25 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Suprima
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
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Your boiler has stopped working because it failed to ignite or got too hot, and it now needs a manual reset to try and start again.
Your boiler has detected an internal issue and has safely shut itself down to prevent damage, meaning you currently have no heating or hot water until it is reset or repaired.
Your boiler has shut itself down for safety because it failed to light or detected an internal problem.
Your boiler has stopped working and entered a safety shutdown mode, meaning it will not provide heating or hot water until it is reset or repaired.
Your boiler has detected a internal problem and has safely switched itself off to prevent potential damage or unsafe operation.
Your boiler has detected that the electrical supply is incorrectly connected and is refusing to start as a safety precaution.
Your boiler has temporarily paused its operation because it has detected a minor inconsistency in its internal readings, such as water pressure or temperature.
Your boiler is briefly pausing itself to prevent the system from turning on and off too frequently, which helps protect the internal parts from unnecessary wear.
Your boiler has detected a communication failure with a internal safety sensor, causing it to shut down to prevent unsafe operation.
Your boiler has detected that it is becoming dangerously hot inside its outer shell and has switched itself off to prevent damage or fire risk.
Your boiler's internal computer brain has developed a critical error and is now unable to control the heating or hot water system safely.
Your boiler has no electrical power, meaning the controls and display are completely dead.
Your boiler has detected that there is not enough water inside it to operate safely, so it has shut down to prevent internal damage.
Your boiler has detected a faulty internal safety sensor which forces the system to shut down to prevent damage.
Your boiler has stopped working because the internal fan, which safely clears exhaust gases, isn't spinning at the correct speed.
Your boiler is trying to start but the flame is cutting out immediately, which means it cannot safely keep the heating or hot water running.
The boiler is failing to register that water is moving through the pipes, so it has stopped heating to protect itself from overheating.
Your boiler has stopped working for safety reasons because it detected an internal fault and has shut itself down to prevent damage.
Your boiler has detected trapped air inside the system, which is preventing water from circulating properly and causing it to shut down to prevent damage from overheating.
Your boiler has lost its ability to measure the temperature of the water returning to it, so it has shut down to prevent potential damage.
Your boiler's temperature sensors are giving conflicting readings, which is causing the system to stop working reliably to prevent overheating.
Your boiler is struggling to accurately measure the temperature of the water flowing through it, so it has shut down as a precaution to prevent overheating.
Your boiler's internal thermometer is sending back unreliable information, so it has stopped working to prevent potential overheating or damage.
Your boiler has detected an electrical fault with the sensor that detects the flame, causing it to shut down for safety reasons.
Your boiler has detected an electrical wiring error where the power wires appear to be connected incorrectly, which is a significant safety risk.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes