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Symptoms
Possible Cause
Check/Remedies
17. System starts up, cycles four
Condensation in molex plug
Replace igniter and/or repair wiring
times and locks out
(continued)
Igniter harness plug loose
Replace igniter and/or repair wiring
or wires damaged
Malfunctioning integrated furnace
Test and replace as necessary
control (IFC)
Improper unit ground
Check/repair ground connection
Igniter won't sense flame
Add Remote Flame Sensor,
AS-58494-01
18.
Blower (only) runs continuously
Thermostat fan setting in "ON" position Set to automatic position
Malfunctioning integrated fan
Test and replace board
control board
if necessary
19. Inducer fan (only) runs
Pressure switch open
Refer to "Pressure Switch"
checkout (#21)
20.
Blower and inducer fan
LimiVsafety control switch is open
Check wiring and test all
run continuously
limiVsafety controls
21.
Pressure switch fails to close Leaking mounting gasket
Clean gasket
areaand
of inducer fan
apply a new gasket
(Refer to Pressure Switch section
Faulty switch
Jumper pressure switch - if unit
for correct settings, page 89)
does not operate, determine cause:
if unit operates, replace the switch
Blocked vent pipe
Check and clear blockage
Hole in heat exchanger
Replace heat exchanger
121
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