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.
SCDFM-5
J30-05393
Unit No.
Serial No.
FOR Y OUR SAFETY
The use and storage of gasoline or other fl ammable v apors and liquids in open containers in
the vicinity of this appliance is hazardous.
FOR Y OUR SAFETY
If you smell gas:
1. Open windows.
2. Don’t touch electrical switches.
3. Extinguish any open fl ame.
4. Immediately call your gas supplier.
Improper installation, adjustment, alteration, service or maintenance can
cause property damage, injury or death. Read the installation, operating and
maintenance instructions thoroughly before installing or servicing this equipment.
APPROVED FOR USE IN CALIFORNIA
Install, operate and maintain unit in accordance with 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.
03/13
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.
260 NORTH ELM ST., WESTFIELD, MA 01085
TEL: (413) 568-9571 FAX: (413) 562-8437
www.mestek.com
TABLE OF CONTENTS
GENERAL SAFETY INFORMATION SEPARATED COMBUSTION DUCT FURNACE ...................................1,2,3
UNIT NUMBER DESCRIPTION .............................................................................................................................30
The duct furnace design is certifi ed 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 certifi ed. 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 altitudes exceeding 2,000
feet (610m) above sea level, derate the input by 4% for
each 1,000 feet (305m) rise above sea level. Special
orifi ces are required for installations above 2,000 feet.
When units are installed in Canada, any reference to
derations at altitudes in excess of 2,000 f eet (610m) are
to be ignored. At altitudes of 2,000 to 4,500 feet (610 to
1372m), the units must be orifi ced for 90% of normal
altitude rating, and be so marked in accordance with ETL
certifi cation.
The following terms are used throughout this manual, in
addition to the ETL 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 av oided, 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.
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 fi tter when installed
within the Commonwealth of Massachusetts.
Installation must be 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
ANSI/NFPA No. 409, and in public garages when
installed in accordance with NFPA No. 88A and NFPA
No. 88B.
If installed in Canada, the installation must conform with
local building codes, or in the absence of local building
codes, with CSA-B149.1 “Installation Codes for Natural
Gas Burning Appliances and Equipment” or CSA-B149.2
“Installation Codes for Propane Gas Burning Appliances
and Equipment. ” These duct furnaces have been designed
and certifi ed to comply with CSA 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!
Never service any component
without fi rst disconnecting all electrical and gas
supplies to the unit, or severe per sonal injury or
death may occur!
Ensure that all power sources conform
to the requirements of the duct furnace, 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 qualifi ed 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 qualifi ed 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 duct furnace is designed
(see rating plate). Using LP gas in a heater that requires
natural gas, of vice versa, will create risk of gas leaks,
carbon monoxide poisoning, and explosion.
Do not attempt to convert furnace
for use with a fuel other than the one intended.
Such conversion is dangerous, as it will create
the risks previously listed.
Make certain that the power source conforms to the
electrical requirements of the furnace.
Do not depend upon a thermostat
or other switch as sole means of disconnecting
power when installing or servicing duct furnace.
Always disconnect power at main cir cuit breaker
as described above. Failure to do so could result
in electrical shock.
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 ground conductor between the service
panel and the furnace. To ensure a proper ground, the
grounding means must be tested by a qualifi ed electrician.
Do not insert fi ngers or foreign objects into furnace or its
air moving device. Do not b lock or tamper with the heater
in any manner while in operation, or just after it has been
turned off, as some parts maybe 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 fl ammable, e xplosiv e, chemical-laden,
or wet atmospheres.
In cases in which property damage may result from
malfunction of the furnace, a back-up system or
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 confi ned spaces
UNLESS precautions are taken as follows: (1) by
ventilation of the space, (2) control of the purging
rate, (3) elimination of all hazardous conditions. All
precautions must be taken to perform this operation
in a safe manner!
Unless otherwise specifi ed, 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 = 0.453kg
1 psig = 6.894 kPa
1 cubic foot = 0.028m
1000 BTU/cu. ft. = 37.5 MJ/m
1000 BTU per hour = 0.293 kW
1 inch water column = 0.249 kPa
liter/second = CFM x 0.472
meter/second = FPM ÷ 196.8
3
3
3
SPECIFICATIONS
Table 1
A B C D (Dia)*† Gas Inlet Weight
Unit inches inches inches inches inches lb.
Size (mm) (mm) (mm) (mm) Nat LP (kg)
Ratings are shown for elevations up to 2,000 feet (610M) above sea level. Above 2,000 feet (610M), input must be derated 4% for
each 1,000 feet (305M) above sea level. When units are installed in Canada, any reference to derations at altitudes in excess of 2,000
feet (610M) are to be ignored. At altitudes of 2,000 to 4,500 feet (610 to 1372M), the units must be orificed to 90% of the normal
altitude rating, and be so marked in accordance with the ETL certifi cation.
TEMPERATURE RISE AND PRESSURE DROP-GRAPH #1
Pa
°C°F
5
CLEARANCES
Under no circumstances should
combustible material be located within the
clearances specifi ed in T ab le 3. Failure to pr ovide
proper clearance could result in personal injury
or equipment damage from fi re .
Maintain adequate clearances around air openings into
the combustion chamber:
* When clearances required for accessibility are greater
than the minimum required safety clearances, the
accessibility clearances take precedence.
INSTALLATION
NOTICE: Furnace sizing should be based on heat loss
calculations where the furnace output equals or
exceeds heat loss.
Do not install duct furnaces in a
corrosive or flammable atmosphere! Premature
failure of, or severe damage to the unit will result!
Duct furnaces must not be installed in
locations where air for combustion would contain
chlorinated, halogenated, or acidic vapors. If located
in such an envir onment, premature failure of the unit
will occur!
ACCESSIBILITY: The Separated Combustion Duct
Furnace is a bottom service access type. Allow a minimum
of 25 inches (635mm) at the bottom of the unit to facilitate
servicing the burners and pilot. Provision should be made
to assure accessibility for recurrent maintenance
purposes.
AIRCRAFT HANGARS: Separated Combustion Duct
Furnaces must be installed in aircraft hangars as follows:
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 (2.44m)
above the fl oor in shops, offi ces, 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 separated
from repair areas as specifi ed in the latest edition of NFP A
88B, Repair Garages.
NOTICE: Increasing the clearance distances may be
necessary if there is a possibility of distortion or
discoloration of adjacent materials.
