heatco HP Series Installation and user guide

OPERATION, SERVICE
AND MAINTENANCE MANUAL
IAS 9-90:1991 Gas-Fired, Desiccant Type Dehumidifiers and Air Conditioners
Gas Unit Heaters, Gas Packaged Heaters, Gas Utility Heaters, And Gas-Fired Duct
Furnaces [ANSI Z83.8:2016 Ed.6]
Gas Unit Heaters, Gas Packaged Heaters, Gas Utility Heaters, And Gas-Fired Duct
Furnaces [CSA 2.6:2016 Ed.6]
Gas-Fired Central Furnaces [ANSI Z21.47:2016 Ed.7]
Gas-Fired Central Furnaces [CSA 2.3:2016 Ed.7]
This manual must be kept with the appliance for future reference.
HP-USM-MAN-E-2016-2
HP SERIES
AIR HEATER MODULE
3035443

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The Air Heater modules covered by these instructions become a component of a “Listed” product, subject to
the guidelines of application provided in these instructions and designated by the Certifying Agency in the
Manufacturer’s Listing Procedure
The information provided in this manual applies to the air heater module, installed in the air handling /
dehumidification unit and to its operation, maintenance, and service. Refer to the information provided by
the equipment manufacturer for all other components.
Table of Contents
Inspection…………………………………………………………………..3
Unit Installation / Clearances……..…………………………………..3
Combustion Air Supply…………………………………………………...3
Outdoor Installation…………………………..………………………….4
Indoor Installation…………………………………………………..……5
Vertically Vented – Category I ……………………………….5, 6
Horizontally Vented – Category III………………………….6, 7
Separated Combustion …………………………………………7, 8
Gas Supply Piping and Connections…………………………………. 9
Gas Input………………………………………………………….…………10
Operation and Safety …………………………………………………… 10
Start-up……….…………………………………………………... 10
Failure to Ignite…………………………….………………..…..11
Gas Pressures & Adjustment, Gas Valve…….………...….. 11, 12
Burner Flames…………………………………………….…..…. 12
Shutdown…………………………………………………….….…13
Normal Operation…………………………………………..……13
Operating Controls ……………………………………………….……....13
Annual Maintenance & Inspection …………………………………….14
Module Component ID ……………………………………………………15

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Inspection on Arrival
1. Inspect equipment upon arrival in accordance with unit manufacturer’s instructions and follow their
recommendations if any damage has occurred.
2. Prior to installation locate manufacturer’s rating plate and verify that furnace is equipped for the available fuel
supply and power supply at the point of installation.
Unit Installation, Location & Clearances
Verify the following at installation before placing the equipment into service:
1. Electrical supply matches the voltage marked on the furnace module Rating Plate.
2. Gas supply provided matches the Gas Type marked on the furnace module Rating Plate.
3. Furnace module is installed in orientation marked on vestibule. Orientation is specific to airflow direction
through the heating section of the unit.
4. There is an adequate supply of fresh air for the combustion and ventilation process. Combustion air
openings in the cabinet should be sized to provide 1 sq. in of free area per 4000 Btuh of input.
5. A properly designed vent system is connected to the furnace module unit to convey the products of
combustion (flue gases) outside the building. For outdoor applications be sure the flue gases are directed
away from any combustion air inlets.
6. Furnace module is installed in a non-combustible duct or cabinet. Module may be located on positive or
negative side of circulating air blower.
7. An air flow proving switch is installed and wired to prove operation of the system circulating air blower.
8. An auxiliary Manual Reset Limit is installed to shut-off furnace module in the event of low airflow conditions
due to filter blockage, coil blockage and or damper failure.
9. A drain tube is installed for disposal of condensate, if the furnace module is equipped with modulating
controls or is located downstream of cooling system.
10. Equipment access panels and doors are sized and located to provide easy access for servicing, adjustment
and maintenance of the furnace installed. Provide at least 36” (0.9m) clearance for removal of access panel.
Combustion Air Supply
All gas fired furnaces need an ample supply of air for proper and safe combustion of the fuel gas. If sufficient
quantities of combustion air are not available to the heater, poor combustion and inefficient operation will result. The
heating unit cabinet combustion air openings should be sized to provide 1 sq. in of free area per 4000 Btuh of input.
For outdoor installations combustion air inlet and flue gas outlet must be located in the same pressure zone to
minimize effects of wind on burner and heater performance.
Indoors, locate heating unit to ensure an adequate supply of fresh air to replace air used in the combustion and
ventilation process. Install air openings that provide a total free area in accordance with the National Fuel Gas Code
(ANSI Z223.1 or NFPA 54) in the United States or CAN/CGA B-149 Installation Code in Canada.
WARNING!
The presence of chlorine vapors in the combustion air supplied to gas-
fired heaters presents a substantial corrosion hazard.
WARNING!
This furnace is not listed or suitable for drying or process applications. Use in
such applications voids any warranty and manufacturer disclaims any
responsibility for the furnace and /or application.

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Outdoor Installation
The venting system is designed for direct discharge of flue gases to the outdoors. The vent discharge opening should
be located to provide an unobstructed discharge to the outside. Vent duct should pitch down toward outlet, to ensure
that any condensate that occurs in vent duct drains away from combustion blower fan housing. The duct opening
should be protected by a ½ in. x ½ in. (12mm x 12mm) mesh screen. An optional rain hood may be used over the
discharge opening to prevent wind driven rain from entering the vent duct but should not intersect the flue gas
discharge path. See Figure 1 below.
Figure 1 – Outdoor Horizontal Venting
Outdoor units must be individually vented, unless provided with a special vent system by the manufacturer.
Where sufficient clearance for proper horizontal venting cannot be provided, or in jurisdictions requiring a 4-foot
(1.23 m) separation between flue gas discharge and combustion air inlet, flue gases need to be vented vertically.
Refer to Figure 2 for preferred venting arrangements.
Vent pipe must terminate at least 12 inches (305 mm). above the cabinet. The vent must be located on the same
side of the appliance as the combustion air inlet opening. Condensation in the vent pipe is likely during heater
operation. A capped “T” fitting is used to collect condensate from the vent pipe. Provide a drain fitting at the base of
“T” to remove condensate. Disposal of condensate must be in accordance with local codes and ordinances.
Figure 2 – Outdoor Vertical Venting

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Do not locate unit near building ventilators or exhausts, or areas where corrosive chemical vapors can
be drawn into combustion air supply.
Do not install units in locations where flue products can be drawn in the adjacent building openings
such as windows, fresh air intakes, etc.
Indoor Installations
Location
Locate heating unit to ensure an adequate supply of fresh air to replace air used in the combustion and ventilation
process. The heating unit must be installed in a location with adequate clearances to provide for adequate
combustion air space, service and inspection, and proper clearances from combustible construction. The heating unit
shall be located in such a manner that it does not interfere with the circulation of air in the heated space.
Venting Indoor Installations
Furnace modules must be connected to a venting system to convey flue gases outside of the heated space.
Proper venting of the heating units is the responsibility of the installer. Venting materials are provided by others.
Vertically Vented Duct Furnaces – Category I (See Figure 3)
Non-condensing appliances operating at negative pressure are classified Category I. Category I Vent systems must be sized
and installed in accordance with the National Fuel Gas Code, ANSI Z223.1 (NFPA 54) Chapter 13 in the United
States or CAN/CGA-B149 Natural and propane gas installation code, Section 8 and Annex C, in Canada. UL Listed
Type B Vent or single wall metal pipe may be used. If used, single wall vent pipe shall have seams and joints sealed with
pressure sensitive aluminum tape or silicone rubber sealant, rated for 480 oF (249 oC) or higher. Joints should be secured with at
least two corrosion resistant fasteners. When custom designed systems provided by a vent system manufacturer are field
installed, proper heating unit operation must be verified, including flue gas analysis of each heater.
1. Maximize the height of the vertical run of vent pipe. A minimum of five (5) feet (1.5m) of vertical pipe is required.
The top of the vent pipe must extend at least 18 in. ( 457 mm) above the highest point on the roof. (Use Listed
Type B vent for external runs).
2. An approved weatherproof vent cap must be installed to the vent termination.
3. Horizontal runs should be pitched upward ¼” per foot (21mm/m) and should be supported at 3 foot (1m)
maximum intervals. It is best to keep horizontal runs less than 75% of vertical height to avoid possible need to
upsize vent pipe.
4. Design vent pipe runs to minimize the use of elbows. Each 90o elbow is equivalent to 5 feet (1.5m) to 7 feet
(2.13m) of straight vent pipe run depending on pipe diameter.
5. Vent pipe should not be run through unheated spaces. If such runs cannot be avoided, insulate vent pipe to
prevent condensation inside vent pipe. Insulation should be a minimum of ½” (12.7mm) thick, foil faced material
suitable for temperatures up to 500 oF (260 oC).
6. Dampers must not be used in vent piping runs. Spillage of flue gases into the occupied space could result.
7. Vent connectors serving Category 1 heaters must not be connected into any portion of a mechanical draft system
operating under positive pressure.
WARNING!
Gas-fired furnaces are not designed for use in hazardous atmospheres
containing flammable vapors or combustible dust, in atmospheres containing
chlorinated or halogenated hydrocarbons, or in applications with airborne
substances containing silicone.

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Table 1 – Vent Connector Diameter
Gas Input (Btuh) Gas Input (W) Diameter of Flue Vent
50,000 – 149,999 21,980 – 43,958 5” (126 mm)
150,000 – 400,000 43,960 – 117,228 6” (152 mm)
401,000 – 600,000 117,229 – 175,842 7” (178mm)
Figure 3 – Indoor Vertical Venting
Condensate
Drain
Roof
18 in. Min.
(457 mm)
Thimble
“H”
Vertical Height
Listed Vent
Terminal
Use Insulated
Vent Outdoors
“L”
Lateral Run
1/4in. (6mm) pitch per
1ft. (305mm)
horizontal run
See Table 1 for minimum
vent diameter for input rating
See Tables in
ANSI Z223.1 or CSA B149.1
for “H” and “L” Dimensions
Horizontally Vented Duct Furnaces -Category III System (See Figure 4)
Pressures in Category III venting systems are positive and therefore care must be taken to avoid flue products from
entering the heated space. Use only Category III vent materials listed to UL1738 / ULC S636 for vent pipe and
fittings.
All field installed vent pipe and fittings must be from the same manufacturer. DO NOT intermix vent system
parts from different vent manufacturers. Follow instruction provided with approved venting materials used.
All vent pipe joints must be sealed to prevent leakage into the heated space. Follow instruction provided with
approved venting materials used. See Table 1 above for proper sizing of vent pipe diameter.
The total equivalent length of vent pipe must not exceed 50 ft. (15.25m). Equivalent length of 5 or 6 in. 90o elbows
is 5 ft. (1.5 m), and for a 7in. 90o elbow is 7 feet (2.13 m). 45o Elbows are half of the equivalent length of 90o.
The vent system must also be installed to prevent collection of condensate. Pitch horizontal pipe runs downward ¼
in. per foot (21mm per meter) toward the outlet to permit condensate drainage. Insulate vent pipe exposed to cold
air or routed through unheated areas. Insulate vent pipe runs longer than 10 ft. (3m). Insulation should be a minimum
of ½ in. (12mm) thick foil faced material suitable for temperatures up to 500 oF. Maintain 6in. (152mm) clearance
between vent pipe and combustible materials.
A Tee Fitting termination or Vent Cap listed for horizontal venting must be provided. Termination inlet diameter must
be same as the required vent pipe diameter. The vent terminal must be at least 12 in. (305mm) from the exterior wall
that it passes through to prevent degradation of building material by flue gases. The vent terminal must be located at
least 18 inches (0.45m), above grade, or in snow areas, above snow line to prevent blockage. Additionally, the vent

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terminal must be installed with a minimum horizontal clearance of 4 ft. (1.2m) from electric meters, gas meters,
regulators or relief equipment.
Figure 4 – Indoor Horizontal Venting
EACH APPLIANCE MUST HAVE ITS OWN INDIVIDUAL VENT PIPE AND TERMINAL.
Do not connect vent system from horizontally vented units to other vent systems or a chimney.
Through the wall vents shall not terminate over public walkways, or over an area where condensate or vapor could
create a nuisance or hazard. Provide Vent termination clearances to building or structure features as follows:
Structure Minimum Clearance
Door, Window or gravity inlet 4 ft. (1.2 m) below
4 ft. (1.2 m) horizontally
1 ft. (305 mm) above
Forced air inlet within 10 ft. (3m) 3 ft. (.91 m) above
Adjoining building or parapet 6 ft. (1.8 m)
Adjacent public walkways 7 ft. (2.1 m) above grade
Two-Pipe Separated Combustion Systems
The furnace must be mounted with the burner section in a reasonably airtight vestibule compartment, as these
systems provide combustion air from outside the heated space and vent the products of combustion outdoors.
Additionally the heating unit must include the following:
1.) For vent pipe and fittings conveying flue gases, use only Category III vent materials listed to UL1738 /
ULC S636 from same vent manufacturer. DO NOT intermix vent system parts from different vent
manufacturers. Follow instruction provided with approved venting materials used.
2.) For combustion air piping, use of 24-gauge galvanized steel single wall pipe is acceptable. Tape joints with
aluminum foil tape and secure with corrosion resistant screws.
3.) Inlet air pipe must be same size as exhaust vent pipe based on input ratings.
4.) Exhaust and vent piping must not exceed a combined 50 equivalent feet in length. Minimize use of elbows.
Each 90o elbow is equivalent to 5 feet (1.5m) to 7 feet (2.13m) of straight vent pipe run depending on pipe diameter.
5.) See Figure 5 for recommended vent terminations and air inlet fittings for venting configuration. Proper
installation of air inlet and flue gas exhaust piping are essential to proper operation of the heat module.
NOTE: The inlet and outlet terminals must be located in the same pressure zone to provide for safe
appliance operation.

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Separated combustion systems may not be common vented. Each heater must have its own
individual air supply and flue gas exhaust vent.
If vent system application cannot meet the criteria provided or in diagrams below, contact a manufacturer of venting
systems and materials for assistance with system design.
Figure 5 – Separated Combustion Venting
Horizontal Venting
Note: Be sure that the vent cap used for horizontal venting applications is approved for horizontal application.
Certain manufacturer’s vent terminals are approved for vertical installation only.
Vertical Venting

