GM9S80 Service Manual
SYSTEM OPERATION
5
1. 115 VAC power applied to furnace.
2. Integrated ignition control module performs internal
checks.
3. Integrated ignition control module LED will light.
4. Integrated ignition control monitors safety circuits
continuously.
5. Furnace awaits call from thermostat.
1. R and W thermostat contacts close, initiating a call
for heat.
2. Integrated control module performs safety circuit
checks.
3. The induced draft blower is energized causing pres-
sure switch contacts to close. Induced draft blower
remains energized for pre-purge period.
4. Ignitor warm up begins after pre-purge is completed.
5. Gas valve opens at end of ignitor warm up period, de-
6.
within seven (4) seconds after the gas valve is ener-
is present.
7. Circulator blower is energized on heat speed following
8. Furnace runs, integrated control module monitors
safety circuits continously.
9. R and W thermostat contacts open, allowing the gas
10. -
teen (15) - second post purge.
11. Circulator blower is de-energized following a selectable
12.
-
tomize the comfort level.
The normal operational sequence in cooling mode is as
follows:
1. R and Y thermostat contacts close, initiating a call for
cool.
2. Integrated control module performs safety circuit
checks.
3. Outdoor fan and compressor are energized.
4. Circulator blower is energized on cool speed following
5. Furnace circulator blower and outdoor cooling unit
run, integrated control module monitors safety circuits
continuously.
6. R and Y thermostat contacts open, completing the call
for cool.
7. Outdoor fan and compressor are de-energized.
8. -
9.
The normal operational sequence in fan only mode is as
follows:
1. R and G thermostat contacts close, initiating a call for
fan.
2. Integrated control module performs safety circuit
checks.
3. Circulator blower is energized on heat speed.
4. Circulator blower runs, integrated control module
monitors safety circuits continuously.
5. R and G thermostat contacts open, completing the call
for fan.
6. Circulator blower is de-energized.
7.
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-
The wiring harness is an integral part of this furnace. Field
alteration to comply with electrical codes should not be re-
Refer to the wiring diagram for wire routings. If any of the
original wire as supplied with the furnace must be replaced,
it must be replaced with wiring material having a tempera-
ture rating of at least 105° C. Any replacement wiring must
be copper conductor.
Before proceeding with electrical connections, ensure that
the supply voltage, frequency, and phase correspond to
furnace must be N.E.C. Class 1, and must comply with all