26 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 →
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-283-53 | Murelle PRO HE 25 HO ErP | 2015–2018 |
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Your boiler has detected that the exhaust gases are getting too hot or are not escaping correctly, causing the system to shut down for safety.
Your boiler has switched itself off because the water pressure inside the system is too low for it to run safely.
Your boiler has detected that there is too much water pressure in the system, which can cause the safety valve to leak or the unit to stop working.
Your boiler's temperature sensor for hot water is reporting a fault, meaning the system cannot accurately monitor or heat your tap water.
Your boiler has detected a problem with the internal temperature sensor that monitors the water leaving the unit, preventing it from heating up correctly.
Your boiler is failing to light the burner, meaning it cannot produce heat or hot water because the fuel isn't igniting.
Your boiler has likely overheated, causing a safety switch to trip and shut the system down to prevent damage.
Your boiler is struggling to detect a flame, which prevents it from firing up to provide heating or hot water.
Your boiler has stopped working because water is not moving around the system properly, which is preventing the unit from heating up safely.
Your boiler has detected an internal sensor issue or a configuration mismatch, which is preventing it from running properly.
Your boiler is unable to control its heat output correctly because a signal wire to the gas burner is broken or detached, causing the system to stop working as a safety precaution.
Your boiler has lost its connection to the component that controls the gas flow, meaning it cannot safely ignite or heat your home.
Your boiler has detected that the exhaust gases are too hot or the temperature sensor itself has failed, causing the system to shut down for safety.
Your boiler has detected a problem with the sensor that monitors exhaust gases, and it has shut down for safety purposes.
Your boiler has detected a communication problem with the fan, which means it cannot safely clear waste gases to start the ignition process.
Your boiler has detected that waste water cannot drain away properly, usually due to a blocked or frozen pipe outside.
Your boiler has locked you out because it was reset too many times in a row while trying to clear a persistent fault.
Your boiler has detected that the electricity supply coming into your home is at a dangerously low voltage, preventing it from running safely.
Your boiler has detected an issue with the electrical power supply frequency coming into your home and has shut down as a safety precaution.
Your boiler has tried to light several times but cannot maintain a steady flame, causing the system to lock out for safety.
Your boiler has detected that one of its control buttons is stuck or pressed for too long, preventing the system from working correctly.
Your boiler is having trouble communicating with your external thermostat or smart heating controller.
Your boiler has detected that a temperature sensor is loose or isn't seated correctly against the internal pipework, causing it to read temperatures inaccurately.
Your boiler has detected a flame at the wrong time during start-up, which usually means there is a problem with the air supply or the gas settings.
Your boiler is struggling to burn gas correctly, which is often caused by a temporary interruption in the fuel supply or an issue with the ignition system.
Your boiler has shut down because it cannot safely expel waste gases through the flue pipe, often due to an external blockage or a buildup of debris.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes