TROUBLESHOOTING

TROUBLESHOOTING

Refer to Tables 30-36 for troubleshooting details.

Table 30 — LED Error Code Service Analysis

SYMPTOM

CAUSE

REMEDY

Hardware failure.

Loss of power to control module (IGC).

Check 5 amp fuse on IGC, power to unit, 24-v circuit breaker, and

(LED OFF)

 

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.

Fan ON/OFF delay modified

High limit switch opens during heat

Ensure unit is fired on rate and temperature rise is correct.

(LED/FLASH)

exchanger warm-up period before fan-on

 

 

delay expires.

 

 

Limit switch opens within three minutes

Ensure units’ external static pressure is within application guidelines.

 

after blower-off delay timing in Heating mode.

 

Limit switch fault.

High temperature limit switch is open.

Check the operation of the indoor (evaporator) fan motor.

(LED 2 flashes)

 

Ensure that the supply-air temperature rise is in accordance with

 

 

the range on the unit nameplate.

Flame sense fault.

The IGC sensed flame that should not be

Reset unit. If problem persists, replace control board.

(LED 3 flashes)

present.

 

4 consecutive limit

Inadequate airflow to unit.

Check operation of indoor (evaporator) fan motor and that supply-air

switch faults.

 

temperature rise agrees with range on unit nameplate information.

(LED 4 flashes)

 

 

Ignition lockout.

Unit unsuccessfully attempted ignition for

Check ignitor and flame sensor electrode spacing, gaps, etc.

(LED 5 flashes)

15 minutes.

Ensure that flame sense and ignition wires are properly

 

 

terminated. Verify that unit is obtaining proper amount of gas.

Induced-draft motor fault.

IGC does not sense that induced-draft

Check for proper voltage. If motor is operating, check the

(LED 6 flashes)

motor is operating.

speed sensor plug/IGC Terminal J2 connection. Proper

 

 

connection: PIN 1— White, PIN 2 — Red, PIN 3 — Black.

Rollout switch fault.

Rollout switch has opened.

Rollout switch will automatically reset, but IGC will continue to

(LED 7 flashes)

 

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.

Microprocessor has sensed an error in the

If error code is not cleared by resetting unit power, replace the IGC.

(LED 8 flashes)

software or hardware.

 

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 heating troubleshooting for additional heating section troubleshooting information.

LEGEND

IGC — Integrated Gas Unit Controller

LED — Light-Emitting Diode

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Carrier 48HJD005-007 specifications Troubleshooting, LED Error Code Service Analysis