Sequence Of Operation - International comfort products A Series Installation Instructions Manual

6. Carefully remove burner insulation assembly, Insulation
MUST be replaced before reassembly.
7. Clean heat exchanger openings with a vacuum and a soft
brush (Fig. 67).
Representative drawing only, some models may vary in appearance.
Fig. 67 - - Cleaning Heat Exchanger Cell
NOTE: After cleaning, inspect the heat exchangers to ensure they
are free of all foreign objects that may restrict flow of combustion
products.
8. Reverse items 6. through 1. for reassembly. Torque burner
screws to 45 inch- -pound to ensure a tight burner seal.
9. Refer to furnace wiring diagram and reconnect wires to
burner thermal switch, gas valve, igniter, and flame sensor.
10. Turn on gas and electrical supplies to furnace.
11. Check furnace operation through two complete heat operat-
ing cycles.
12. Check for gas leaks.
WARNING
!
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Never purge a gas line into a combustion chamber. Never
test for gas leaks with an open flame. Use a commercially
available soap solution made specifically for the detection
of leaks to check all connections. A fire or explosion may
result causing property damage, personal injury or loss of
life.
13. Replace main furnace door.
Secondary Heat Exchangers
The condensing side (inside) of the secondary heat exchanger
CANNOT be serviced or inspected without complete removal of
the heat exchanger assembly. Detailed information on heat
exchanger removal can be obtained from your Distributor.
WINTERIZATION
CAUTION
!
UNIT AND PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in unit component or
property damage.
If the furnace is installed in an unconditioned space where the
ambient temperatures may be 32_ F (0_ C) or lower, freeze
protection measures must be taken to prevent minor property
or product damage.
58
Since the furnace uses a condensing heat exchanger, some water
will accumulate in the unit as a result of the heat transfer process.
Therefore, once it has been operated, it cannot be turned off and
left off for an extended period of time when temperatures will
reach 32_F (0_C) or lower unless winterized. Follow these
procedures to winterize your furnace:
UNIT COMPONENT DAMAGE HAZARD
Failure to follow this caution may result in damage to the
furnace and other property damage.
Do not use ethylene glycol (automotive antifreeze coolant or
equivalent). Failure of plastic components may occur.
1. Obtain propylene glycol (RV/swimming pool antifreeze or
equivalent).
2. Turn off gas and electrical supplies to your furnace.
3. Remove furnace control door.
4. Remove the top unused rubber plug from the port on the
A190291
collector box opposite the condensate trap.
5. Connect a field supplied 3/8- -in. (9.5- -mm) ID tube to the open
port on the collector box.
6. Insert a field supplied funnel into the tube.
7. Pour one quart (liter) of anti- -freeze solution into the funnel/
tube. Antifreeze should run through the inducer housing,
overfill condensate trap and flow to an open drain.
8. Replace the rubber plug in the port on the collector box.
9. Remove the middle unused rubber plug from the port on the
collector box opposite the condensate trap.
10. Repeat Steps 5 through 8.
11. If a condensate pump is used, check with pump manufacturer
to verify pump is safe for use with antifreeze used. Allow
pump to start and pump anti- -freeze to open drain.
12. Replace main door.
13. When furnace is re- -started, flush condensate pump with clear
water to check for proper operation before re- -starting furnace.
14. Propylene glycol need not be removed before re- -starting
furnace.

SEQUENCE OF OPERATION

NOTE: Furnace control must be grounded for proper operation or
control will lock out. Control is grounded through green/yellow
wire routed to gas valve and gas valve mounting bracket screw.
Follow the sequence of operation through the different modes.
Read and follow the wiring diagram very carefully.
The blower door must be installed for power to be conducted
through the blower door interlock switch ILK to the furnace
control CPU, transformer TRAN, inducer motor IDM, blower
motor BLWM, hot- -surface igniter HSI, and gas valve GV.
Sequence of Operation - - Heating
1. Call for Heat
A call for heat is intiated when a connection is observed
between thermostat terminals "R" & "W".
a. Pressure Sensor Verification:The control operates the
b. Pre- -purge: The heating cycle begins with operation of the
c. Igniter Warm- -Up: After the pre- -purge timer expires, the
NOTE: Inducer motor shuts off during igniter warm up period
and then comes back on for the ignition trial.
Specifications subject to change without notice.
CAUTION
!
inducer in a manner to verify the pressure sensor null value
and span operation are within specification. If the system
is operating correctly, this test takes only a few seconds. If
the system is not functioning properly, the control times out
after a maximum 90 seconds and displays the proper fault
code.
inducer at "Pre- -purge" setting for the 30 seconds.
control will set the inducer to the "Igniter Warm- -Up"
setting and energize the igniter for the Igniter Warm- -up
period of 17 seconds.
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