Heil
Heil Air Conditioners Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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C1
Heil outdoor unit LED flashes C1; compressor fails to start reliably.
Compressor Start Circuit Fault
C2
Heil outdoor unit LED flashes C2; compressor runs briefly then trips.
Compressor Overcurrent / Locked Rotor
E1
Outdoor Heil air conditioner will not run; the thermostat shows an E1 communication error between the indoor and outdoor unit.
Indoor-Outdoor Communication Fault
E2
Heil air conditioner runs briefly, then shuts down; the thermostat or diagnostic LED indicates an E2 high-pressure fault.
High-Pressure Switch Trip
E3
Heil outdoor unit will not start; diagnostics indicate a low-pressure or loss-of-charge fault.
Low-Pressure Switch Trip / Loss of Refrigerant
E4
Heil air conditioner shuts down on very hot days; diagnostics indicate a discharge temperature or compressor overheat fault.
Compressor Overheat / Discharge Temperature High
E5
Heil communicating thermostat shows E5; the outdoor unit does not respond to cooling calls.
Outdoor Unit Not Responding / Control Board Fault
E6
Heil communicating system shows E6; the indoor blower runs, but the outdoor unit does not start.
Compressor Start Failure / Contactor or Capacitor Fault
E7
Heil air conditioner intermittently shuts off; thermostat or board displays E7 sensor fault.
Temperature Sensor / Thermistor Fault
E8
Heil ductless or small split AC displays E8 and stops cooling.
Indoor Fan Motor or Fan Feedback Fault
E9
Heil air conditioner displays E9; unit may run with poor performance or shut down.
EEPROM / Control Board Memory Error
F1
Heil communicating thermostat displays F1 indoor unit fault; cooling demand not satisfied.
Indoor Blower or Indoor Control Fault
F2
Heil communicating thermostat displays F2 outdoor unit fault; indoor blower runs but no cooling.
Outdoor Unit Lockout
F3
Heil thermostat displays F3; system cycles erratically or not at all.
Thermostat Sensor / Internal Fault
HPS
Heil outdoor unit LED indicates HPS; unit shuts down shortly after starting.
High-Pressure Switch Open
LPS
Heil outdoor unit LED indicates LPS; compressor will not run.
Low-Pressure Switch Open
OF
Heil thermostat or display shows 'OF' or 'OFF', and the outdoor unit does not run.
System Off / Lockout or Safety Open
Symptom
Heil air conditioner causes water to drip from the supply vents.
Excessive Humidity / Sweating Ducts
Symptom
Heil air conditioner emits a burning or electrical smell when running
Electrical Overheating
Symptom
Heil air conditioner frequently freezes up; ice forms on the indoor coil or suction line
Evaporator Coil Icing
Symptom
Heil air conditioner indoor coil rusted or leaking refrigerant
Evaporator Coil Leak
Symptom
Heil air conditioner indoor unit is very loud with whistling or roaring at vents
Airflow / Duct Noise Issue
Symptom
Heil air conditioner leaks water around the indoor unit or from the ceiling.
Condensate Drain Clog
Symptom
Heil air conditioner makes a loud buzzing or humming sound at the outdoor unit, but the fan and compressor do not start.
Failed Run Capacitor
Symptom
Heil air conditioner outdoor coil is physically damaged or flattened in areas
Condenser Coil Damage
Symptom
Heil air conditioner outdoor unit fan runs backwards or at incorrect speed after motor replacement
Incorrect Replacement Fan Motor Wiring
Symptom
Heil air conditioner outdoor unit fan starts then stops after a few seconds
Intermittent Fan Operation
Symptom
Heil air conditioner outdoor unit will not start at all; the indoor blower runs and the thermostat calls for cooling.
No Power to Outdoor Unit
Symptom
Heil air conditioner produces a musty or moldy odor from the vents
Biological Growth in Coil or Ducts
Symptom
Heil air conditioner runs but does not cool well; supply air is only slightly cooler than room temperature.
Reduced Cooling Capacity
Symptom
Heil air conditioner runs continuously and rarely shuts off, even when setpoint is reached
Continuous Operation / Control or Capacity Issue
Symptom
Heil air conditioner short cycles, turning on and off every few minutes.
Short Cycling
Symptom
Heil air conditioner thermostat display is blank and system does not run
Loss of 24V Control Power
Symptom
Heil air conditioner trips the breaker when starting or shortly after
Overcurrent / Short Circuit
Symptom
Heil air conditioner vibrates excessively and is loud inside the house
Vibration / Installation Issue
Symptom
Heil air conditioner will not start after a power outage
Post-Outage Lockout / Brownout Damage
Symptom
Heil outdoor fan runs but the compressor does not; there is no cooling inside.
Compressor Not Starting
Symptom
Heil outdoor unit is extremely noisy, with rattling or grinding sounds.
Mechanical Noise / Fan or Mounting Issue
Symptom
Heil outdoor unit runs but the indoor blower does not; the coil may freeze, and little or no air comes from the vents.
