18
TROUBLESHOOTING
If the unit does not operate in the cooling mode, check the
following:
• Is the thermostat operating properly?
• Is the blower compartment doors in place?
• Is the furnace disconnect closed?
• Has the circuit breaker tripped or did any of the control board
fuses burn open? NOTE: There are 2 fuses, one on the
control board (3-amp) and one in a fuse holder (1.5-amp)
to the right of the control board.
• Is the gas turned on?
• Is the gas turned on?
• Are any manual reset switches open?
• Is the filter dirty or plugged?
• Is the flame sensor coated? (Remove and clean with steel
wool. New gasket is required) See Cleaning of Flame Sensor
sectionon page 17.
• Are all the LED’s on the furnace control board constantly
ON? If not, refer to Table 3 or the wiring diagram (Figure
12 (page 24)) to determine fault condition.
IMPORTANT NOTE: The furnace will lock out after 5 failed
attempts for ignition and will try again every hour if the call
for heat remains.
• If the inducer blower is operating and items above have been
verified, check the limit switch circuit and reset if necessary.
See Figure 14 (page 29) for component location.
• If the furnace operates when the limit switch circuit is reset,
contact a qualified service technician to identify and repair
the problem.
• If the furnace still doesn’t operate, check the flame roll-out
switch and reset if necessary. See Figure 14 for component
location.
• If the furnace operates when the flame rollout switch is reset,
contact a qualified service technician to identify and repair
the problem.
Table 3. Diagnostic Codes
DIAGNOSTIC DESCRIPTION GREEN LED RED LED
Control Fault (No Power) Off Off
L1/Neutral Polarity Fault Flash Flash
1 Hour Lockout Alternating Flash
Normal Operation On On
Pressure Switch Closed Fault On Flash
Pressure Switch Open Fault Flash On
Open Limit Switch Fault Flash Off
DIAGNOSTIC DESCRIPTION YELLOW LED
Low Flame Sensor Signal Continuous Flash
Flame Present On