Worcester
Worcester Furnaces Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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A1
Boiler shows A1 and stops, often during or after heavy rain or freezing conditions, condensate may not be draining.
Condensate Drain Blocked / Pump Fault
A7
Boiler displays A7, hot water temperature is erratic or incorrect, particularly on combi models.
Hot Water Temperature Sensor Error
C6
Boiler shows C6, fan speed error, boiler may not ignite or may shut down shortly after starting.
Fan Speed / Hall Sensor Fault
C7
Boiler displays C7, indicating a fan not running or fan speed too low, no ignition.
Fan Not Running
CE
Boiler shows CE, communication error between user interface and main PCB, display may be blank or flicker.
Control PCB / Interface Communication Fault
D1
Boiler shows D1, often related to low system pressure or circulation issues, heating may not start.
Low Water Pressure / Circulation Fault
E1 224
Boiler shows E1 224, locks out shortly after ignition, sometimes with brief flame then shutdown.
Flame Loss During Operation
E1 227
Boiler displays E1 227, attempts to ignite but fails, then locks out. You may hear the fan run but no flame is established.
No Flame Signal After Ignition Attempt
E2
Boiler displays E2 and will not fire, may occur intermittently, often associated with temperature sensor issues.
Flow Temperature Sensor (NTC) Fault
E3
Boiler shows E3, may run briefly then shut down, often related to return temperature sensing.
Return Temperature Sensor (NTC) Fault
E5
Boiler displays E5, fan may not start or may run erratically, boiler will not ignite.
Fan / Air Pressure Fault
E6
Boiler shows E6, often associated with hot water temperature issues on combi models, water may run too hot or cold.
DHW Temperature Sensor (Hot Water NTC) Fault
E9
Boiler shows E9 and shuts down, may overheat quickly, flow pipe extremely hot, radiators may not heat evenly.
Overheat / Safety Temperature Limiter Trip
E9 224
Boiler intermittently overheats and shows E9 224, may be linked to pump or flow issues rather than pure sensor failure.
Overheat Due to Poor Circulation
EA
Boiler locks out with EA on display, burner does not ignite, you may hear clicking from the gas valve or ignition but no flame is established.
Ignition Failure / Flame Not Detected
F0
Boiler displays F0, internal fault, may be associated with sensor or PCB issues, boiler may lock out.
General Internal Fault / Sensor Range Error
F1
Boiler shows F1, often indicating a flow sensor or pump-related issue, heating may be weak or non-existent.
Flow Switch / Flow Sensor Fault
F7
Boiler displays F7, often related to flue gas sensor or temperature sensor issues on condensing models.
Flue Gas Temperature Sensor Fault
H07
Boiler shows H07, often associated with low system pressure or water content, heating may not start.
Low Water Content / Pressure Warning
U9
Boiler displays U9, indicating a communication or configuration error, may occur after PCB replacement.
Configuration / Parameter Error
Symptom
Boiler casing or nearby walls show signs of soot or black staining, possible smell of exhaust gases.
Incomplete Combustion / Flue Gas Spillage
Symptom
Boiler cycles on and off rapidly, radiators only warm at the bottom, some rooms never reach set temperature.
Poor System Balancing / Sludge Restriction
Symptom
Boiler emits a burning smell or plastic smell when running, possibly with slight smoke from casing vents.
Overheating Electrical Component
Symptom
Boiler fan runs but there is no ignition and no error code, boiler eventually times out.
Ignition Sequence Interruption
Symptom
Boiler flue terminal drips water or white staining appears on the wall below the flue.
Condensate / Flue Joint Leakage
Symptom
Boiler frequently loses pressure, pressure gauge drops to zero over hours or days, requiring regular top-ups.
Chronic Pressure Loss
Symptom
Boiler ignites with a loud bang or pop, sometimes shaking the flue or casing.
Delayed Ignition
Symptom
Boiler is very noisy during operation, with whistling, droning, or rumbling sounds from the combustion chamber.
Combustion Noise / Incorrect Gas-Air Ratio
Symptom
Boiler leaking water from underneath the casing or from pipe connections, puddles forming below the Worcester furnace/boiler.
Internal Water Leak
Symptom
Boiler makes loud banging or kettling noises when heating, especially as it starts or stops, pipes may vibrate.
Kettling / Localised Boiling in Heat Exchanger
Symptom
Boiler runs but hot water temperature fluctuates significantly during a shower, alternating hot and cold.
Inconsistent DHW Temperature Control
Symptom
Boiler runs but radiators do not get hot, or only partially heat, while hot water may still work on combi models.
Central Heating Circulation Failure
Symptom
Boiler runs but room temperature overshoots the thermostat setting, house becomes too hot.
Control Overshoot / Thermostat Fault
Symptom
Boiler starts then shuts down after a few seconds, radiators barely warm, no error code displayed.
Short Cycling Due to Control or Sensor Issues
Symptom
Boiler will not start at all, no lights or display, appears completely dead.
No Power / Dead Appliance
Symptom
Radiators get hot but domestic hot water is lukewarm or cold on a Worcester combi boiler.
DHW Priority / Plate Heat Exchanger Flow Fault
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| A1 |
Boiler shows A1 and stops, often during or after heavy rain or freezing conditions, condensate may not be draining.
|
Condensate Drain Blocked / Pump Fault | View Details |
| A7 |
Boiler displays A7, hot water temperature is erratic or incorrect, particularly on combi models.
|
Hot Water Temperature Sensor Error | View Details |
| C6 |
Boiler shows C6, fan speed error, boiler may not ignite or may shut down shortly after starting.
|
Fan Speed / Hall Sensor Fault | View Details |
| C7 |
Boiler displays C7, indicating a fan not running or fan speed too low, no ignition.
|
Fan Not Running | View Details |
| CE |
Boiler shows CE, communication error between user interface and main PCB, display may be blank or flicker.
|
Control PCB / Interface Communication Fault | View Details |
| D1 |
Boiler shows D1, often related to low system pressure or circulation issues, heating may not start.
|
Low Water Pressure / Circulation Fault | View Details |
| E1 224 |
Boiler shows E1 224, locks out shortly after ignition, sometimes with brief flame then shutdown.
|
Flame Loss During Operation | View Details |
| E1 227 |
Boiler displays E1 227, attempts to ignite but fails, then locks out. You may hear the fan run but no flame is established.
|
No Flame Signal After Ignition Attempt | View Details |
| E2 |
Boiler displays E2 and will not fire, may occur intermittently, often associated with temperature sensor issues.
|
Flow Temperature Sensor (NTC) Fault | View Details |
| E3 |
Boiler shows E3, may run briefly then shut down, often related to return temperature sensing.
|
Return Temperature Sensor (NTC) Fault | View Details |
| E5 |
Boiler displays E5, fan may not start or may run erratically, boiler will not ignite.
|
Fan / Air Pressure Fault | View Details |
| E6 |
Boiler shows E6, often associated with hot water temperature issues on combi models, water may run too hot or cold.
|
DHW Temperature Sensor (Hot Water NTC) Fault | View Details |
| E9 |
Boiler shows E9 and shuts down, may overheat quickly, flow pipe extremely hot, radiators may not heat evenly.
|
Overheat / Safety Temperature Limiter Trip | View Details |
| E9 224 |
Boiler intermittently overheats and shows E9 224, may be linked to pump or flow issues rather than pure sensor failure.
|
Overheat Due to Poor Circulation | View Details |
| EA |
Boiler locks out with EA on display, burner does not ignite, you may hear clicking from the gas valve or ignition but no flame is established.
|
Ignition Failure / Flame Not Detected | View Details |
| F0 |
Boiler displays F0, internal fault, may be associated with sensor or PCB issues, boiler may lock out.
|
General Internal Fault / Sensor Range Error | View Details |
| F1 |
Boiler shows F1, often indicating a flow sensor or pump-related issue, heating may be weak or non-existent.
|
Flow Switch / Flow Sensor Fault | View Details |
| F7 |
Boiler displays F7, often related to flue gas sensor or temperature sensor issues on condensing models.
|
Flue Gas Temperature Sensor Fault | View Details |
| H07 |
Boiler shows H07, often associated with low system pressure or water content, heating may not start.
|
Low Water Content / Pressure Warning | View Details |
| U9 |
Boiler displays U9, indicating a communication or configuration error, may occur after PCB replacement.
|
Configuration / Parameter Error | View Details |
| – |
Boiler casing or nearby walls show signs of soot or black staining, possible smell of exhaust gases.
|
Incomplete Combustion / Flue Gas Spillage | View Details |
| – |
Boiler cycles on and off rapidly, radiators only warm at the bottom, some rooms never reach set temperature.
|
Poor System Balancing / Sludge Restriction | View Details |
| – |
Boiler emits a burning smell or plastic smell when running, possibly with slight smoke from casing vents.
|
Overheating Electrical Component | View Details |
| – |
Boiler fan runs but there is no ignition and no error code, boiler eventually times out.
|
Ignition Sequence Interruption | View Details |
| – |
Boiler flue terminal drips water or white staining appears on the wall below the flue.
|
Condensate / Flue Joint Leakage | View Details |
| – |
Boiler frequently loses pressure, pressure gauge drops to zero over hours or days, requiring regular top-ups.
|
Chronic Pressure Loss | View Details |
| – |
Boiler ignites with a loud bang or pop, sometimes shaking the flue or casing.
|
Delayed Ignition | View Details |
| – |
Boiler is very noisy during operation, with whistling, droning, or rumbling sounds from the combustion chamber.
|
Combustion Noise / Incorrect Gas-Air Ratio | View Details |
| – |
Boiler leaking water from underneath the casing or from pipe connections, puddles forming below the Worcester furnace/boiler.
|
Internal Water Leak | View Details |
| – |
Boiler makes loud banging or kettling noises when heating, especially as it starts or stops, pipes may vibrate.
|
Kettling / Localised Boiling in Heat Exchanger | View Details |
| – |
Boiler runs but hot water temperature fluctuates significantly during a shower, alternating hot and cold.
|
Inconsistent DHW Temperature Control | View Details |
| – |
Boiler runs but radiators do not get hot, or only partially heat, while hot water may still work on combi models.
|
Central Heating Circulation Failure | View Details |
| – |
Boiler runs but room temperature overshoots the thermostat setting, house becomes too hot.
|
Control Overshoot / Thermostat Fault | View Details |
| – |
Boiler starts then shuts down after a few seconds, radiators barely warm, no error code displayed.
|
Short Cycling Due to Control or Sensor Issues | View Details |
| – |
Boiler will not start at all, no lights or display, appears completely dead.
|
No Power / Dead Appliance | View Details |
| – |
Radiators get hot but domestic hot water is lukewarm or cold on a Worcester combi boiler.
|
DHW Priority / Plate Heat Exchanger Flow Fault | View Details |
No matching codes found
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