Atmospheres containing commercial solvents or
chlorinated hydrocarbons will produce corrosive acids
when coming in contact with the fl ames. This will g reatly
reduce the life of the 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 Separated Combustion
Duct Furnace must be installed on the positive
pressure side of the air circulation blower.
In parking structures, duct furnaces must be installed so
that the burner fl ames are located a minimum of 18 inches
(457mm) above the fl oor or protected by a partion 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 CSA B149 “Installation Codes for Gas
Burning Appliances and Equipment.”
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 fl ue
gases are cooled inside the heat exchanger to the point
where water condenses onto the heat exchanger walls . The
result is a mildly corrosive acid which 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
of 50°F (10°C) thermostat setting cannot be maintained.
DUCTWORK: Properly designed and installed ductwork,
providing a uniformly distributed fl ow of air across the
surfaces of the heat exchanger , is essential to satisfactory
unit performance and life of the equipment.
All duct fl anges/seams must be sealed to prevent air leaks.
Sealant/tape must be suitable for temper atures of 250°F
(121°C) minimum.
Any attempt to straighten the 90°
duct connection fl anges on the duct furnace will
affect the operation of the furnace and void the
warranty.
6
INSTALLATION (Continued)
If uniform air distribution is not obtained, install additional
baffl es and/or turning vanes in the ductwork.
Access panels large enough to observe smoke and
refl ected light, and to detect the presence of leaks in the
heating equipment, are required both upstream and
downstream from the gas duct furnace. 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.
Figures 2 & 3 illustrate recommended ductwork designs
for both the straight-through and elbowed air inlet
arrangements.
AIR FLOW: The installation is to be adjusted to obtain an
air throughput within the range specifi ed on the appliance
rating plate.
Figure 2 - Recommended Design for Field Installation of Ductwork for
Straight-through Arrangement
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.
SUSPENSION: Refer to Figure 4 f or typical suspension
arrangements.
The Separated Combustion Duct
Furnace must be hung level from side to side, and
from 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 4 for typical suspension
arrangements. DO NO T mount duct furnaces in series
(one in front of another).
NOTICE: When mounting duct furnaces side by side,
units must have opposite side gas connections
(determined by Digit #6 - Furnace Type in the unit
number). Minimum safety clearances must also be
maintained; see Table 3. When service/accessibility
clearances are greater than minimum safety
clearances, service/accessibility clearances take
precedence. See “Accessibility” section under
“Installation”.
Figure 3 - Recommended Ductwork Design
for Elbowed Arrangement
Ensure that all hardware used in
the suspension or for duct furnace is more than
adequate for the job. Failure to do so may result
in extensive property damage, severe personal
injury or death!
7
INSTALLATION (Continued)
3/8-16 Treaded
Suspension Rod &
Jam Nut By Installer
3/8-16 Speed Grip
Nut Retainer
Outside Jacket
Panel (Duct)
D4285
Section “S-S”
Detail Showing Recommended
Method Of Suspension
(Typical)
“S”
“S”
D4284
Figure 4 - Typical Four Point Duct Suspending
Arrangement
ELECTRICAL CONNECTIONS
HAZARDOUS VOL TAGE!
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 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
Do not use any tools (i.e. screwdriver,
pliers, etc.) across the terminals to check for power.
Use a voltmeter.
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
MAKE CERTAIN THAT THE STRUCTURE TO WHICH THE FURNACE IS TO BE
MOUNTED IS CAPABLE OF SAFELY SUPPORTING ITS WEIGHT. UNDER NO
CIRCUMSTANCES MUST THE GAS LINES, THE VENTING SYSTEM OR THE
ELECTRICAL CONDUIT BE USED TO SUPPORT THE HEATER; OR SHOULD 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
INJURY OR DEATH.
RESULT IN PROPERTY DAMAGE,
PERSONAL
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 s witch 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 Electrical Code, ANSI/NFPA No. 70, or
CSA Standard C22.1 Sample wiring diagrams are shown
in Figures 6, and 7.
Table 4 - Full Load Current In Amperes
Ampere Values Apply to All Unit Capacities
Amps at 115 Volts1.9
Amps at 208 Volts1.1
Amps at 230 Volts 1.0
Amps at 460 Volts 0.5
Amps at 575 Volts 0.4
8
INSTALLATION (Continued)
THERMOSTAT WIRING AND LOCATION
NOTICE: The thermostat must be mounted on a
vertical, vibration-free surface, free fr om air currents,
and in accordance with the furnished instructions.
Mount the thermostat approximately 5 feet (1.5m) above
the fl oor, in an area where it will be exposed to a free
circulation of average temperature air. Alwa ys 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 ra ys , radiation, or
warm air currents may affect the operation of the
control.
3. Dead Areas- Areas where the air cannot circulate
freely, such as behind doors or in corners.
NOTICE: Thermostat wires tagged “W” and “G” must
be connected together except when using a general
purpose “SPDT” 24VAC relay and standard
thermostat with a subbase, or when using a
Honeywell T834H or T834N thermostat. Also refer to
Figure 5 for other wiring connections.
Figure 5 - C1267G
THERMOST A T HEA T ANTICIPAT OR ADJUSTMENTS
The initial heat anticipator setpoint should equal the
thermostat’s current amperage draw when the unit is
firing. This setpoint should be measured for the best
results. Use the recommended ranges f or a guide . If
further information is needed, consult your thermostat
manufacturer’ s instructions.
0.85 to 0.90 A 0.90 to 1.1 A Max.
setting on t'stat
9
Figure 6 - Standard Wiring Diagram for Unit with Honeywell Ignition System.
10
Figure 7 - Standard Wiring Diagram for Unit with Johnson Ignition System
11
INSTALLATION (Continued)
FAN TIME DELAY CONTROL (OPTIONAL)
Leads from the fan time delay control are f actory wired to
the junction box (when ordered as an optional
component). The fan time delay control is a time delay
relay (approximately 45 seconds ON, 65 seconds OFF).
The fan time delay control is r ated at 17 amps.
NOTICE: The start-up fan delay should not e xceed 90
seconds from a cold start.
IMPORTANT: For all wiring connections, refer to the
wiring diagram shipped with your unit (either affi xed
to the side jacket or enclosed in the installation
instructions envelope). Should any original wire
supplied with the heater have to be replaced, it m ust
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.
POWER VENT POSITION
Units are shipped from the factory set up for horizontal
venting. To convert the power venter for vertical or
opposite side venting, remove the shipping support
bracket, and follow this procedure:
1. Hold power venter motor in position.
2. Remove the three Phillips-head screws from the
motor adaptor plate.
