41
TROUBLESHOOTING CHART
Symptom
LED Status
Fault Description
Corrective Actions
Induced draft blower and
circulator blower runs
continuously
No furnace operation
Flame sensed with no call for
heat
Short to ground in flame sense
circuit
Lingering burner flame
Slow closing gas valve
Correct short at flame sensor or in flame sensor
wiring
Check for lingering or lazy flame
Verify proper operation of gas valve
No furnace operation
Open fuse
Short in low voltage wiring
Replace fuse
Locate and correct short in low voltage wiring
Normal furnace operation
Flame sense micro amp signal is
low
Flame sensor is coated/oxidized
Flame sensor incorrectly
positioned in burner fame
Lazy burner flame due to
improper gas pressure or
combustion air
Clean flame sensor if coated or oxidized
Inspect for proper flame sensor alignment
Check inlet air piping for blockage, proper length,
elbows, and termination
Compare current gas pressure to rating plate and
adjust as needed
Furnace fails to operate
Problem with igniter circuit
Improperly connected or shorted
igniter
Poor unit ground
Igniter relay fault on integrated
control module
Check and correct wiring from integrated control
module to igniter
Diagnose and replace shorted igniter as needed
Verify and correct unit ground wiring if needed
Check igniter output from control, replace if
necessary
Furnace fails to operate
Polarity of 115 volt AC is
reversed
Poor unit ground
Correct polarity, check and correct wiring if
necessary
Verify proper ground, correct if necessary
Furnace fails to operate
Gas valve is not energized when
it should be
External Gas Valve Error
Check Wiring in gas valve circuit
Replace integrated control board
Furnace fails to operate
Gas valve is energized when it
should not be
Internal Gas Valve Error
Check wiring in gas valve circuit
Replace integrated control board
Furnace fails to operate
Aux limit switch open (blower
compartment)
Ch
eck filters and ductwork for blockage, clean
filters or remove obstruction
Ch
eck filters and ductwork for blockage, clean
filters or remove obstruction
Furnace fails to operate
Aux switch (condensate switch)
open
Check circulator blower speed and performance,
correct speed or replace blower motor if necessary
Tighten or correct wiring connection
Check evaporator drain pan, trap, piping
Fault Code Recall
Accessing the furnace’s diagnostic menu provides access to the last six faults detected by the furnace. Faults are stored
most recent to least recent, Any consecutively repeated fault is stored a maximum of three times.
EXAMPLE:
A clogged
return air filter causes the furnace limit to trip repeatedly. The control will only store this fault the first three consecutive
times the fault occurs.
NOTE: It is highly recommended that the fault history be cleared when performing
maintenance or servicing the furnace.
