Wolf Boilers Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
Advertisements
A01
Boiler does not ignite, display shows A01 lockout, red fault LED lit
Ignition Failure / No Flame Detection
A02
Boiler locks out with A02, burner starts then shuts down after a few seconds
Flame Loss During Operation
A03
Boiler shows A03 and shuts down, overheat symbol may be displayed
Safety Temperature Limiter (STB) Tripped / Overheat
A04
Display shows A04, boiler does not start, low pressure symbol may be lit
Low System Water Pressure
A05
Boiler displays A05; the fan runs, but the burner does not ignite or shuts down quickly.
Flue Gas / Air Pressure Fault
A06
Boiler displays A06; no heating or hot water, and the fan may not start.
Fan Fault / No Airflow Detected
A07
Boiler displays A07; heating stops, and the flow temperature rises rapidly.
Insufficient Circulation / Flow Temperature Rise Too Fast
A08
Boiler displays A08; the burner does not start, and domestic hot water and heating are unavailable.
Flow Temperature Sensor Fault (NTC Open/Short)
A09
Boiler displays A09; hot water temperature is unstable, or the boiler shuts down intermittently.
Return Temperature Sensor Fault (NTC Open/Short)
A10
Boiler displays A10; domestic hot water (DHW) is not available, or the temperature is incorrect.
DHW Temperature Sensor Fault
A11
Boiler displays A11; the burner does not start, and the control panel is unresponsive to heat demand.
Communication Fault Between Boiler PCB and Controller
A12
Boiler displays A12; burner output is limited, and heating is slow to reach the set temperature.
Modulation / Gas Valve Control Fault
A13
Boiler displays A13; the burner shuts down, and the flue gas temperature is too high.
Flue Gas Temperature Limit Exceeded
A14
Boiler displays A14; no ignition occurs, and the fan may run briefly then stop.
Air Pressure Switch Not Proving / Stuck
A15
Boiler displays A15, burner stops, condensate may be visible around the boiler.
Condensate Drain Blocked / Backflow Detected
A16
Boiler displays A16, burner output limited, system may be noisy.
Flow Sensor / Flow Switch Fault (Low or No Flow Detection)
A17
Boiler displays A17, burner stops, error appears after a long run time.
Return Temperature Too High / Delta-T Too Low
A18
Boiler displays A18, no response to room thermostat, heating remains off.
External Control / Thermostat Input Fault
A19
Boiler displays A19, display may flicker, random lockouts.
Mains Voltage / Power Supply Fault
A20
Boiler displays A20, burner does not start, safety chain open.
Safety Circuit Open (Limit Switch / Safety Chain Fault)
Symptom
Boiler flue terminal dripping water or staining the wall.
Condensate / Flue Drainage Issue
Symptom
Boiler frequently locks out during very cold weather; the external condensate pipe is icy.
Frozen Condensate Pipe
Symptom
Boiler frequently loses pressure and needs topping up every few days.
Chronic Pressure Loss
Symptom
Boiler leaking water from underneath the casing.
Internal Water Leak
Symptom
Boiler makes loud banging or knocking noises (kettling) during operation.
Heat Exchanger Kettling / Localised Boiling
Symptom
Boiler pressure rises rapidly when heating and may discharge water from the safety valve.
Over-Pressurisation Under Load
Symptom
Boiler room feels unusually hot; boiler casing very warm even when not firing.
Standby Overheating / Residual Heat Issue
Symptom
Boiler runs but radiators remain cold or only lukewarm.
Poor Heating Performance / No Circulation
Symptom
Boiler starts then shuts down after a few seconds without showing a specific error code.
Short Cycling / Unstable Combustion
Symptom
Boiler vibrates excessively and transmits noise through the building structure.
Mechanical Vibration / Mounting Fault
Symptom
Boiler will not start at all; no display or lights.
No Power / Dead Boiler
Symptom
Domestic hot water temperature fluctuates between hot and cold.
Unstable DHW Temperature Control
Symptom
No domestic hot water, but heating works normally.
DHW Priority / Diverter Fault
Symptom
Radiators get hot even when there is no call for heating.
Unwanted Heating / Valve Bypass
Symptom
Smell of burning or melted plastic from the boiler casing.
Overheating Electrical Component
Symptom
Strong smell of gas near the boiler.
Gas Leak in Boiler or Nearby Pipework
Symptom
The boiler display works but does not respond to room thermostat changes; heating stays on or off permanently.
Control / Thermostat Communication Issue
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| A01 |
Boiler does not ignite, display shows A01 lockout, red fault LED lit
|
Ignition Failure / No Flame Detection | View Details |
| A02 |
Boiler locks out with A02, burner starts then shuts down after a few seconds
|
Flame Loss During Operation | View Details |
| A03 |
Boiler shows A03 and shuts down, overheat symbol may be displayed
|
Safety Temperature Limiter (STB) Tripped / Overheat | View Details |
| A04 |
Display shows A04, boiler does not start, low pressure symbol may be lit
|
Low System Water Pressure | View Details |
| A05 |
Boiler displays A05; the fan runs, but the burner does not ignite or shuts down quickly.
|
Flue Gas / Air Pressure Fault | View Details |
| A06 |
Boiler displays A06; no heating or hot water, and the fan may not start.
|
Fan Fault / No Airflow Detected | View Details |
| A07 |
Boiler displays A07; heating stops, and the flow temperature rises rapidly.
|
Insufficient Circulation / Flow Temperature Rise Too Fast | View Details |
| A08 |
Boiler displays A08; the burner does not start, and domestic hot water and heating are unavailable.
|
Flow Temperature Sensor Fault (NTC Open/Short) | View Details |
| A09 |
Boiler displays A09; hot water temperature is unstable, or the boiler shuts down intermittently.
|
Return Temperature Sensor Fault (NTC Open/Short) | View Details |
| A10 |
Boiler displays A10; domestic hot water (DHW) is not available, or the temperature is incorrect.
|
DHW Temperature Sensor Fault | View Details |
| A11 |
Boiler displays A11; the burner does not start, and the control panel is unresponsive to heat demand.
|
Communication Fault Between Boiler PCB and Controller | View Details |
| A12 |
Boiler displays A12; burner output is limited, and heating is slow to reach the set temperature.
|
Modulation / Gas Valve Control Fault | View Details |
| A13 |
Boiler displays A13; the burner shuts down, and the flue gas temperature is too high.
|
Flue Gas Temperature Limit Exceeded | View Details |
| A14 |
Boiler displays A14; no ignition occurs, and the fan may run briefly then stop.
|
Air Pressure Switch Not Proving / Stuck | View Details |
| A15 |
Boiler displays A15, burner stops, condensate may be visible around the boiler.
|
Condensate Drain Blocked / Backflow Detected | View Details |
| A16 |
Boiler displays A16, burner output limited, system may be noisy.
|
Flow Sensor / Flow Switch Fault (Low or No Flow Detection) | View Details |
| A17 |
Boiler displays A17, burner stops, error appears after a long run time.
|
Return Temperature Too High / Delta-T Too Low | View Details |
| A18 |
Boiler displays A18, no response to room thermostat, heating remains off.
|
External Control / Thermostat Input Fault | View Details |
| A19 |
Boiler displays A19, display may flicker, random lockouts.
|
Mains Voltage / Power Supply Fault | View Details |
| A20 |
Boiler displays A20, burner does not start, safety chain open.
|
Safety Circuit Open (Limit Switch / Safety Chain Fault) | View Details |
| – |
Boiler flue terminal dripping water or staining the wall.
|
Condensate / Flue Drainage Issue | View Details |
| – |
Boiler frequently locks out during very cold weather; the external condensate pipe is icy.
|
Frozen Condensate Pipe | View Details |
| – |
Boiler frequently loses pressure and needs topping up every few days.
|
Chronic Pressure Loss | View Details |
| – |
Boiler leaking water from underneath the casing.
|
Internal Water Leak | View Details |
| – |
Boiler makes loud banging or knocking noises (kettling) during operation.
|
Heat Exchanger Kettling / Localised Boiling | View Details |
| – |
Boiler pressure rises rapidly when heating and may discharge water from the safety valve.
|
Over-Pressurisation Under Load | View Details |
| – |
Boiler room feels unusually hot; boiler casing very warm even when not firing.
|
Standby Overheating / Residual Heat Issue | View Details |
| – |
Boiler runs but radiators remain cold or only lukewarm.
|
Poor Heating Performance / No Circulation | View Details |
| – |
Boiler starts then shuts down after a few seconds without showing a specific error code.
|
Short Cycling / Unstable Combustion | View Details |
| – |
Boiler vibrates excessively and transmits noise through the building structure.
|
Mechanical Vibration / Mounting Fault | View Details |
| – |
Boiler will not start at all; no display or lights.
|
No Power / Dead Boiler | View Details |
| – |
Domestic hot water temperature fluctuates between hot and cold.
|
Unstable DHW Temperature Control | View Details |
| – |
No domestic hot water, but heating works normally.
|
DHW Priority / Diverter Fault | View Details |
| – |
Radiators get hot even when there is no call for heating.
|
Unwanted Heating / Valve Bypass | View Details |
| – |
Smell of burning or melted plastic from the boiler casing.
|
Overheating Electrical Component | View Details |
| – |
Strong smell of gas near the boiler.
|
Gas Leak in Boiler or Nearby Pipework | View Details |
| – |
The boiler display works but does not respond to room thermostat changes; heating stays on or off permanently.
|
Control / Thermostat Communication Issue | View Details |
No matching codes found
Advertisements