3. Remove the three screws which connect the
power venter stack to the power venter housing.
4. Rotate the power v enter housing to the desired
position.
5. Replace screws accordingly.
NOTICE: The motor, pressure switch, and junction
box bracket MUST remain located as shipped
from the factory. Rotate only the blower housing!
If the power venter housing is to be moved to the
right horizontal position, the junction box must be
rotated 90 degrees CCW to clear the connection.
To do this, remove all wires, conduit and conduit
connector from the junction box, noting location
of wires. Move box, using holes provided. Move 7/8
inch plug from bottom of box to side. Reconnect all
wires according to the unit’s wiring diagram.
COMBUSTION AIR INLET SYSTEM PIPING
Never operate duct furnaces
without combustion air and fl ue gas piping in
place, or severe personal injury or death may
occur!
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).
1. The combustion air system installation must be in
accordance with the latest edition of National Fuel
Gas Code-NFP A 54, ANSI Z223.1 National Fuel Gas
Code. In Canada, installation must be in accordance
with CSA-B149.1 “Installation Code for Natural Gas
Burning Appliances and Equipment” or CSA-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, Figures 8 & 9.
NOTICE: The top of the cap is to be no less than 12
inches from the top of the exhaust vent cap. See
Figures 8 & 9.
3. Each duct furnace MUST have its own combustion
air system. It MUST NOT be connected to other air
intake systems.
4. Use single wall pipe constructed of 26 gauge
galvanized steel, or material of equivalent durability
and corrosion resistance for the combustion air
inlet system. For installations in Canada, use pipe
constructed from .025 inch thick aluminum or 0.018
inch thick steel.
Never use a pipe of a diameter
other than that specifi ed in Table 1, (“D” dia. fl ue
opening)! Never use PVC/ABS or other nonmetalic pipe for venting! To do so may result in
serious damage to the unit, or severe personal
injury or death!
12
INSTALLATION (Continued)
5. Long runs of single wall combustion air piping passing
through an unheated space may require insulating
if condensation becomes noticeable.
6. The combustion air system must be installed to
prevent collection of condensate. Pitch horizontal
pipes downward 1/4 inch per foot (21mm/m) toward
the inlet cap to facilitate drainage. V ertical combustion
air pipes should be arranged as depicted in Figure 9.
7. The equivalent length of the combustion air system
must not be less than 5 feet (1.5m) and must not
exceed 50 feet (15.2m). Equiv alent length is the total
length of straight sections PLUS 15 feet (4.6m) for
each 90° elbow and 5 feet (1.5m) f or each 45° elbow .
NOTICE: For optimum performance, keep the
combustion air system as straight as possible.
8. Each slip joint must be secured with at least three
corrosion resistant screws. T wo full turns of 3M #425
Aluminum Foil Tape or its equivalent must be used to
seal each joint. General Electric RTV-108, DowCorning RTV-732, or an equivalent, may be used
instead of the tape.
9. For horizontal combustion air systems longer than 5
feet (1.5m), the system must be supported from
overhead building structures at 3 f eet (1m) intervals.
EXHAUST VENTING - CATEGORY III
Never operate duct furnaces
without combustion air and fl ue gas piping in
place, or severe personal injury or death may
occur!
1. Vent system installation must be in accordance with
the latest edition of National Fuel Gas Code-NFPA
54, ANSI Z223.1 National Fuel Gas Code. In
Canada, installation must be in accordance with
CSA-B149.1 “Installation Code for Natural Gas
Burning Appliances and Equipment” or CSA-B149.2
“Installation Code for Propane Burning Appliances
and Equipment”.
2. A Breidert Type L or Fields vent cap furnished by the
customer, must be installed at the termination point
of the vent system, Figures 8 & 9.
3. Each unit MUST have its own vent system. It MUST
NOT be connected to other vent systems or to a
chimney.
4. Use UL 1738 listed single wall pipe for the vent
system. For installation in Canada, use corrosion
resistant and gas-tight, listed vent pipe conforming
with local building codes, or in the absence of local
building codes, with current CSA-B149.1, Installation
Codes for Natural Gas Burning Appliances and
Equipment or CSA-B149.2, Installation Codes
Propane Gas Burning Appliances and Equipment.
for
Never use a pipe of a diameter
other than that specifi ed in Table 1, (“D” dia. fl ue
opening)! Never use PVC/ABS or other nonmetallic pipe for venting! To do so may result in
serious damage to the unit or severe personal
injury or death!
5. Any run of single wall vent pipe passing through an
unheated space must be insulated with an insulation
suitable to 550°F.
6. The combustion and exhaust vent air systems must
be installed to prevent collection of condensate.
Pitch horizontal pipes downward 1/4 inch per foot
(21mm/m) toward the terminal caps to facilitate
drainage (see Figure 8A). Vertical vent pipes should
be arranged as depicted in Figure 8.
7. The equivalent length of the vent system must not
be less than 5 feet (1.5m) and must not exceed 50
feet (15.2m). Equivalent length is the total length of
straight sections PLUS 15 feet (4.6m) for each 90°
elbow and 5 feet (1.5m) for each 45° elbow.
8. 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 be used
to seal each joint. General Electric RTV-108, DowCorning RTV-732, or an equivalent, may be used
instead of the tape.
9. For horizontal vent systems longer than 5 feet
(1.5m), the system must be supported from
overhead building structures at 3 f eet (1m) intervals.
10. The exhaust vent system must remain at a minimum
of 6 inches (152mm) from all combustible materials.
Any part of the vent system that passes through a
combustible material must be properly insulated.
NOTICE: Increasing the clearance distance may be
necessary If there is a possibility of distortion or
discoloration of adjacent materials.
For a VERTICAL v ent pipe section that passes through a
floor or roof, an opening 4 inches (102mm) greater in
diameter is required. The opening must be insulated and
fl ashed 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 9A.
11. The top of a VER TICALLY VENTED exhaust system
must extend at least 3 feet (1m) above the roof
surface that it passes through. The point of
termination for a HORIZONTALLY VENTED exhaust
system must be at least 12 inches (305mm) from the
exterior wall that it passes through. See V ent System
T ermination Clearance Requirements in T ab le 5. See
V ent/Intake Installations in Figures 8 & 8A.
