19 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Tap any card for details
Your boiler has detected an issue with the sensors that monitor the internal temperature, causing it to stop operating to keep your system safe.
Your boiler is struggling to send water through your radiators or taps because it has detected an issue with the sensor that measures the water temperature as it leaves the unit.
Your boiler has detected a problem with the temperature sensors, meaning it cannot accurately measure how hot the water is and has stopped working to keep you safe.
Your boiler has stopped working because it has detected that the water inside it has become dangerously overheated.
Your boiler has detected that the water pressure inside the system has dropped too low to operate safely.
Your boiler has detected that the water is not circulating properly through the system, often because the water has heated up too quickly or isn't moving away from the internal heat exchanger.
Your boiler has detected that the temperature of the exhaust gases leaving the flue is too high, causing it to shut down for safety reasons.
Your boiler has failed to ignite the flame needed to heat your water and has safely shut itself down as a precaution.
Your boiler has detected a problem with the internal fan that pushes exhaust gases out, meaning it has safely shut itself down to prevent unsafe operation.
Your boiler has lost track of how hot the water inside the heating system is because a temperature sensor has failed.
Your boiler's flue sensor is detecting a fault, meaning the system cannot accurately monitor the temperature of the exhaust gases, so it has safely shut down to prevent damage.
Your boiler is struggling to detect the temperature of the water it is trying to heat, so it has shut down to prevent overheating.
Your boiler has automatically shut down because it detected that the internal water temperature became dangerously high.
Your boiler has temporarily stopped working because the water pressure inside the system has dropped too low.
Your boiler has detected that water is not flowing properly around your heating system, so it has safely shut down to prevent overheating.
Your boiler has temporarily stopped working because it has detected that the exhaust gases coming from the flue are too hot.
Your boiler has temporarily stopped working because it cannot detect a steady flame, which usually points to an issue with your gas supply or the way the boiler is igniting.
Your boiler has stopped working because it cannot detect that the internal fan, which safely removes combustion gases, is operating properly.
Your boiler is struggling to get water moving around the system correctly before it attempts to fire up.
BoilerFaultCodes