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Gas Supply, Piping and Connections
1. Installation of piping must conform with local building codes and ordinances, or in the absence of local codes with
ANSI Z223.1 the National Fuel Gas Code. In Canada, installation must be in accordance with CAN/CGA –B149.1
for Natural gas and B149.2 for propane units.
2. Properly support gas valve with back-up wrench, during supply pipe installation.
3. Gas piping must be sized for the total Btu input of all units (heaters) serviced by a single supply.
4. Be sure that gas regulators servicing more than one heater have the proper pipe and internal orifice size for the
total input of all heaters serviced by the regulator.
5. Minimum inlet gas pressure required for Natural gas operation is 5.0 “w.c. and for Propane (LP) gas is 11.0”
w.c. Maximum inlet pressure for either gas is 13.5” w.c., with the furnace operating.
6. A 1/8” NPT tap is provided on the inlet side of the gas valve to the heater (See Figure 8). A fitting suitable for
connection to a pressure gauge capable of measuring gas pressure should be connected to each heater
serviced by a single regulator so that gas pressure at each heater can be measured with all heaters in operation.
(See Figure 6)
Figure 6
7. A drip leg (sediment trap) and a manual shut off valve must be provided immediately upstream of the gas control
on the heating unit. To facilitate servicing of unit, installation of a union is recommended. (See Figure 7)
Figure 7
The individual duct furnace inlet gas supply pipe connection size is ¾” NPT for gas inputs up to 400,000
Btuh and 1” NPT for gas inputs between 401,000 and 600,000 Btuh for all control systems.
Unit 1 Unit 2 Unit 3
Max. 13.5” w.c.
Min. 5.0” w.c. Natural Gas
Min. 11.0” w.c. Propane Gas
Pressure
Regulator
Gas
Supply
WARNING !
1. All field gas piping must be pressure /
leak tested prior to operation. NEVER
use and open flame to check for leaks.
Use a soap solution or other leak
detecting solution for testing.
2. Gas pressure to appliance controls
must never exceed 13.5” w.c. (1/2 PSI)
WARNING !
1. When pressure testing at ½ PSI or
less, close the manual shut-off valve
on the appliance before testing.
2. When pressure testing gas supply
line at ½ PSI or higher, close manual
gas valve and disconnect heater from
supply line to be tested. Cap or plug
the supply line.

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Gas Input Rate
The correct heat capacity of the heater module is controlled by the burner orifices and the gas manifold pressure.
The manifold pressure is factory set, but should be checked at the time of start-up as described below.
Operating & Safety Instructions
1. This heater module does not have a pilot. It is equipped with a direct spark ignition device that
automatically lights the gas burner. DO NOT try to light burners by hand.
2. BEFORE OPERATING, leak test all gas piping up to heater gas valve. Smell around the unit area for
gas. DO NOT attempt to place heater in operation until source of gas leak is identified and corrected.
3. Use only hand force to push and turn the gas control knob to the “ON” position. NEVER use tools. If
knob does not operate by hand, replace gas valve prior to staring the unit. Forcing or attempting to
repair the gas valve may result in fire or explosion.
4. Do not attempt to operate unit, if there is indication that any part or control has been under water. Any
control or component that has been under water must be replaced prior to trying to start the unit.
Start-up
1. Turn thermostat or temperature controller to its lowest setting
2. Turn off gas supply at the manual shut-off valve
3. Turn off power to the unit at the disconnect switch.
4. Remove access panel or open door to unit vestibule housing the gas heater.
5. Move gas control knob to “Off” position.
6. Install a tapped fitting for attachment to a manometer, or other gauge suitable for 14.0” w.c., in the inlet
pressure tap, and for 10.0” w.c., in the manifold pressure tap.
7. Wait 5 minutes for any gas to clear out. If you smell gas, see Step 2 above and correct leak. If you
don’t smell gas or have corrected any leaks, go to the next step.
8. Turn gas control knob to “On” position
9. Open all manual gas valves
10. Turn power on at disconnect switch
11. Set thermostat or controller to its highest position to initiate call for heat and maintain operation of
unit.*
12. Draft Inducer will run for a 15 to 30 second pre-purge period (See Sequence of Operation provided)
13. At the end of the pre-purge the direct spark will be energized and gas valve will open
14. Burners ignite.
*Note: If modulating controls are provided on heater module, a separate set-up sheet is included with this
manual. Refer to that set-up sheet for complete start-up instructions
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.

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Failure to Ignite
1. On the initial start-up, or after heating unit has been off long periods of time, the first ignition trial may
be unsuccessful due to need to purge air from manifold at start-up.
2. If ignition does not occur on the first trial, the gas and spark are shut-off by the ignition control and the
control enters an inter-purge period of 15 seconds, during which the draft inducer continues to run.
3. At the end of the inter-purge period, another trial for ignition will be initiated.
4. Control will initiate up to three ignition trials on a call for heat before lockout of control occurs.
5. Control can be brought out of lockout by turning thermostat or controller to its lowest position and
waiting 5 seconds and then turning back up to call for heat. Controls provided will automatically reset
after one hour and initiate a call for heat.
Manifold Pressure Adjustment
A pressure tap is provided in each furnace module manifold for measuring the gas manifold pressure.
Manifold pressure must be checked at start-up and during any service or maintenance. All control systems
require a manifold pressure of 3.40 to 3.50 in. w.c. at maximum input on Natural Gas, and 10.0 in.
w.c. on Propane Gas at rated input. See Fig. 8 for Gas Valve adjustment locations.
For two stage and modulating control applications, verify proper low fire adjustments as outlined in the
“Sequence of Operation” sheet provided in the instruction package.
Figure 8A – Honeywell VR8305Q Gas Valve
Figure 8B – White Rodgers 36H Gas Valve
1/8” NPT Inlet
Pressure Tap
2
nd
Stage (Hi Fire) Manifold
Pressure Adjustment
(3/32” Allen Key)
1
st
Stage (Lo Fire) Manifold
Pressure Adjustment
Manual Shut-off
Control Knob
Electrical
Connection Block
1/8” NPT Inlet
Pressure Tap
Manifold Pressure Adjustment
Remove Brass cap and adjust
with plastic screw
Electrical
Connection Block
Manual Shut-off

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Figure 8C – Honeywell V8944 Gas Valve
Burner Flames
Prior to completing the start-up, check the appearance of the main burner flame. See Figures below for flame
characteristics of properly adjusted Natural gas systems.
Figure 9A Figure 9B
1. The burner flame should be predominately blue in color and well defined and centered at the tube entry as
shown in Figures above. Distorted flame or yellow tipping of natural gas flame, or a long yellow flame on
propane, may be caused by lint and dirt accumulation inside burner or at burner ports, at air inlet between burner
and manifold pipe, or debris in the main burner orifice. Soft brush or vacuum clean affected areas.
2. Poorly defined, substantially yellow flames, or flames that appear lazy, indicate poor air supply to burners or
excessive burner input. Verify gas supply type and manifold pressure with rating plate.
3. Poor air supply can be caused by obstructions or blockage in heat exchanger tubes or vent discharge pipe.
Inspect and clean as necessary to eliminate blockage. Vacuum any dirt or loose debris. Clean heat exchanger
tubes with stiff brush. Poor flame characteristics can also be caused by undersized combustion air openings or
flue gas recirculation into combustion air supply. Increase air opening size or re-direct flue products to prevent re-
circulation.
4. Reduced air delivery can also be the result of fan blade slippage, dirt accumulation in the fan blade or low
voltage to draft inducer motor. Inspect draft fan assembly and be sure fan blade is secure to motor shaft. Check
line voltage to heater.
Burner Flame @ Start-up 1.2” w.c. Manifold
Pressure Draft Inducer – High Speed
Burner Flame @ High Fire 3.5” w.c. Manifold
Pressure Draft Inducer – High Speed