13
INSTALLATION (Continued)
Vent Systems
Termination Clearance Requirements
Minimum Clearance
Structure/Object
Door, window, or gravity vent
inlet; combustion air inlet for
other appliances
Forced air inlet within 10 feet3 feet above6 feet (1.8m)
Adjoining Building or parapet10 feet10 feet (3.04m)
Adjacent public walkways
Electric, gas meters
& regulators
Above grade level*1 feet1 feet (0.3m)
*Minimum above maximum snow depth, or per local code, whichever is
greater.
for Termination Locations
USACANADA
9 inches for 10,000
to 50,000 BTU/Hr
input; 12 inches for
input exceeding
50,000 BTU/Hr.
7 feet above
grade
4 feet horizontal
9 inches (230mm)
for 10,000 to
50,000 BTU/Hr
input; 12 inches
(305mm) for input
exceeding 50,000
BTU/Hr.
7 feet (2.1m) above
grade
3 feet (0.9m)
horizontally from
meter/regulator
asembly. 6 feet
(1.8m), any
direction, from
a gas service
regulator vent
outlet
Figure 8. Vertical Intake/Vent Installation
CAT-2764C
14
Figure 8A. Horizontal Intake/Vent Locations
Figure 9. Vertical Vent Installation
CAT-2765B
Figure 9A. Horizontal Vent Installation
CAT-2767B
CAT-2766B
15
GAS PIPING
To avoid damage or possible
personal injury, do not connect gas piping to this
unit until a supply line pressure/leak test has
been completed. Connecting the unit before
completing the pressure/leak test may damage
the gas valve and result in fi re hazard.
Do not rely on a shut-off valve to
isolate the unit while conducting gas pressure/
leak tests. These valves may not be completely
shut off, exposing the gas valve to excessive
pressure and damages.
PIPE SIZING
T o provide adequate gas pressure to the gas duct furnace,
size the gas piping as follows:
1. Find cu. ft./hr. by using the following formula:
Input
Cu. ft./hr. =
BTU/Cu. ft.
2. Refer to Table 6. Match “Length of Pipe in F eet” with
appropriate “Gas Input - Cu. Ft./Hr.” fi gure. This fi gure
can then be matched to the pipe size at the top of the
column.
Example:
It is determined that a 67 foot (20.4m) run of gas pipe is
required to connect a 200 MBTU gas duct furnace to a
1,000 BTU/cu. ft. (0.29kW) natural gas supply.
200,000 BTU/Hr
1,000 BTU/Cu. ft.
= 200 Cu. ft./hr.
Using Table 6, a 1 inch pipe is needed.
NOTICE: See General Safety Information section for
English/Metric unit conversion factors.
NOTICE: If more than one duct furnace is to be served
by the same piping arrangement, the total cu. feet/hr .
input and length of pipe must be considered.
NOTICE: If the duct furnace is to be fi red with LP
gas, consult your local LP gas dealer for pipe siz e
information.
NOTICE: Heater installation for use with propane
(bottled) gas must be made by a qualifi ed LP gas
dealer or installer. He will insure that proper joint
compounds are used for making pipe connections;
that air is purged from lines; that a thorough test is
made for leaks before operating the heater; and that
it is properly connected to the propane gas supply
system.
Before any connection is made to the existing line
supplying other gas appliances, contact the local gas
company to make sure that the existing line is of adequate
size to handle the combined load.
Table 6 - Gas Pipe Size
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 Specifi c Gravity Gas)
Nominal
1. Determine the required Cu. feet / Hr. by dividing the rated heater input by 1000. For SI / Metric measurements: Convert unit Btu. / Hr. to
kilowatts. Multiply the units input (kW) by 0.0965 to determine Cubic Meters / Hour. 2. FOR NATURAL GAS: Select the pipe size directly
from the table. 3. FOR PROPANE GAS: Multiply the Cu. feet / Hr. (Cubic Meters per Hour) value by 0.633; then use the table. 4. Refer to
the metric conversion factors listed in General Safety section for more SI unit measurements/conversions.
16
PIPE INSTALLATION
D3631C
1. Install the gas piping in accordance with applicable
local codes.
2. Check gas supply pressure. Each duct furnace must
be connected to a manifold pressure and a gas
supply capable of supplying its full rated capacity as
specifi ed in Table 7. A fi eld LP tank regulator must
be used to limit the supply pressure to a maximum
of 14 inches WC (3.5 kPa). All piping should be sized
in accordance with the latest edition of ANSI
Standard Z223.1 (NFPA 54), National Fuel Gas
Code; in Canada, according to CSA B149. See
Tables 1, 6 & 7 (of this manual) 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.
3. Adequately support the piping to prevent strain on
the gas manifold and controls.
4. To prevent the mixing of moisture with gas, run the
take-off piping from the top, or side, of the main.
5. 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
Pipe directly into the combination valve (see Figure
10).
6. A 1/8 inch N.P.T . plugged tapping, accessible for test
gauge connection, must be installed immediately
upstream of the gas supply connection to the
appliance.
7. 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 exter nal to the jacket
(See Figure 10).
8. Make certain that all connections have been
adequately doped and tightened.
NOTICE: Use pipe joint sealant resistant to the action
of liquefied petroleum gases regardless of gas
conducted.
Check all pipe joints for leakage
using a soap solution or other approved method.
Never use an open fl ame or severe personal injury
or death may occur!
Figure 10- Pipe Installation, Standard Controls
Never use an open fl ame to detect
gas leaks. Explosive conditions may exist which
will result in personal injury or death.
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).
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).
Do not over tighten the inlet gas piping
into the valve. This ma y cause stresses that will crack
the valve!
17
PIPE INSTALLATION (Continued)
Table 7 - Gas Supply Pressure Requirements
Natural Gas Propane Gas
Heating V alue
Manifold Pressure
Single Stage Application3.5 in. WC10.0 in. WC
Two Stage Application - High Fire3.5 in. WC10.0 in. WC
Two Stage Application - Low Fire1.1 in. WC3.8 in. WC
Modulating Application - High Fire3.5 in. WC10.0 in. WC
Modulating Application - Low Fire0.9 in. WC3.5 in. WC
Never overfi re the duct furnace, as this
may cause unsatisfactory operation, or shorten the
life of the heater.
Check the gas input rate as follows (Refer to General
Safety Information section for metric conversions).
1. Turn off all gas appliances that use gas through the
same meter as the unit heater.
2. Turn the gas on to the unit heater.
3. Clock the time in seconds required to burn 1 cubic ft.
of gas by checking the gas meter.
4. Insert the time required to burn one cubic foot of gas
into the following f ormula and compute the input rate
3600 (Sec. per Hr.) x BTU/Cu./Ft.
= Input Rate
Time (Sec.)
