20 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Baxi Combi 105 HE
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 detected a general internal fault that prevents it from starting, meaning you currently have no heating or hot water.
Your boiler is failing to light the internal flame, which could be due to a blockage in the waste water pipe or an issue with the gas ignition system.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage or dangerous overheating.
Your boiler is struggling to circulate water, likely because there is not enough pressure in the system or the internal pump has stopped working.
Your boiler is struggling to circulate water, likely because there is not enough water inside the system or the internal pump has stopped working.
Your boiler has lost the ability to accurately measure the temperature of the water circulating through your radiators, so it has shut down to prevent overheating.
Your boiler has stopped working because it is unable to accurately measure the temperature of the water used for your radiators.
Your boiler has no electricity flowing into it, meaning it is completely turned off and cannot heat your home or provide hot water.
Your boiler is failing to start because it is not receiving the electrical signal required to activate the water pump.
Your boiler is struggling to circulate water properly, likely due to low pressure or a sticking internal component that prevents hot water from reaching your radiators or taps.
Your boiler has stopped working because it cannot detect the water flow needed to safely ignite or move heat around your home.
Your boiler is failing to clear its combustion gases safely, so it has shut down to prevent any risk of fumes entering your home.
Your boiler is failing to ignite because it cannot receive the gas supply it needs to produce a flame.
Your boiler is struggling to control its gas flame correctly, which prevents it from safely heating your home or water.
Your boiler is failing to light the burner, meaning it cannot produce heat or hot water.
Your boiler is failing to detect that it has successfully lit the flame, so it is turning itself off as a safety precaution.
Your boiler has detected that it is getting too hot and has automatically switched itself off to prevent any damage or safety issues.
Your boiler's control panel is struggling to recognise the settings you have selected, preventing it from starting up properly.
Your boiler's waste water pipe is blocked, preventing it from safely draining away the moisture it collects during operation.
Your boiler has detected that the flue exhaust is becoming dangerously hot and has shut itself down to prevent damage or fire risk.
BoilerFaultCodes