Indoor Blower Failure
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| C1 |
Heil outdoor unit LED flashes C1; compressor fails to start reliably.
|
Compressor Start Circuit Fault | View Details |
| C2 |
Heil outdoor unit LED flashes C2; compressor runs briefly then trips.
|
Compressor Overcurrent / Locked Rotor | View Details |
| E1 |
Outdoor Heil air conditioner will not run; the thermostat shows an E1 communication error between the indoor and outdoor unit.
|
Indoor-Outdoor Communication Fault | View Details |
| E2 |
Heil air conditioner runs briefly, then shuts down; the thermostat or diagnostic LED indicates an E2 high-pressure fault.
|
High-Pressure Switch Trip | View Details |
| E3 |
Heil outdoor unit will not start; diagnostics indicate a low-pressure or loss-of-charge fault.
|
Low-Pressure Switch Trip / Loss of Refrigerant | View Details |
| E4 |
Heil air conditioner shuts down on very hot days; diagnostics indicate a discharge temperature or compressor overheat fault.
|
Compressor Overheat / Discharge Temperature High | View Details |
| E5 |
Heil communicating thermostat shows E5; the outdoor unit does not respond to cooling calls.
|
Outdoor Unit Not Responding / Control Board Fault | View Details |
| E6 |
Heil communicating system shows E6; the indoor blower runs, but the outdoor unit does not start.
|
Compressor Start Failure / Contactor or Capacitor Fault | View Details |
| E7 |
Heil air conditioner intermittently shuts off; thermostat or board displays E7 sensor fault.
|
Temperature Sensor / Thermistor Fault | View Details |
| E8 |
Heil ductless or small split AC displays E8 and stops cooling.
|
Indoor Fan Motor or Fan Feedback Fault | View Details |
| E9 |
Heil air conditioner displays E9; unit may run with poor performance or shut down.
|
EEPROM / Control Board Memory Error | View Details |
| F1 |
Heil communicating thermostat displays F1 indoor unit fault; cooling demand not satisfied.
|
Indoor Blower or Indoor Control Fault | View Details |
| F2 |
Heil communicating thermostat displays F2 outdoor unit fault; indoor blower runs but no cooling.
|
Outdoor Unit Lockout | View Details |
| F3 |
Heil thermostat displays F3; system cycles erratically or not at all.
|
Thermostat Sensor / Internal Fault | View Details |
| HPS |
Heil outdoor unit LED indicates HPS; unit shuts down shortly after starting.
|
High-Pressure Switch Open | View Details |
| LPS |
Heil outdoor unit LED indicates LPS; compressor will not run.
|
Low-Pressure Switch Open | View Details |
| OF |
Heil thermostat or display shows 'OF' or 'OFF', and the outdoor unit does not run.
|
System Off / Lockout or Safety Open | View Details |
| – |
Heil air conditioner causes water to drip from the supply vents.
|
Excessive Humidity / Sweating Ducts | View Details |
| – |
Heil air conditioner emits a burning or electrical smell when running
|
Electrical Overheating | View Details |
| – |
Heil air conditioner frequently freezes up; ice forms on the indoor coil or suction line
|
Evaporator Coil Icing | View Details |
| – |
Heil air conditioner indoor coil rusted or leaking refrigerant
|
Evaporator Coil Leak | View Details |
| – |
Heil air conditioner indoor unit is very loud with whistling or roaring at vents
|
Airflow / Duct Noise Issue | View Details |
| – |
Heil air conditioner leaks water around the indoor unit or from the ceiling.
|
Condensate Drain Clog | View Details |
| – |
Heil air conditioner makes a loud buzzing or humming sound at the outdoor unit, but the fan and compressor do not start.
|
Failed Run Capacitor | View Details |
| – |
Heil air conditioner outdoor coil is physically damaged or flattened in areas
|
Condenser Coil Damage | View Details |
| – |
Heil air conditioner outdoor unit fan runs backwards or at incorrect speed after motor replacement
|
Incorrect Replacement Fan Motor Wiring | View Details |
| – |
Heil air conditioner outdoor unit fan starts then stops after a few seconds
|
Intermittent Fan Operation | View Details |
| – |
Heil air conditioner outdoor unit will not start at all; the indoor blower runs and the thermostat calls for cooling.
|
No Power to Outdoor Unit | View Details |
| – |
Heil air conditioner produces a musty or moldy odor from the vents
|
Biological Growth in Coil or Ducts | View Details |
| – |
Heil air conditioner runs but does not cool well; supply air is only slightly cooler than room temperature.
|
Reduced Cooling Capacity | View Details |
| – |
Heil air conditioner runs continuously and rarely shuts off, even when setpoint is reached
|
Continuous Operation / Control or Capacity Issue | View Details |
| – |
Heil air conditioner short cycles, turning on and off every few minutes.
|
Short Cycling | View Details |
| – |
Heil air conditioner thermostat display is blank and system does not run
|
Loss of 24V Control Power | View Details |
| – |
Heil air conditioner trips the breaker when starting or shortly after
|
Overcurrent / Short Circuit | View Details |
| – |
Heil air conditioner vibrates excessively and is loud inside the house
|
Vibration / Installation Issue | View Details |
| – |
Heil air conditioner will not start after a power outage
|
Post-Outage Lockout / Brownout Damage | View Details |
| – |
Heil outdoor fan runs but the compressor does not; there is no cooling inside.
|
Compressor Not Starting | View Details |
| – |
Heil outdoor unit is extremely noisy, with rattling or grinding sounds.
|
Mechanical Noise / Fan or Mounting Issue | View Details |
| – |
Heil outdoor unit runs but the indoor blower does not; the coil may freeze, and little or no air comes from the vents.
|
Indoor Blower Failure | View Details |
No matching codes found
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