For example , assume the BTU content of one cubic foot
of gas is 1000, and that it takes 18 seconds to burn one
cubic foot of gas.
3600 x 1000
= 200,000
18
NOTICE: If the computation exceeds, or is less than
95% of the gas BTU/hr. input rating (see Table 2),
adjust the gas pressure.
Adjust the gas pressure as follows:
1. NATURAL GAS: Best results are obtained when
the duct furnace is operating at its full rated input
with the manifold pressure of 3.5 inch WC (0.9 kP a).
Adjustment of the pressure regulator is not normally
necessary since it is preset at the factory. However,
fi eld adjustment may be made as follows:
a. Attach manometer at the 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 manif old pressure of 10.0
inch 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, f ollo w steps “a” through “d” abov e. If the unit is
not so equipped, the propane gas supply system
pressure must be regulated to attain this manifold
operating pressure.
*
INPUT
IN
1000
BTU
100
125
150
175
200
225
250
300
350
400
* This schedule is for units operating at normal altitudes of 2000 feet (610m)
or less. Special orifi ces are required for installations above 2000 f eet (610m).
When installed in Canada, any references to deration at altitudes in excess of
2000 feet (610m) are to be ignored. At altitudes of 2000 to 4500 feet (610 to
1372m), the unit heaters must be orifi ced to 90% of the normal altitude rating,
and be so marked in accordance with the ETL certifi cation.
HEATING
VALUE
MANIFOLD
PRESSURE
3
FT
/HR
ORIFICE DRILL
3
/HR
FT
ORIFICE DRILL
3
FT
/HR
ORIFICE DRILL
FT 3/HR
ORIFICE DRILL
3
/HR
FT
ORIFICE DRILL
3
/HR
FT
ORIFICE DRILL
3
/HR
FT
ORIFICE DRILL
FT 3/HR
ORIFICE DRILL
FT 3/HR
ORIFICE DRILL
3
/HR
FT
ORIFICE DRILL
1075 BTU/Ft
(40.1 MJ/m3)
3.5 Inch WC
(0.9 kPa)
96
42
120
42
140
42
163
42
186
42
210
42
233
42
280
42
326
42
372
42
3
2500 BTU/Ft
(93.1 MJ/m3)
10.5 Inch WC
PROPANETYPE OF GASNATURAL
(2.6 kPa)
40
54
50
54
60
54
70
54
80
54
90
54
100
54
120
54
140
54
160
54
3
NO. OF
BURNER
ORIFICES
4
5
6
7
8
9
10
12
14
16
PILOT ADJUSTMENT
1. Remove the PILOT ADJUSTMENT CAP.
2. Adjust the pilot screw to provide a properly sized
fl ame.
3. A proper fl ame is a soft, steady fl ame that envelops
3/8 to 1/2 inches (9.5 to 12.7mm) of the fl ame 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,
and counterclockwise to decrease the pressure. The
adjusted manifold pressure should not vary more
than 10% from the pressures specifi ed in Table 8.
19
10
11
7
12
13
Figure 11 - Burner Components – Intermittent Pilot Ignition
BURNER DRAWER COMMON PARTS:
1. MAIN BURNERS
2. BURNER MANIFOLD
3. AIR SHUTTERS
4. BURNER SPRINGS
5. MAIN BURNER ORIFICE
6. TRANSFORMER
7. PILOT TUBING
1
2
3
1
6
5
4
CONTROLS:
8A. MAIN GAS VALVE (HONEYWELL)
8B. MAIN GAS VALVE (WHITE RODGERS)
9. HONEYWELL IGNITOR
10. PILOT BURNER
11. PILOT ORIFICE
12. ELECTRODE/SENSOR LEAD
13. HIGH LIMIT
(LOCATED ON THE REAR HEADER PLATE OF THE
HEAT EXCHANGER - AIR INLET SIDE).
8A
O
F
F
O
N
8B
W
ARNING
V
M
1
Honeywell
S
8
C
6
0
ONTI
0M
N
UOUS
1
0
0
R
%
9
E-T
SHU
0
SEC.
T
OFF IP
TRIAL FOR
)
D
MV/PV
V
P
GN
2
3
4
IGNITION
)
24V
(GND
(BURNER
24V
5
TH-W
(OPT.)
6
7
9
R
Y
8
SPARK
9
20
OPERATION
NORMAL
(HARD FLAME)
LIFTING
(TOO MUCH AIR)
YELLOW TIPPING
(MARGINAL)
YELLOW FLAME
(TOO LITTLE AIR)
Never operate the unit beyond the
specified limits or severe damage to, and/or
premature failure of, the unit will result!
EXPLANATION OF CONTROLS
1. Each Separated Combustion Duct Furnace comes
equipped with a power vent system that consists of a
power ventor motor and b lower , pressure switch, and
sealed fl ue collector. (See Figure 15)
The addition of external draft hoods
or power ventors is not permitted. Addition of such
devices may cause serious unit malfunction or
failure.
2. The power ventor is energized by the room thermostat
when a demand for heat is sensed. The pressure
switch measures the differential pressure between
the air inlet and the exhaust vent systems. If the
differential is correct, the indirect spark ignition
system is energized.
Under no circumstances is the
unit to be fi red if the power ventor is not operable,
or severe personal injury or death may occur!
3. The indirect spar k ignition system consists of an
ignition module, a dual combination gas 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 fl ame is sensed by the
fl ame sensing circuit, the spark ceases, and the main
gas valve opens to supply gas to the main burners.
Once the thermostat is satisfi ed, the vent system and
gas valve are simultaneously de-energiz ed, stopping
all gas fl ow to the unit.
4. The high limit switch interrupts the fl ow of electrical
current to the main gas valve if the duct furnace
becomes overheated.
5. The optional fan switch delays the operation of the
fan for appro ximately 45 seconds once the thermostat
is closed, and continues fan operation for
approximately 65 seconds after the thermostat opens.
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.
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 f or
leaks.
NOTICE: Check all pipe joints for leakage using a soap
solution or other approved method.
Never use an open fl ame to detect
gas leaks. Explosive conditions may e xist which
could result in property damage, personal injury
or death.
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 heed this
warning could result in property damage,
personal injury or death!
2. T urn on electrical power. The duct furnace should now
be under the control of the thermostat. Set the
thermostat to it's highest setting, the power ventor
motor should start, and burner ignition occur. Tur n
the thermostat to the lowest setting. The burners and
power ventor should stop operating immediately.
Reset the thermostat to the desired operational
setting.
