26 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Main Eco Compact
This boiler uses indicator light combinations
Note which lights are on, off, or flashing and at what speed. Match the combination to the cards below. Do not reset until you have noted the pattern. How to read fault codes →
Tap any card for details
Your boiler is displaying warning lights to signal an internal fault that is preventing it from operating correctly.
Your boiler has detected that it is running too hot and has automatically turned itself off to stay safe.
Your boiler is trying to start but cannot light the internal flame, which means it has stopped providing heating and hot water for safety reasons.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.
Your boiler is struggling to clear exhaust gases safely, so it has stopped working to prevent any risk of fumes entering your home.
Your boiler has stopped working because it has lost the ability to accurately measure the temperature of the water circulating through your radiators.
Your boiler is struggling to accurately detect the temperature of your hot water, which means it will likely stop producing hot water until the faulty sensor is replaced.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.
Your boiler has lost the ability to accurately measure the temperature of the water circulating through your radiators, so it has shut down to protect the system.
Your boiler has detected that the water inside it has become too hot because it cannot circulate properly, so it has automatically shut down to prevent damage.
Your boiler has detected a communication issue with the sensor that monitors the temperature of the gases leaving your flue, causing it to stop working to ensure your safety.
Your boiler has detected a flame inside when it is switched off, so it has safely shut itself down to prevent a fire or gas hazard.
Your boiler is struggling to accurately measure the temperature of the water used for your taps, causing it to stop heating your hot water.
Your boiler has detected that it is getting too hot and has automatically switched itself off to prevent damage.
Your boiler has stopped working because the water pressure inside the system is too low to operate safely.
Your boiler has detected that water is not circulating correctly through the system, which is preventing it from heating your home or water safely.
Your boiler has detected that the gases being sent out through your chimney are getting too hot and has automatically shut down to keep your home safe.
Your boiler is failing to light because it cannot detect a flame or is not receiving a consistent supply of gas.
Your boiler has detected that the internal fan responsible for safely venting exhaust gases is not working correctly, causing the system to stop for safety reasons.
Your boiler is failing to circulate water correctly before firing up, which prevents it from safely producing heat or hot water.
Your boiler has stopped working because it failed to light or lost its flame during operation, so it has turned itself off for safety.
Your boiler has stopped working because it couldn't light the flame, so it has safely shut itself down.
Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.
Your boiler has lost the water pressure it needs to circulate heat, so it has safely shut itself down to prevent damage.
Your boiler has failed to start up or keep its flame lit and has safely switched itself off to prevent gas build-up.
Your boiler has switched itself off because it has become too hot inside, preventing potential damage.
BoilerFaultCodes