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TROUBLESHOOTING
Table 26 — LED Error Code Service Analysis
LEGEND
PROBLEM CAUSE REMEDY
Hardware failure.
(LED OFF)
Loss of power to control module (IGC). Check 5- amp fuse on IGC, power to unit, 24-v circuit breaker,
and transformer. Units without a 24-v circuit breaker have an
internal overload in the 24-v transformer. If the overload trips,
allow 10 minutes for automatic reset.
Limit switch fault.
(LED 2 flashes)
High temperature limit switch is open. Check the operation of the indoor (evaporator) fan motor.
Ensure that the supply-air temperature rise is in accordance with
the range on the unit nameplate.
Flame sense fault.
(LED 3 flashes)
The IGC sensed flame that should not be
present.
Reset unit. If problem persists, replace control board.
4 consecutive limit switch trips.
(LED 4 flashes)
Inadequate airflow to unit. Check operation of indoor (evaporator) fan motor and that supply-air
temperature rise agrees with range on unit nameplate information.
Ignition lockout.
(LED 5 flashes)
Unit unsuccessfully attempted ignition for
15 minutes.
Check ignitor and flame sensor electrode spacing, gaps, etc.
Ensure that flame sense and ignition wires are properly termi-
nated. Verify that unit is obtaining proper amount of gas.
Induced-draft motor fault.
(LED 6 flashes)
IGC does not sense that induced-draft
motor is operating.
Check for proper voltage. If motor is operating, check the
speed sensor plug/IGC Terminal J2 connection. Proper
connection: PIN 1— White, PIN 2 — Red, PIN 3 — Black.
Rollout switch fault.
(LED 7 flashes)
Rollout switch has opened. Rollout switch will automatically reset, but IGC will continue to
lock out unit. Check gas valve operation. Ensure that induced-
draft blower wheel is properly secured to motor shaft. Reset unit
at unit disconnect.
Internal control fault.
(LED 8 flashes)
Microprocessor has sensed an error in
the software or hardware.
If error code is not cleared by resetting unit power, replace the
IGC.
Temporary 1 hour automatic reset
fault. (LED 9 flashes)
Stray radio frequency signals in ?? Processor will be reset after 1 hour.
IGC —
Integrated Gas Unit Controller
LED —
Light-Emitting Diode
If the IGC must be replaced, be sure to ground yourself to dissi-
pate any electrical charge that may be present before handling
new control board. The IGC is sensitive to static electricity and
may be damaged if the necessary precautions are not taken.
IMPORTANT: Refer to Table 28 — Heating Service Trouble-
shooting for additional troubleshooting information.