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
friction-locked, manually-rotated air shutters clockwise to
close, and counterclockwise to open.
For correct air adjustment, close the shutter until yellow
tips in the fl ame appear. Then, open the air shutter to the
point just beyond where the yellow tipping disappears.
Refer to Figure 12.
NOTICE: There may be momentary and spasmodic
orange fl ashes in the fl ame . This is caused by the
burning of airborne dust particles, and should not
be confused with yellow tipping, whic h is a stable, or
permanent, situation when there is insufficient
primary air.
Figure 12 - Main Burner Flames
NOTICE: The thermostat must be mounted on a
vertical, vibration-free surface, free fr om air currents,
and in accordance with the furnished instructions.
SHUT DOWN
1. Turn the valve selector knob to the "OFF" position.
2. Turn off the electricity.
3. To relight, follow "Initial Lighting" instructions.
21
MAINTENANCE
PERIODIC SERVICE
Open all disconnect switches and
secure in that position before servicing unit.
Failure to do so may result in personal injury or
death from electrical shock!
Gas tightness of the safety shutoff valves must be chec ked on at least an annual
basis.
To check gas tightness of the safety shut-off valv es, turn
off the manual valve upstream of the appliance
combination control. Remo ve 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 manometer, then turn the valv e
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 m ust be
replaced before putting appliance back in service.
NOTICE: The heater and vent system should be
checked once a year by a qualifi ed technician.
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 Table 3.
2. T urn off the manual gas v alve and electrical power to
the duct furnace.
3. T o clean or replace the main burners, open 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 aw ay 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 par ts are unobstructed. Inspect
and clean the 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 the “Operation” section of this manual (see
unit lighting instruction plate and the unit nameplate).
8. Check the burner adjustment. See “Primary Air
Shutter Adjustment” section in this manual.
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
fl ame on the main burners.
11.
Inspect and service the blower section of the system.
12. Check and test the operational functions of all saf ety
devices supplied with your unit.
GAS VALVE
MAIN
BURNERS
Under no circumstances should
combustible material be located within the
clearances specifi ed in T able 3. Failure to pr ovide
proper clearances could result in personal injury
or equipment damage from fi re!
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 suffi cient from the point where the tube does not slip in or out.
3) Flue Sizes:
100/175 units: 4 inch diameter fl ue outlet Reducer required – To be supplied by installer.
200/250 units: 5 inch diameter fl ue outlet (no adaptor required on fl ue).
300/400 units: 6 inch diameter fl ue outlet Increaser required – To be supplied by manufacturer.
4) See “Power Vent Position” in Installation section for instructions on how to adjust vent position from factory installed position.
23
Table 9 - Troubleshooting Guide
SYMPTOMS POSSIBLE CAUSE(S) CORRECTIVE ACTION
A. Flame lifting from
burner ports.
B. Flame pops back.
C. Noisy fl ame.
1. Pressure regulator set too high.
2. Defective regulator.
3. Burner orifi ce too large.
1. Excessive primary air.
2. Burner orifi ce too small.
1. Too much primary air.
2. Noisy pilot.
3. Irregular orifi ce causing whistle or
resonance.
4. Excessive gas input.
1. Reset manifold Pressure. Refer to
“Operation”.
2. Replace regulator section of combination gas valve or
complete valve.
3. Check with local gas supplier for
proper orifi ce size, and replace. Refer to “Operation”.
1. Close air shutter. Refer to
“Operation”.
2. Check with local gas supplier for
proper orifi ce size and replace.
Refer to “Operation”.
1. Close air shutter.
2. Reduce pilot gas. Refer to
“Operation”.
3. Replace orifi ce.
4. Reset manifold pressure. Refer to
“Operation”: Replace regulator section of combination gas valve
or complete valve; or Check with
local gas supplier for proper orifi ce
size, and replace. Refer to
“Operation”.
D. Yellow tip fl ame (some yellow tipping on propane
gas is permissible).
E. Floating fl ame.
F. Gas odor.
1. Insuffi cient primary air.
2. Clogged burner ports.
3. Misaligned orifi ces.
4. Clogged draft hood.
5. Air shutter.
6. Insuffi cient combustion air.
1. Blocked Venting.
2. Insuffi cient combustion air.
3. Blocked heat exchanger
4. Air leak into combustion chamber
or draft hood.
1. Shut off gas immediately.
2. Blocked heat exchanger/venting.
3. Drafts around heater.
4. Negative pressure in building.
5. Blocked draft hood.
1. Open air shutter. Refer to
“Operation”.
2. Clean main burner ports.
3. Replace manifold assembly.
4. Clean draft hood.
5. Check for dust or lint at air mixer
opening and around air shutter.
6. Check for obstruction in combustion air inlet cap and piping. See “Installation”.
1. Clean fl ue. Refer to “Installation”.
2. Check for obstruction in combustion air inlet cap
and piping. See “Installation”.
3. Clean heater.
4. Determine cause and repair
accordingly.
1. Inspect all gas piping and
repair.
2. Clean heat exchanger/fl ue.
3. Eliminate drafts. Refer to
“Installation”.
4. See “Installation”.
5. Clean draft hood.
24
Table 9 - Troubleshooting Guide
SYMPTOMS POSSIBLE CAUSE(S) CORRECTIVE ACTION
G. Delayed ignition.
H. Failure to ignite.
1. Excessive primary air.
2. Main burner ports clogged near
pilot.
3. Pressure regulator set too low.
4. Pilot decreases in size when main burners come on.
5. Pilot fl ame too small.
6. Drafts around ventor.
7. Improper venting.
1. Main gas valve off.
2. Lack of power at unit.
3. Thermostat not calling for heat.
4. Defective limit switch.
5. Improper thermostat or
transformer wiring at gas valve.
6. Defective gas valve.
7. Defective thermostat.
8. Defective transformer.
9. Loose wiring.
10. Defective ignition control.
1. Close air shutter. Refer to
“Operation”.
2. Clean main burner ports.
3. Reset manifold pressure. Refer
to “Operation”.
4. Supply piping is inadequately sized. Refer to “Installation”.
5. Clean pilot orifi ce. Refer to
“Operation”.
6. Eliminate drafts. Refer to
“Installation”.
7. Refer to ˆ“Installation”.
1. Open all manual gas valves.
2. Replace fuse or turn on power
supply.
3. Turn up thermostat.
4. Check limit switch with continuity
tester. If open, replace high limit.
