21 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler is failing to ignite because it is not receiving the necessary electrical signal to open the gas supply.
Your boiler has stopped working because an internal electrical safety fuse has blown, meaning the system is currently unable to power its internal components.
Your boiler has stopped working because an internal safety fuse has blown, preventing the electronic control system from powering up.
Your boiler's air extraction system is struggling to maintain a steady speed, which prevents the unit from starting or running reliably.
Your boiler has no electricity flowing to it, meaning it cannot start up to provide heating or hot water.
Your boiler is failing to detect an electrical power supply, meaning it cannot switch on or operate your heating and hot water.
Your boiler is failing to detect a proper power connection, which prevents it from firing up safely.
Your boiler is not receiving any power, meaning it is completely turned off and cannot provide heating or hot water.
Your boiler has stopped working because a safety sensor has triggered a shutdown to prevent it from getting too hot.
Your boiler has stopped heating because it has detected a heat safety issue and automatically shut down to prevent damage.
Your boiler has shut down because it thinks it is overheating, meaning you currently do not have heating or hot water.
Your boiler has automatically shut itself down because it detected that it is getting too hot, likely due to a flow restriction or a failing safety sensor.
Your boiler has detected an issue with its internal air supply system, which is preventing it from igniting or staying lit.
Your boiler is failing to confirm that the flue system is clear, which is preventing it from igniting for your safety.
Your boiler has stopped working because it cannot confirm that air is flowing correctly through the system to burn fuel safely.
Your boiler is failing to clear combustion gases properly, so it has safely shut itself down to prevent any risk.
Your boiler has stopped working because the main control panel is failing to send electrical power to the internal gas valve to start the heating process.
Your boiler has stopped working because the internal control board is failing to send electrical power to the gas valve.
Your boiler has detected an internal electrical communication error on its main control system that prevents it from starting safely.
Your boiler is failing to light the burner, meaning it cannot produce heat or hot water because it has detected an issue with the ignition process.
Your boiler is failing to ignite because the small flame that acts as a match to start the main burner will not stay lit.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes