505) (102) (676) (89)

175 23-3/8 21 22-5/8 4 29-3/8 1/2 1/2 216

(594) (533) (575) (102) (746) (98)

200 26-1/8 23-3/4 25-3/8 5 32-1/8 1/2 1/2 232

(664) (603) (645) (127) (816) (105)

225 28-7/8 26-1/2 28-1/8 5 34-7/8 3/4 1/2 OR 3/4 254

(733) (673) (714) (127) (886) (115)

250 31-5/8 29-1/4 30-7/8 5 37-5/8 3/4 1/2 OR 3/4 263

(803) (743) (784) (127) (956) (119)

300 37-1/8 34-3/4 36-3/8 6 43-1/8 3/4 1/2 OR 3/4 312

(943) (883) (924) (152) (1095) (142)

350 42-5/8 40-1/4 41-7/8 6 48-5/8 3/4 1/2 OR 3/4 389

(1083) (1022) (1064) (152) (1235) (176)

400 48-1/8 45-3/4 47-3/8 6 54-1/8 3/4 1/2 OR 3/4 403

(1222) (1162) (1203) (152) (1375) (183)

Figure 4 - Power Vented Duct Furnace — Side Service Access

5

PERFORMANCE DATA

Table 3

INPUT OUTPUT

(MAX) (MIN) MIN. Temp. Rise P.D. in. MAX. Temp. Rise P.D. in.
UNIT MBH MBH MBH CFM Deg. F. of Water CFM Deg. F. of Water
SIZE (kW) (kW) (kW) (cu. m/s) (Deg. C.) (kPa) (cu. m/s) (Deg. C.) (Pascals)

100 100 50 80 929 80 0.12 2469 30 0.90

(29.3) (14.6) (23.4) (0.438) (44) (0.03) (1.165) (17) (0.22)

125 125 62.5 100 1157 80 0.13 3086 30 0.80

(36.6) (18.3) (29.3) (0.546) (44) (0.03) (1.457) (17) (0.20)

150 150 75 120 1389 80 0.15 3704 30 0.75

(43.9) (22.0) (35.1) (0.656) (44) (0.04) (1.748) (17) (0.19)

175 175 87.5 140 1620 80 0.14 4321 30 0.75

(51.2) (25.6) (41.0) (0.765) (44) (0.03) (2.040) (17) (0.19)

200 200 100 160 1852 80 0.14 4938 30 0.75

(58.6) (29.3) (46.9) (0.874) (44) (0.03) (2.331) (17) (0.19)

225 225 112.5 180 2083 80 0.14 5556 30 0.75

(65.9) (32.9) (52.7) (0.983) (44) (0.03) (2.622) (17) (0.19)

250 250 125 200 2315 80 0.14 6173 30 0.80

(73.2) (36.6) (58.6) (1.093) (44) (0.03) (2.914) (17) (0.20)

300 300 150 240 2778 80 0.13 7407 30 0.90

(87.8) (43.9) (70.3) (1.311) (44) (0.03) (3.496) (17) (0.22)

350 350 175 280 3241 80 0.13 8642 30 0.90

(102.5) (51.2) (82.0) (1.530) (44) (0.03) (4.079) (17) (0.22)

400 400 200 320 3704 80 0.14 9877 30 0.90

(117.1) (58.6) (93.7) (1.748) (44) (0.03) (4.662) (17) (0.22)

Ratings are shown for unit installations at elevations between 0 and 2,000 ft. (610m).
For unit installations in U.S.A. above 2,000 ft. (610m), the unit input must be derated 4% for each 1,000 ft. (305m) above sea level;
refer to local codes, or in absence of local codes, refer to the latest edition of the National Fuel Gas Code, ANSI Standard Z223.1
(N.F.P.A. No. 54). For installations in Canada, any references to deration at altitudes in excess of 2,000 ft. (610m) are to be ignored. At
altitudes of 2,000 to 4,500 ft. (610 to 1372m), the unit must be derated 90% of the normal altitude rating, and be so marked in
accordance with the CSA certification.

TEMPERATURE RISE AND PRESSURE DROP GRAPH

6

INSTALLATION

Do not install duct furnaces in corrosive
or flammable atmospheres! Premature failure of, or
severe damage to the unit will 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 will occur!

NOTICE: Location of duct furnaces is related directly
to the selection of sizes. Basic rules are as follows:

ACCESSIBILITY: If unit is a bottom service access type

allow a minimum of 21 inches (533mm) at the bottom of
the unit to facilitate servicing the burners and pilot, or six
inches (152mm) if the unit has a side access burner
drawer. Provision should also be made to assure acces­sibility for recurrent maintenance purposes.

AIRCRAFT HANGARS: Duct furnaces must be installed
in aircraft hangars and public garages as follows: In
aircraft hangars, duct furnaces must be at least 10 feet
(3.05m) above the upper surface of wings or engine
enclosures of the highest aircraft to be stored in the
hangar and 8 feet (2.4m) above the floor in shops,
offices and other sections of the hangar where aircraft
are not stored or housed. Refer to current ANSI/NFPA
No. 409, Aircraft Hangars. 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 separated
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
(457mm) above the floor or protected by a partition not
less than 18 inches (457mm) 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.”

When the unit is equipped with an automatic gas ignition
system, the duct furnace must be installed such that the
gas ignition control system is not directly exposed to
water spray, rain or dripping water.

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 the point
where water vapor (a flue gas by product) 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 floor surface. Additional duct
furnaces should be installed if a minimum 50°F (10°C)
thermostat setting cannot be maintained.

Under no circumstances should
combustible material be located within the
clearances specified in Table 4. Failure to provide
proper clearance could result in personal injury
or equipment damage from fire.

Maintain adequate clearances around air openings into
combustion chamber:

Table 4 - Minimum Clearances

SIDES

TOP

BOTTOM*

FLUE

*21" (533 mm) is required for
accessibility on furnaces with
bottom access burner
compartments.

6" (152 mm)
6" (152 mm)
6" (152 mm)
6" (152 mm)

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

CLEARANCES

DRAFTS: Avoid installing the duct furnace in an

extremely drafty location. Strong drafts may cause pilot
outage. Units with intermittent pilot ignition may be
preferable in areas where drafts cannot be avoided.

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.

NOTICE: 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.

The duct furnace must be installed on the positive
pressure side of the air circulation blower.

7

INSTALLATION

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.

Any attempt to straighten the 90°
duct connection flanges on the duct furnaces 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.

Figures 5 and 6 illustrate recommended ductwork
designs for both the straight-through and elbowed air
inlet arrangements.

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 mechanical vibration.

AIR FLOW

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

COMBUSTION INLET AIR VENTILATION
Inlet Air From Another Room — If the duct furnace is

installed in a tightly constructed room or compartment,
provide two inlet air openings. The size of each vent
opening should be no less than one square inch (6.452
square centimeters) of free area for each 1000 Btu/hr.
(293 W) input. Each opening must not be less than 100
square inches (645 square centimeters).

Inlet Air From Outdoors — If the enclosed space is to
have inlet combustion air from the outside, the vent
opening must not be smaller than one square inch
(6.452 square centimeters) of free area for each 2500­3000 Btu/hr. (733-879 W) input. Each opening must not
be less than 100 square inches (645 square
centimeters).

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

Insure that all hardware used in
the suspension or each unit heater is more than
adequate for the job. Failure to do so may
result in extensive property damage, personal
injury or death.

Figure 5 - Recommended Design for Field

Installation of Ductwork for Straight­Through Arrangement

Figure 6 - Recommended Ductwork Design for

Elbowed Arrangement

8

SUSPENSION

The 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 will result in poor performance and/or
premature failure of the unit. Refer to Figure 7 for typical suspension arrangements.

METHODS USED TO LIFT THE UNIT HEATER ARE

MAKE CERTAIN THAT THE LIFTING

CAPABLE OF SUPPORTING THE WEIGHT OF THE

HEATER DURING INSTALLATION. FAILURE TO HEED

THIS WARNING MAY RESULT IN PROPERTY DAMAGE

OR PERSONAL INJURY.

FURNACE IS TO BE MOUNTED IS CAPABLE OF SAFELY SUPPORTING ITS

MAKE CERTAIN THAT THE STRUCTURE TO WHICH THE

WEIGHT. UNDER NO CIRCUMSTANCES MUST THE GAS LINES, VENTING

SYSTEM OR THE ELECTRICAL CONDUIT BE USED TO SUPPORT THE

HEATER OR ANY OTHER OBJECTS (I.E. LADDER, PERSON) LEAN

AGAINST THE HEATER GAS LINES, VENTING SYSTEM OR ELECTRICAL

CONDUIT FOR SUPPORT. FAILURE TO HEED THESE WARNINGS MAY

RESULT IN PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.

Figure 7

9

ELECTRICAL CONNECTIONS

HAZARDOUS VOLTAGE!

DISCONNECT ALL ELECTRIC
POWER INCLUDING REMOTE
DISCONNECTS BEFORE
SERVICING. Failure to
disconnect power before
servicing can cause severe
personal injury or death.

Standard units are shipped for use on 115 volt, 60 hertz
single phase electric power. The motor name-plate and
electrical rating on 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.

Do not use any tools (i.e. screwdriver,
pliers, etc.) across the terminals to check for power.
Use a voltmeter.

* Thermostat wires tagged “W” and “G” must be connected
together except when using a general purpose “SPDT”
24VAC relay and a standard thermostat with subbase, or
when using Honeywell T834H-1009 or T834H-1017
thermostats. Also refer to figure 8 for other wiring
connections.

Figure 8 - C1267G

THERMOSTAT HEAT ANTICIPATOR ADJUSTMENTS:

The initial heat anticipator setpoint should equal the
heater control circuit's current (amperage) draw when
the unit is firing. This current 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.

USE COPPER CONDUCTORS ONLY!

UNIT TERMINALS ARE NOT DESIGNED TO ACCEPT
OTHER TYPES OF CONDUCTORS. Failure to do so
may cause damage to the equipment.

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 for each duct furnace should be
located as close to the gas valve and controls 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.

THERMOSTAT WIRING AND LOCATION

NOTICE: 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.

Recommended Heat Anticipator Setting Ranges:

25 ft. (7.6m) 50 ft. (15.2m)

Gas Ignition Type T'stat Wiring T'stat Wiring

For Natural Vent Units:
Standing Pilot 0.68 to 0.75 A 0.73 to 0.81 A
Intermittent (Spark) 0.76 to 0.81 A 0.81 to 0.91 A

For Power Vented Units:
Intermittent (Spark) 0.85 to 0.90 A 0.90 to 1.1 A

Max. Setting

on T'stat

FAN TIME DELAY CONTROL (OPTIONAL)

Leads from time delay controls are factory wired to the
junction box (when ordered as an optional component).
The fan control is a time delay relay (approximately 45
seconds ON, 65 seconds OFF). The fan control is rated at
17 amps.

NOTICE: The start-up fan delay must not exceed 90
seconds from a cold start.

NOTICE: For all wiring connections, refer to the
wiring diagram that your unit is equipped with (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 or blocked vent (spill) switch
wires have to be replaced, they must be replaced
with wiring material having a temperature rating of
200°C minimum.

10

VENTING

ANSI now organizes vented
appliances into four categories.

Category

I

Includes non-condensing
appliances with negative vent

Venting Categories

Non

Condensing Condensing
Negative
Vent III
Pressure

Positive
Vent III IV
Pressure

pressure, like the traditional
atmospheric unit heater.

Category

II

Groups condensing appliances
with negative vent pressure.

VENTING FOR NATURAL VENTED (CATEGORY I) DUCT FURNACES

(Figures 1 and 2)

ALL DUCT FURNACES MUST BE VENTED!

All venting installations shall be in accordance with “Part
7 , Venting of Equipment of the National Fuel Gas Code,
ANSI Z223.1, or applicable provisions of local building
codes.” See below for Canadian Installations. *

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! Failure to heed these warnings
could result in Carbon Monoxide Poisoning
(symptoms include grogginess, lethargy,
inappropriate tiredness, or flu-like symptoms).

This duct furnace is equipped with a

blocked vent (spill) shutoff switch.

Before start up, push reset button on blocked vent

(spill) shutoff switch.

If the venting system becomes blocked or there is
continuous spillage, the vent shutoff switch will shut
off the duct furnace. Before resetting the switch,
check to see if the vent system is blocked; remove
any blockage.

To reset the switch (which is located in the upper
corner of the draft diverter), push the reset button
after the duct furnace has cooled down.

Category

III

Appliances are non-condensing
and operate with a positive vent
pressure.

Category

IV

Covers condensing appliances
with positive vent pressure.

NOTICE: Category II and IV do
not apply to equipment specified
within this manual.

Observe the following precautions when venting the unit:

1. Use flue pipe of the same size as the flue
connections on the gas duct furnace (See Table #1).
All heaters should be vented with a UL Listed Type B
vent; a factory built chimney or a lined brick and
mortar chimney that has been constructed in
accordance with the National Building Code.

2. Where two or more gas duct furnaces vent into a
common flue, the cross sectional area of the
common flue must be equal to the largest vent
connection, plus 50% of the area of each additional
vent connection.

3. Provide as long a vertical run of flue at the gas duct
furnace as possible. A minimum of five feet (1.52m)
of vertical flue is required. The top of the vent pipe
should extend at least two feet (.61 m) above the
highest point on the roof. Install a weather cap over
the vent opening.

4. Slope horizontal runs upward from the gas duct
furnace at least 1/4-inch per foot (21mm/m).
Horizontal runs should not exceed 75% of the vertical
height of the vent pipe, or chimney, above the flue
pipe connection, up to a maximum length of 10 feet
(3m). Horizontal portions of the venting system shall
be supported at maximum intervals of four feet
(1.22m) to prevent sagging. See Figure 9.

NOTICE: The switch will not reset hot.

Figure 9

* The following instructions apply to Canadian

installations in addition to installation and operating
instructions:

1. Installation must conform with local building codes,
or in absence of local codes, with current CGA
B149.1, Installation Codes for Natural Gas Burning
Appliances and Equipment, or CGA B149.2,
Installation Codes for Propane Gas Burning
Appliances and Equipment.

2. Any reference to U.S. standards or codes in these
instructions are to be ignored and the applicable
Canadian standards or codes applied.

11