5. Check wiring per wiring diagrams.
6. Replace gas valve.
7. Check thermostat and replace if
defective.
8. Be sure 115 volts is supplied to
the transformer primary, then check for 24 volts at secondary
terminal before replacing.
9. Check and tighten all wiring connections per diagrams.
10. Replace, if necessary. Also see
W, X, & Y symptoms.
J. Condensation of water
vapor.
K. Burner won't turn off.
1. Condensation of water vapor.
1. Poor thermostat location.
2. Defective thermostat.
3. Improper thermostat or
transformer wiring at gas valve.
4. Short circuit.
5. Defective or sticking gas valve.
6. Excessive gas supply pressure.
25
1. Refer to “Installation, Venting”.
1. Relocate thermostat away from
drafts.
2. Replace thermostat.
3. Check wiring diagrams.
4. Check operation at valve.
Look for short (such as staples
piercing thermostat wiring) and
correct.
5. Replace gas valve.
6. Refer to “Operation”.
Table 9 - Troubleshooting Guide
SYMPTOMS POSSIBLE CAUSE(S) CORRECTIVE ACTION
L. Rapid burner cycling.
M. Noisy power ventor.
N.
Pilot will not light or will not
stay lit.
1. Loose wire connections at gas valve or thermostat.
2. Excessive thermostat heat
anticipator.
3. Unit cycling on high limit.
4. Poor thermostat location.
5. Draft on pilot.
6. Defective ignitor control.
7. Defective high limit.
1. Power ventor wheel loose.
2. Power ventor wheel dirty.
3. Power ventor wheel rubbing
housing.
4. Bearings are dry.
1. Main gas valve off.
2. Pilot adjustment screw turned
too low on combination main gas
valve.
3. Air in gas line.
4. Incorrect lighting procedure.
5. Dirt in pilot orifi ce.
6. Extremely high or low gas
pressure.
7. Drafts around unit.
8. Pilot valve not opening (faulty
wiring).
9. No spark (faulty wiring).
10. Defective gas valve.
1. Tighten all connections.
2. Adjust thermostat for longer cycles. Refer to “Operation”.
3. Check for proper air supply across heat exchanger.
4. Relocate thermostat (do not mount thermostat on unit).
5. Eliminate drafts. Refer to
“Installation”.
6. Replace ignitor.
7. Jumper high limit switch terminals
1 and 2. If burner operates normally, replace switch.
1. Replace or tighten.
2. Clean power ventor wheel.
3. Realign power ventor wheel.
4. Oil bearings on power ventor motor. Refer to label on motor.
1. Open all manual gas valves.
2. Refer to “Operation”.
3. Purge air from gas line.
4. Follow lighting instruction label adjacent to gas valve.
5. Remove pilot orifi ce. Clean with
compressed air or solvent. Do
not ream.
6. Refer to “Operation”.
7. Eliminate drafts. Refer to
“Installation”.
8. Inspect and correct wiring.
9. Inspect and correct ignition system wiring. See symptoms W, X & Y.
10. Replace gas valve.
26
Table 9 - Troubleshooting Guide
SYMPTOMS POSSIBLE CAUSE(S) CORRECTIVE ACTION
O. Power ventor will not run.
P. Power ventor motor turns
on and off while burners
are operating.
1. Loose wiring.
2. Defective motor overload protector or defective motor.
3. Defective power ventor relay.
1. Fan relay heater element
improperly wired.
2. Defective ventor relay switch.
3. Motor protector cycling on and off.
4. Motor not properly oiled.
1. 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). See “Electrical
Connections”.
2. Replace motor.
3. Check 24V across 1 and 3 terminals on fan relay. If 24V is present, jumper terminals numbered 2 and 4. If motor runs,
the relay is defective and must be
replaced. If 24V in not present, check wiring per wiring diagrams.
1. Be sure ventor relay heater terminals are connected per
diagrams.
2. Replace ventor motor.
3. Check motor amps against motor
name plate rating, check voltage,
replace power ventor motor if
defective.
4. Refer to label on motor.
Q. Power ventor motor will
not stop.
R. Not enough heat.
T. Too much heat.
1. Improperly wired ventor relay.
2. Main burners not lighting while thermostat calls for heat.
3. Defective ventor relay.
1. Incorrect gas input.
2. Heater undersized.
3. Thermostat malfunction.
4. Heater cycling on high limit.
5. Check outside dampers if used.
1. Thermostat malfunction.
2. Heater runs continuously.
1. Check all wiring.
2. Refer to H & N Symptoms.
3. Replace ventor relay.
1. Refer to “Operation”.
2. This is especially true when heated space is enlarged. Have heat loss calculated and compare
to heater output (80% of input). Your gas supplier or installer can furnish this information. If heater is
undersized, add additional heaters.
3. Replace thermostat.
4. Check air movement through heat
exchanger. Check voltage to fan motor. Clean power ventor motor.
5. Adjust dampers accordingly.
1. Replace thermostat.
2. Check wiring diagrams; Check operation at valve. Look for short
(such as staples piercing thermo-
stat wiring) and correct: Replace
gas valve; Refer to “Operation”.
U. Cold air is delivered on
start-up
1. Fan relay heater element
improperly wired.
27
1. Be sure fan relay heater terminal
are connected per diagrams.
Table 9 - Troubleshooting Guide
SYMPTOMS POSSIBLE CAUSE(S) CORRECTIVE ACTION
V. Cold air is delivered during heater operation.
W. No spark.
X. Spark present but pilot does not light.
Y. Pilot lights — Main valve
does not energize.
1. Incorrect manifold pressure
or input.
2. Voltage to unit too high.
3. Air through put too high.
1. Thermostat not calling for heat.
2. No low voltage.
3. Spark gap closed or too wide.
4. Broken or cracked ceramic on
spark electrode.
1. Loose S8600 connections.
2. Improper gas pressure.
3. Is spark in pilot gas stream?
4. No pilot gas — do not use match
to test - presence of gas is easily
detected by the odor.
1. Loose S8600 connections.
2.
Cracked or broken sensor ceramic.
3. Check sensor/spark lead for
continuity.
4. Measure 24 volts from term.
MV to term. MV/PV.
1. Refer to "Operation".
2. Check motor voltage with fan running. Should be 115 volts AC.
3. Refer to "Operation".
1. Close thermostat contacts.
2. Check for 24V across
24V terminals of S8600.
3. Set gap to 0.1".
4. Replace pilot assembly.
1. Check all connections, term.
PV feeds 24V to pilot valve.
