Lennox G40UH(X)

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PROBLEM 6: CONTROL SIGNALS LOW FLAME SENSE DURING HEATING MODE
Condition Possible Cause Corrective Action/Comments
6.0
− Unit operates correctly but the diag-
nostic lights flash low flame sense
code
6.1.1
Sensor rod is improperly located on
the burner.
ACTION 1 − Check the sensor rod for proper loca-
tion on the burner. Properly locate the sensor rod
or replace if rod cannot be located correctly.
code
.
LED#1−Slow Flash
LED#2−Fast Flash
6.1.2
Sensor rod is contaminated.
ACTION 1 − Check sensor rod for contamination
or coated surface. Clean the sensor rod with steel
wool or replace sensor. DO NOT USE SAND PA-
PER TO CLEAN ROD. SAND PAPER WILL
CONTRIBUTE TO THE CONTAMINATION
PROBLEM.
PROBLEM 7: INDOOR BLOWER FAILS TO OPERATE IN COOLING, HEATING, OR CONTINUOUS
FAN MODE
Condition Possible Cause Corrective Action/Comments
7.0
− Indoor blower fails to operate in
continuous fan, cooling, or heating
mode.
7.1.1
Miswiring of furnace or improper con-
nections at control or indoor blower
motor.
ACTION 1− Correct wiring and/or replace any
loose connections. Check for correct wiring and
loose connections.
7.1.2
120V is not being supplied to the in-
door air blower or blower motor fail-
ure.
ACTION 1 − Check for 120V at the various calls
for indoor blower by energizing "Y", "G", and "W"
individually on the low voltage terminal strip. Note
that when "W’ is energized, the blower is delayed
45 seconds. If there is 120V to each motor tap but
the blower does not operate, replace the motor.
7.1.3
Defective control board
ACTION 1 − If there is not 120V when "Y", "G", or
"W" is energized, replace the control.
7.1.4
Defective run capacitor
ACTION 1 − Replace capacitor
PROBLEM 8: RF STATIC DURING TIME FOR IGNITION
Condition Possible Cause Corrective Action/Comments
8.0
− AM radio interference.
8.1.2
Ignitor operation
ACTION 1 − Call Technical Support, Dallas.