Vaillant Air Conditioners Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
Advertisements
E0
E0 error, unit will not start or stops immediately after power‑up
EEPROM / Configuration Data Error
E1
E1 error, unit stops cooling/heating and may restart repeatedly
High‑Pressure Protection / Overpressure Trip
E2
E2 error, unit stops and may show signs of evaporator icing or very low airflow
Evaporator Freeze Protection / Low Temperature Lockout
E3
E3 error, compressor stops shortly after starting, poor cooling
Low‑Pressure Protection / Refrigerant Undercharge
E4
E4 error, compressor stops, unit may blow warm air in cooling mode
Discharge Temperature High Protection
E5
E5 error, compressor does not start or stops quickly, humming noise from outdoor unit
Overcurrent / Compressor Overload Protection
E6
E6 error, indoor unit operates but no cooling or heating, compressor does not run
Compressor Start Failure / Inverter Drive Fault
E7
E7 error, indoor unit louver does not move or is stuck in one position
Louver Motor / Stepper Motor Fault
E8
E8 error, unit stops and may show signs of overheating in indoor unit
Indoor Fan Overload / Overheat Protection
E9
E9 error, unit stops and may show water leakage or abnormal defrost behavior
Condensate Overflow / Drain Pan Sensor Fault
F0
Indoor unit displays F0 and the air conditioner will not start cooling or heating
Indoor Ambient Temperature Sensor Failure
F1
Indoor unit shows F1 and stops operation shortly after startup
Indoor Coil (Evaporator) Temperature Sensor Failure
F2
F2 displayed, unit stops or runs only briefly, poor temperature control
Indoor Pipe / Liquid Line Temperature Sensor Fault
F3
F3 error, outdoor unit does not start or stops shortly after starting
Outdoor Ambient Temperature Sensor Failure
F4
F4 error, outdoor unit runs briefly then shuts down, poor heating performance
Outdoor Coil (Condenser) Temperature Sensor Failure
F5
F5 displayed, unit may stop or run with reduced capacity, defrost issues in heat pump mode
Outdoor Discharge / Compressor Outlet Temperature Sensor Fault
F6
F6 error, indoor unit stops and may flash LEDs, no cooling or heating
Indoor–Outdoor Communication Failure
F7
F7 error, indoor fan does not run or runs erratically
Indoor Fan Motor Feedback / Hall Sensor Fault
F8
F8 error, outdoor fan does not run or unit overheats and shuts down
Outdoor Fan Motor Fault
F9
F9 error, unit stops and may show abnormal temperature readings
Indoor Return Air / Auxiliary Temperature Sensor Fault
P0
P0 code, unit does not start compressor, only fan may run
Inverter Module Protection / DC Bus Voltage Fault
P1
P1 code, unit may start then stop, unstable operation
Indoor Voltage Protection / Supply Voltage Out of Range
P2
P2 code, compressor stops during operation, especially in heating mode
Defrost Protection / Outdoor Coil Temperature Abnormal
P3
P3 code, compressor speed limited, reduced capacity
Current Limit / Compressor Overload Control
P4
P4 code, unit stops or runs intermittently, especially in high ambient temperatures
Inverter Module Overheat Protection
Symptom
Indoor unit coil freezes into a block of ice during cooling
Evaporator Icing / Low Airflow or Low Charge
Symptom
Indoor unit display is blank but unit can still be controlled by remote
Display PCB / LED Board Failure
Symptom
Indoor unit display works but does not respond to remote control commands
Remote Receiver / IR Board Fault
Symptom
Indoor unit does not power on at all, no display or response to remote
No Power / Indoor Power Supply Failure
Symptom
Indoor unit emits unpleasant musty or moldy odor when starting
Biological Growth on Evaporator and Drain Pan
Symptom
Indoor unit fan does not run, but display and outdoor unit operate
Indoor Fan Motor or Capacitor Failure
Symptom
Indoor unit frequently turns on and off, room temperature fluctuates widely
Thermostat / Sensor Placement or Oversizing Issue
Symptom
Indoor unit leaks water from the front or bottom during cooling
Condensate Drain Blockage / Poor Drainage
Symptom
Indoor unit makes loud rattling or buzzing noises during operation
Mechanical Vibration / Loose Components
Symptom
Indoor unit runs but no cooling, air feels only slightly cooler than room temperature
Refrigerant Undercharge / Partial Loss of Charge
Symptom
Indoor unit runs but no heating in heat pump mode, blows cool or lukewarm air
Reversing Valve Stuck or Not Energized
Symptom
Outdoor unit makes loud grinding or squealing noise
Outdoor Fan Bearing Failure or Debris Contact
Symptom
Outdoor unit runs but indoor unit does not blow air (no airflow from vents)
Indoor Fan Control or Louver Closed
Symptom
Outdoor unit vibrates excessively and transmits noise into the building
Mounting / Anti‑Vibration Isolation Problem
Symptom
Unit powers on but compressor and outdoor unit do not start, only indoor fan runs
Control Signal Failure to Outdoor Unit
Symptom
Unit trips the circuit breaker immediately or shortly after starting
Electrical Short or Overcurrent
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E0 |
E0 error, unit will not start or stops immediately after power‑up
|
EEPROM / Configuration Data Error | View Details |
| E1 |
E1 error, unit stops cooling/heating and may restart repeatedly
|
High‑Pressure Protection / Overpressure Trip | View Details |
| E2 |
E2 error, unit stops and may show signs of evaporator icing or very low airflow
|
Evaporator Freeze Protection / Low Temperature Lockout | View Details |
| E3 |
E3 error, compressor stops shortly after starting, poor cooling
|
Low‑Pressure Protection / Refrigerant Undercharge | View Details |
| E4 |
E4 error, compressor stops, unit may blow warm air in cooling mode
|
Discharge Temperature High Protection | View Details |
| E5 |
E5 error, compressor does not start or stops quickly, humming noise from outdoor unit
|
Overcurrent / Compressor Overload Protection | View Details |
| E6 |
E6 error, indoor unit operates but no cooling or heating, compressor does not run
|
Compressor Start Failure / Inverter Drive Fault | View Details |
| E7 |
E7 error, indoor unit louver does not move or is stuck in one position
|
Louver Motor / Stepper Motor Fault | View Details |
| E8 |
E8 error, unit stops and may show signs of overheating in indoor unit
|
Indoor Fan Overload / Overheat Protection | View Details |
| E9 |
E9 error, unit stops and may show water leakage or abnormal defrost behavior
|
Condensate Overflow / Drain Pan Sensor Fault | View Details |
| F0 |
Indoor unit displays F0 and the air conditioner will not start cooling or heating
|
Indoor Ambient Temperature Sensor Failure | View Details |
| F1 |
Indoor unit shows F1 and stops operation shortly after startup
|
Indoor Coil (Evaporator) Temperature Sensor Failure | View Details |
| F2 |
F2 displayed, unit stops or runs only briefly, poor temperature control
|
Indoor Pipe / Liquid Line Temperature Sensor Fault | View Details |
| F3 |
F3 error, outdoor unit does not start or stops shortly after starting
|
Outdoor Ambient Temperature Sensor Failure | View Details |
| F4 |
F4 error, outdoor unit runs briefly then shuts down, poor heating performance
|
Outdoor Coil (Condenser) Temperature Sensor Failure | View Details |
| F5 |
F5 displayed, unit may stop or run with reduced capacity, defrost issues in heat pump mode
|
Outdoor Discharge / Compressor Outlet Temperature Sensor Fault | View Details |
| F6 |
F6 error, indoor unit stops and may flash LEDs, no cooling or heating
|
Indoor–Outdoor Communication Failure | View Details |
| F7 |
F7 error, indoor fan does not run or runs erratically
|
Indoor Fan Motor Feedback / Hall Sensor Fault | View Details |
| F8 |
F8 error, outdoor fan does not run or unit overheats and shuts down
|
Outdoor Fan Motor Fault | View Details |
| F9 |
F9 error, unit stops and may show abnormal temperature readings
|
Indoor Return Air / Auxiliary Temperature Sensor Fault | View Details |
| P0 |
P0 code, unit does not start compressor, only fan may run
|
Inverter Module Protection / DC Bus Voltage Fault | View Details |
| P1 |
P1 code, unit may start then stop, unstable operation
|
Indoor Voltage Protection / Supply Voltage Out of Range | View Details |
| P2 |
P2 code, compressor stops during operation, especially in heating mode
|
Defrost Protection / Outdoor Coil Temperature Abnormal | View Details |
| P3 |
P3 code, compressor speed limited, reduced capacity
|
Current Limit / Compressor Overload Control | View Details |
| P4 |
P4 code, unit stops or runs intermittently, especially in high ambient temperatures
|
Inverter Module Overheat Protection | View Details |
| – |
Indoor unit coil freezes into a block of ice during cooling
|
Evaporator Icing / Low Airflow or Low Charge | View Details |
| – |
Indoor unit display is blank but unit can still be controlled by remote
|
Display PCB / LED Board Failure | View Details |
| – |
Indoor unit display works but does not respond to remote control commands
|
Remote Receiver / IR Board Fault | View Details |
| – |
Indoor unit does not power on at all, no display or response to remote
|
No Power / Indoor Power Supply Failure | View Details |
| – |
Indoor unit emits unpleasant musty or moldy odor when starting
|
Biological Growth on Evaporator and Drain Pan | View Details |
| – |
Indoor unit fan does not run, but display and outdoor unit operate
|
Indoor Fan Motor or Capacitor Failure | View Details |
| – |
Indoor unit frequently turns on and off, room temperature fluctuates widely
|
Thermostat / Sensor Placement or Oversizing Issue | View Details |
| – |
Indoor unit leaks water from the front or bottom during cooling
|
Condensate Drain Blockage / Poor Drainage | View Details |
| – |
Indoor unit makes loud rattling or buzzing noises during operation
|
Mechanical Vibration / Loose Components | View Details |
| – |
Indoor unit runs but no cooling, air feels only slightly cooler than room temperature
|
Refrigerant Undercharge / Partial Loss of Charge | View Details |
| – |
Indoor unit runs but no heating in heat pump mode, blows cool or lukewarm air
|
Reversing Valve Stuck or Not Energized | View Details |
| – |
Outdoor unit makes loud grinding or squealing noise
|
Outdoor Fan Bearing Failure or Debris Contact | View Details |
| – |
Outdoor unit runs but indoor unit does not blow air (no airflow from vents)
|
Indoor Fan Control or Louver Closed | View Details |
| – |
Outdoor unit vibrates excessively and transmits noise into the building
|
Mounting / Anti‑Vibration Isolation Problem | View Details |
| – |
Unit powers on but compressor and outdoor unit do not start, only indoor fan runs
|
Control Signal Failure to Outdoor Unit | View Details |
| – |
Unit trips the circuit breaker immediately or shortly after starting
|
Electrical Short or Overcurrent | View Details |
No matching codes found
Advertisements