Place
thermostat
fan switch in
the ON
position.
Return fan
switch to
AUTO position.
Indoor Blower
Check
Does indoor
blower run at
HEAT speed?
YES
YES
NO
NO
YES
NO
YES
NO
YES
NO
Indoor blower
fault. Repair or
replace. Check
operation.
Is 24V
present at
control
terminals
G & C?
Is 120V
present at
control terminals
COOL & CIR
NEUTRAL?
Is 24V
present at
control
terminals
R & C?
Does LED
flash 1 time
when disconnect
is turned
ON?
Is 120V
present across
primary of control
transformer?
Is 24V
present across
secondary of
transformer?
Is 24V
present
across 12-pin
connector pins TH
& TR on the
control?
Is 120V
present at
control terminals
XFMR & XFMR
NEUTRAL?
Is 120V
present across
control terminals
LINE & LINE
NEUTRAL?
Repair wiring
from control to
thermostat. Check
operation.
Repair wiring
and/or plug
connection. Check
operation.
Replace
transformer. Check
operation.
Repair wiring to
transformer. Check
operation.
Correct 120V
power supply. Check
operation.
Replace control.
Check operation.
Replace control.
Check operation.
1A
1B
1E
1D
1C
1F
1I
1H
1G
1J
1K
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
CHART 1
WARNING
!
If diagnostic indicator (LED)
shows continuous flashing, turn
off gas supply at source before
disconnecting electrical power!
INTEGRATED FURNACE
CONTROL MODULE
TROUBLESHOOTING
GUIDE
www.white-rodgers.com
190
TECHNICAL
HELP
