Goodman AMH8 Service Instructions Manual page 37

PRODUCT DESIGN
• High-stage gas valve closes after five seconds; low-
stage gas valve remains open.
• Integrated control module monitors flame presence.
Gas valve will remain open only if flame is detected.
• Circulator blower is energized on low heat speed
following a fixed thirty second blower on delay. Elec-
tronic air cleaner terminals are energized with cir-
culator blower.
• Furnace is now operating in low-stage heating mode.
• Furnace operates; integrated control module moni-
tors safety circuits continuously.
• If low-stage delay period expires, control will shift
operation from low-stage heating mode operation
to high-stage heating mode operation. Control will
energize circulator blower high heat speed and high
stage gas valve.
• Furnace is now operating in high-stage heating
mode.
• R and W thermostat contacts open, completing the
call for heat.
• Induced draft blower is de-energized following a
fifteen second post purge.
• Circulator blower is de-energized following a heat
off delay period (selectable 100 or 150 seconds;
factory set at 150 seconds).
The circulator blower will continue to run at current
heat speed for the duration of the cool down pe-
riod.
• Furnace awaits the next call from thermostat.
C M
OOLING ODE
The normal operational sequence in cooling mode is as
follows:
• R and Y thermostat contacts close, initiating a call
for cool.
• Integrated control module performs safety circuit
checks.
• Outdoor fan and compressor are energized.
• Circulator blower is energized on cool speed fol-
lowing a fixed five second on delay. Electronic air
cleaner terminals are energized with circulator
blower.
• Furnace circulator blower and outdoor cooling unit
run, integrated control module monitors safety cir-
cuits continuously.
• R and Y thermostat contact open, completing the
call for cool.
• Outdoor fan and compressor are de-energized.
• Circulator blower is de-energized following a fixed
forty five second cool off delay period. Electronic
air cleaner terminals are de-energized.
• Furnace awaits the next call from thermostat.
F O M
AN NLY ODE
The normal operational sequence in fan only mode is as
follows:
• R and G thermostat contacts close, initiating a call
for fan.
• Integrated control module performs safety circuit
checks.
• Circulator blower is energized on low heat speed.
Electronic air cleaner terminals are energized.
• Circulator blower runs, integrated control module
monitors safety circuits continuously.
• R and G thermostat contacts open, completing the
call for fan.
• Circulator blower is de-energized. Electronic air
cleaner terminals are de-energized.
• Furnace awaits the next call from thermostat.
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