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Shutdown
1. Set thermostat or controller to lowest setting.
2. Turn off electrical supply to unit at disconnect switch.
3. Turn off manual gas supply.
4. Disconnect manifold and inlet pressure taps and re-install pipe plugs
5. Replace vestibule access panel or close door.
Normal Operation
1. Turn on electrical supply to unit at disconnect switch
2. Turn on manual gas supply
3. Set Thermostat or Temperature controller to desired temperature.
4. Information outlining the normal Sequence of Operation and Wiring Diagram for the control system supplied with
the furnace model is enclosed with this instruction.
Operating Controls
Ignition control
Direct spark ignition with flame supervision and 100% safety shut-off, multiple ignition trials on call for heat, pre-purge and post-
purge and auto reset on lockout after one (1) hour. Control incorporates a diagnostic LED.
Refer to Sequence of Operation and Control Diagnostic data sheets provided in the instruction package for a detailed description
of the control features, operation and troubleshooting for the model control installed.
Air Pressure Switch
A combustion air pressure switch is provided as part of the control system to verify airflow through draft inducer by monitoring the
difference in pressure between the draft inducer and the atmosphere. If sufficient negative pressure is not present, indicating lack
of proper air movement through heat exchanger, the switch opens shutting off gas supply though the ignition control module. On
units with two speed draft inducer operation, a dual air pressure switch is used, monitoring high and low speed pressures. The air
pressure switches have fixed settings and are not adjustable.
Rollout Switch (Manual Reset)
The heater module is equipped with manual reset rollout switch(es) in the event of burner flame rollout. The switch will open on
temperature rise and shut-off gas supply through the ignition control module. Flame rollout can be caused by insufficient airflow for
the burner firing rate (high gas pressure), blockage of the vent system or in the heat exchanger. The furnace module should not
be placed back in operation until the cause of rollout condition is identified. The rollout switch can be reset by pressing the button
on top of the switch.
High Limit Switch
The heater module is equipped with a fixed temperature high limit switch mounted on the vestibule panel that shuts off gas to the
heater through the ignition control module in the event of high temperatures in the air tunnel due to low circulating airflow over the
heat exchanger. Determine the cause of the reduced air flow and correct.
Note: The limit is an automatic recycle type and on circulating air fan failure, heater will cycle on limit resulting in possible heat
build-up. Prolonged operation under this condition can cause heat damage to components and cabinet structure.
Circulating Airflow Proving Switch
The installation of an airflow proving switch in the cabinet or duct is recommended, to prevent operation of the gas heater in
the event of failure of the circulating air fan or low airflow caused by dirty or blocked filters or restriction of the air inlet or outlet to
the unit. The air switch should be located upstream of the heating section in the duct or cabinet.

14
Inspection & Maintenance
Turn off all electrical power to the unit before inspection and servicing.
Periodic Inspection
Periodic maintenance inspections should be conducted during the heating season to ensure that combustion air
openings are clear and free of any dirt or debris that might restrict combustion air. Also, inspect vent stack for any
deterioration, blockages or debris. Correct any conditions that might result in unsatisfactory operation.
Inspect condensate drains during summer air conditioning operation to insure there are no blockages.
Annual Air Heater Module Inspection
The heater module should be inspected annually by a qualified service agency. The condition of the burners, heat exchanger,
draft inducer, vent system, operating controls and wiring should be determined. Check for obvious signs of deterioration,
accumulation of dirt and debris and any heat or water related damage. Any damaged or deteriorated parts should be replaced
before the unit is put back into service.
1. Clean burners, heat exchanger, draft inducer and vent ducts as outlined on Page12.
2. Check Heat Exchanger for cracks. If any are present, replace heat exchanger before putting unit back into service.
3. Check the attachment point of the furnace module to the cabinet or ducts to verify that they are airtight.
4. Check the automatic gas valve to ensure that the gas valve seat is not leaking.
5. Check connection terminals to make sure they are safe and inspect the wiring for any deterioration.
6. Label all wires prior to disconnection when servicing unit. Wiring errors can cause improper or dangerous
operation. Verify proper operation after servicing.
Air Heater Module Operation Check
1. Turn on power to the unit and set thermostat or heat controller to call for heat, allowing furnace module to operate.
2. Check for proper start-up and ignition as outlined in “Start-Up” on Page 10.
3. Check the appearance of the burner flame (See Figure 9A and 9B on Page 12).
4. Return thermostat or heat controller to normal setting.
5. Refer to the appliance manufacturer’s instructions for annual maintenance procedures on the complete unit.
If any of the original wiring needs to be replaced it must
be replaced with wiring materials suitable for 105oC.
CAUTION !

15
Module Component ID
Rollout
Switch
Flame Sensor
Combustion Air
Pressure Switch
Manifold
Pressure
Tap
Spark Igniter
Hi Limit
Switch
Induced Draft
Fan Assy.
Draft Inducer
Motor
Motor Support
Bracket

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Heatco Inc.
50 Heatco Court
Cartersville, Ga. 30120