Table 41 — 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, |
(LED OFF) |
| transformer. Units without a |
|
| in the |
|
| reset. |
Fan ON/OFF Delay Modified | High limit switch opens during heat exchanger | Ensure unit is fired on rate and temperature rise is correct. |
(LED/FLASH) |
| |
| Limit switch opens within three minutes after | Ensure unit’s external static pressure is within application guidelines. |
|
| |
Limit Switch Fault. | High temperature limit switch is open. | Check the operation of the indoor (evaporator) fan motor. |
(LED 2 flashes) |
| Ensure that the |
|
| 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 |
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. |
IGC does not sense that | Check for proper voltage. If motor is operating, check the speed sensor | |
(LED 6 flashes) | motor is operating. | 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 lockout unit. |
(LED 7 flashes) |
| Check gas valve operation. Ensure that |
|
| erly 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. |
|
Internal Software Fault. | Internal Software Processor fault. | Fault code will automatically reset after one hour. Can be immediately |
(LED 9 flashes) |
| reset by resetting unit power supply. |
CAUTION: If the IGC must be replaced, be sure to ground yourself to dissipate 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 42 — Heating Service Analysis for additional troubleshooting analysis.
LEGEND
IGC — Integrated Gas Unit Controller
LED —
Table 42 — Heating Service Analysis
PROBLEM | CAUSE | REMEDY |
Burners Will Not Ignite. | Misaligned spark electrodes. | Check flame ignition and sensor electrode positioning. Adjust as needed. |
| No gas at main burners. | Check gas line for air, purge as necessary. After purging gas line of air, allow |
|
| gas to dissipate for at least 5 minutes before attempting to relight unit. |
|
| Check gas valve. |
| Water in gas line. | Drain water and install drip leg to trap water. |
| No power to furnace. | Check power supply, fuses, wiring, and circuit breaker. |
| No 24 v power supply to control circuit. | Check transformer. Transformers with internal overcurrent protection require a |
|
| cool down period before resetting. |
| Miswired or loose connections. | Check all wiring and wire nut connections. |
| Replace thermostat. | |
| Broken thermostat wires. | Run continuity check. Replace wires, if necessary. |
Inadequate Heating. | Dirty air filter. | Clean or replace filter as necessary. |
| Gas input to unit too low. | Check gas pressure at manifold. Clock gas meter for input. If too low, increase |
|
| manifold pressure, or replace with correct orifices. |
| Unit undersized for application. | Replace with proper unit or add additional unit. |
| Restricted airflow. | Clean filter, replace filter, or remove any restrictions. |
| Blower speed too low. | Use high speed tap, increase fan speed, or install optional blower, as suitable |
|
| for individual units. |
| Limit switch cycles main burners. | Check rotation of blower, thermostat heat anticipator settings, and temperature |
|
| rise of unit. Adjust as needed. |
| Too much outdoor air. | Adjust minimum position. |
|
| Check economizer operation. |
Poor Flame Characteristics. | Incomplete combustion (lack of combustion | Check all screws around flue outlets and burner compartment. Tighten as nec- |
| air) results in: | essary. |
| Aldehyde odors, CO, sooting flame, or floating | Cracked heat exchanger. |
| flame. |
|
| Overfired unit — reduce input, change orifices, or adjust gas line or manifold | |
|
| |
|
| pressure. |
|
| Check vent for restriction. Clean as necessary. |
|
| Check orifice to burner alignment. |
Burners Will Not Turn Off. | Unit is locked into Heating mode for a one | Wait until mandatory one minute time period has elapsed or re- |
| minute minimum. | set power to unit. |