Installation Instructions
55
T
ROUBLESHOOTING
 C
HART
Symptoms
Green 
LED Code
Amber
LED Code
Red
LED Code
Fault Description Check Cautions 
•Furnace fails to operate 
•Control board LED is off
•None •None •None
•Defective disconnect switch 
•defective door switch • No 
115 volt power •No 24 volt 
power
•Determine cause and restore 
proper high and low volt power 
supply 
•Confirm electrically safe 
condition before 
proceeding with repairs
•Furnace is waiting for a 
call
•Solid ON •None •None
•Furnace is not receiving a 
call 
•None Required
•Confirm electrically safe 
condition before 
proceeding with work
•Furnace fan only is 
running
•Rapid Flash •None •None
•Furnace is receiving a call for 
fan (24 volts on G terminal
•None Required
•Confirm electrically safe 
condition before 
proceeding with work
•Normal operation with 
low stage call for cooling 
(Ylo & G)
•One 
repeating 
flash
•None •None
•Normal operation with low 
stage call for cooling (Ylo & G)
•None Required
•Confirm electrically safe 
condition before 
proceeding with work
•Normal operation with 
high or single stage call 
for cooling (Y & G)
•Two 
repeating 
flashes
•None •None
•Normal operation with high 
or single stage call for cooling 
(Y & G)
•None Required
•Confirm electrically safe 
condition before 
proceeding with work
•Normal operation with 
low stage call for heat 
(W1)
•None
•One 
repeating 
flash
•None
•Normal operation with low 
stage call for heat (W1)
•None Required
•Confirm electrically safe 
condition before 
proceeding with work
•Normal operation with 
high or single stage call 
for heat 
•None
•Two 
repeating 
flashes
•None
•Normal operation with high 
or single stage call for heat 
•None Required
•Confirm electrically safe 
condition before 
proceeding with work
•Furnace does not 
operate, three Amber 
flashes on control board
•None
•Three 
repeating 
flashes
•None •W2 call present without W1
•Faulty thermostat or 
thermostat wiring or 
improperly connected 
thermostat wires
•Confirm electrically safe 
condition before 
proceeding with repairs
•Furnace does not 
operate, four Amber 
flashes on control board
•None
•Four 
repeating 
flashes
•None
•Ylo or Y call present without 
G
•Faulty thermostat or 
thermostat wiring or 
improperly connected 
thermostat wires
•Confirm electrically safe 
condition before 
proceeding with repairs
•Furnace does not 
operate, rapid Amber 
flashes on control board
•None •Rapid •None •Low flame sense current
•Dirty / coated flame rod, poor 
flame, improper gas pressure, 
poor flame sense wire or 
connections
•Clean flame rod with 
steel wool. Confirm 
electrically safe condition 
before proceeding with 
repairs
•Furnace does not 
operate, one Red flash 
on control board
•None •None
•One 
repeating 
flash
•Flame sensed when no 
flame should be present
•Gas valve stuck open, 
improper wiring to gas valve, 
shorted flame rod or wire
•Confirm electrical and 
gas safe conditions 
before proceeding with 
repairs
•Furnace does not 
operate, two Red 
flashes on control board, 
possible inducer 
operation
•None •None
•Two 
repeating 
flashes
•Pressure switch stuck closed
•Faulty pressure switch, 
pressure switch wires shorted, 
control board inducer relay 
stuck closed
•Confirm electrically safe 
condition before 
proceeding with repairs
•Furnace does not 
operate, three Red 
flashes on control board
•None •None
•Three 
repeating 
flashes
•Low fire pressure switch 
stuck open
•Faulty pressure switch, 
pressure switch or tubing or 
wiring / connection, control 
board inducer relay failed, vent 
pipe restriction / excessive 
elbows or length
•Confirm electrically safe 
condition before 
proceeding with repairs