2. Check pressure — pressure that
is either too high or too low may cause a problem.
3. Spark should arc from electrode.
4. Check pilot line for kinks. Ensure
there are no drafts.
1. Check connections-term. MV feeds main valve.
2. Replace pilot assembly.
3. Replace if needed.
4. If present, replace main valve; if not, replace S8600 Igniter.
Z. Hi-Limit switch tripping.
1. Unit is overfi ring.
2. Air fl ow too low
3. Defective switch.
1. Manifold pressure too high; adjust.
Burner orifi ces may be too large:
verify/replace if req'd.
2. Increase air fl ow; check fan size.
Check for proper voltage.
3. Replace.
28
HOW TO ORDER REPLACEMENT PARTS
Please send the following information to your local representative; If further assistance is needed, contact the
manufacturer's customer service department.
• Unit number
• Serial Number (if any)
• Part description and Number as shown in the Replacement Parts Catalog.
LIMITED WARRANTY
SEPARATED COMBUSTION DUCT FURNACE
1. The “Manuf acturer” warrants to the original owner at original installation site that our Separated Combustion
Duct Furnace (“the Product”) will be free from defects in material or workmanship for one (1) year from the
date of shipment from the factory. If upon examination by the Man uf acturer the Product is sho wn to ha v e a
defect in material or workmanship during the warranty period, the Manufacturer will repair or replace, at its
option, that part of the Product which is shown to be defective.
2. This limited warranty does not apply:
(a) if the Product has been subjected to misuse or neglect, has been accidentally or intentionally
damaged, has not been installed, maintained or operated in accordance with the furnished written
instructions, or has been altered or modifi ed in any way by any unauthorized person.
(b) to any expenses, including labor or material, incurred during removal or reinstallation of the Product.
(c) to any damage due to corrosion by chemicals, including halogenated hydrocarbons, precipitated in
the air.
(d) to any workmanship of the installer of the Product.
3. This limited warranty is conditional upon:
(a) advising the installing contractor, who will in turn notify the distributor or manufacturer.
(b) shipment to the Manufacturer of that part of the Product thought to be defective . Goods can only be
returned with prior written approval of the Manufacturer . All returns must be freight prepaid.
(c) determination in the reasonable opinion of the Manufacturer that there exists a def ect in material or
workmanship.
4. Repair or replacement of any part under this Limited W arranty shall not extend the duration of the w arranty
with respect to such repaired or replaced part beyond the stated warranty period.
5. THIS LIMITED W ARRANTY IS IN LIEU OF ALL O THER W ARRANTIES, EITHER EXPRESS OR IMPLIED,
AND ALL SUCH OTHER WARRANTIES, INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE HEREBY DISCLAIMED
AND EXCLUDED FROM THIS LIMITED WARRANTY . IN NO EVENT SHALL THE MANUFACTURER BE
LIABLE IN ANY WAY FOR ANY CONSEQUENTIAL, SPECIAL, OR INCIDENTAL DAMAGES OF ANY
NATURE WHATSOEVER, OR FOR ANY AMOUNTS IN EXCESS OF THE SELLING PRICE OF THE
PRODUCT OR ANY PARTS THEREOF FOUND TO BE DEFECTIVE. THIS LIMITED WARRANTY GIVES
THE ORIGINAL OWNER OF THE PRODUCT SPECIFIC LEGAL RIGHTS. Y OU MAY ALSO HAVE OTHER
RIGHTS WHICH MAY VARY BY EACH JURISDICTION.
In the interest of product improvement, we reserve the right to make changes without notice.
29
SEPARATED COMBUSTION INDOOR DUCT FURNACE
UNIT NUMBER DESCRIPTION
Digit X X X X — 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 +
Item
N - Natural Gas
P - Propane Gas (LP)
K - Natural Gas w/100% Shutoff
Digit #9 - Ignition Control [IC]
2 - Spark Ignition
Digit #10 - Altitude [AL]
A - 0–1,999 ft. J - 8,000–8,999 ft.
B - 2,000–2,999 ft. K - 9,000–9,999 ft.
C - 3,000–3,999 ft. L - 10,000–10,999 ft.
D - 4,000–4,999 ft. M - 11,000–11,999 ft.
F - 5,000–5,999 ft. N - Local Gas Supplier Derate
G - 6,000–6,999 ft. P - Canadian High Altitude 2,000–4,500 ft.
H - 7,000–7,999 ft.
Digit #11 - Gas Control [GC]
A - Single Stage
B - T wo Stage
H - Electronic Modulation w/Room Sensing
J - Electronic Modulation w/Duct Sensing
K - Electronic Modulation w/Duct Sensing & Room Ovrd. Stat
L - Electronic Modulation w/External 4-20 mA Input
N - Electronic Modulation w/External 0-10 VDC Input
† Field Installed Accessories are not included in the Unit Number. All Field Installed
Accessories are entered as a separate line item using the catalog number which utilizes
“AS” as a prefi x. i.e: A7 becomes AS-A7.
A7 - Pressure Regulator 1/2-2 psi H5 - Low Ambient Control
F1 - 1-Stage T675A Ductstat M2-1 -
Note: Supply Voltages [SV] 2-7 include fi eld mounted step down transformer.
30
31
GAS EQUIPMENT
START-UP
Customer ____________________________________ Job Name & Number _________________________
PRE-INSPECTION INFORMATION
With power and gas off.
Type of Equip:
Serial Number_________________________ Model Number __________________________
Name Plate Voltage:_____________ Name Plate Amperage: _____________
Type of Gas:Natural LP Tank Capacity _______ lbs Rating: _ _____ BTU @ ____ °F
_______ kg _ _____ kw @ ____ °C
Duct Furnace
❐ Are all panels, doors, vent caps in place?
❐ Has the unit suffered any external damage? 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 fi eld 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.)
With power and gas off.
GENERAL
❐Make certain all packing has been removed.
❐ Tighten all electrical terminals and connections.
❐ Check all controls for proper settings.
❐ Inlet gas pressure. ____ in. WC or ____ kPa
❐ Pilot & main burner ignition.
❐ Manifold gas pressure. ____ in. WC or ____ kPa
GAS HEATING
With power and gas on.
❐ Check electronic modulation. Set at: __________
❐ Cycle and check all other controls not listed.
❐ Entering air temp. _____ °F or ____ °C
❐ Discharge air temp. (high fi re) ____ °F or ____ °C
❐ External static pressure _________ in. WC
❐ Cycle by thermostat or operating control.
❐ Combustion Reading: