31 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has detected that it is getting too hot and has automatically shut down to prevent damage to its internal systems.
Your boiler has detected that there is not enough water flowing through the system to keep it running safely.
Your boiler has stopped working because the water isn't flowing properly through the system.
Your boiler has detected that water is not flowing properly through the system, which can cause it to overheat and shut down to protect itself.
Your boiler has failed to ignite the burner properly and has locked out for safety.
Your boiler has shut down because the water pressure inside the system is too low to operate safely.
Your boiler has detected that the water pressure inside the system is too low to run safely, and it needs you to top it up using the filling loop.
Your boiler has too much water inside its system, causing it to shut down to prevent damage from high pressure.
Your boiler has stopped working because it can no longer accurately read the temperature of the water circulating through your radiators.
Your boiler has lost the ability to read the temperature of the water returning to it from your radiators, so it has shut down to prevent potential damage.
Your boiler is having trouble communicating with the outdoor weather sensor, which helps it decide how hard to work based on the outside temperature.
Your boiler has detected that the external temperature safety switch—typically used for underfloor heating—is triggered or disconnected, preventing the system from running safely.
Your boiler has failed to ignite properly and stopped working because it did not detect a flame after several attempts.
Your boiler has temporarily stopped because it is not detecting enough water flowing through the system.
Your boiler is failing to ignite properly and has stopped working to keep you safe.
Your boiler's optional solar water heating sensor is disconnected or faulty, which may prevent your hot water from heating up correctly.
Your boiler's internal computer memory has encountered a reading or writing error, preventing the system from functioning correctly.
Your boiler's internal computer is struggling to talk to its control parts, preventing it from functioning correctly.
Your boiler’s main internal control board has developed a technical fault, preventing the system from starting up or operating safely.
Your boiler has been manually reset more than five times in fifteen minutes and has temporarily locked itself for safety.
Your boiler's internal computer is experiencing a communication error, meaning it has lost track of its own operational state and cannot safely run.
The internal computer that controls your boiler is experiencing a communication error and cannot operate the system safely.
Your boiler's internal computer is experiencing a communication error and has shut down to prevent potential hardware damage.
Your boiler has tried to start up, but it cannot detect a flame to keep it running safely.
Your boiler’s internal safety sensor thinks the burner is still lit even though it should be turned off, which prevents the system from starting safely.
Your boiler is struggling to keep the flame stable, which is preventing it from heating your water or home properly.
Your boiler tried to start up but couldn't create a flame on its first attempt, meaning you likely have no heating or hot water right now.
Your boiler has tried to start twice but has failed to successfully light its internal flame.
Your boiler has stopped during operation because the main burner flame has unexpectedly gone out.
Your boiler has shut down because the internal water temperature has become too hot, likely due to a blockage or a pump failure.
Your boiler has detected that the internal fan responsible for safely pushing exhaust gases outside is not spinning fast enough.
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BoilerFaultCodes