25 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Logic Combi
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 minor electronic sensor issue and is running at a lower power level to keep your home warm until it can be serviced.
Your boiler has detected a problem with the sensor that monitors the temperature of your central heating water, meaning it can't heat your radiators safely.
Your boiler has detected a problem with how it moves air and exhaust gases through the system, preventing it from firing up safely.
Your boiler has detected a sensor problem that is preventing it from providing hot water correctly.
Your boiler has tried to start up but failed to ignite the gas flame, causing the system to shut down for safety.
Your boiler has stopped working because a sensor that measures water temperature is providing an incorrect reading or has become disconnected.
There is a minor leak from a seal within the boiler's internal plumbing which needs to be tightened or replaced to stop water dripping inside the unit.
Your boiler has stopped working because an internal electrical safety fuse has blown, cutting off power to the system's control board.
There is a small physical seal inside your boiler that has likely failed, causing a internal water drip.
Your boiler has tried to start up but cannot light the gas flame, which means your heating and hot water will not work.
Your boiler has detected that there is not enough water in the system to operate safely, causing it to shut down temporarily.
Your boiler has detected an issue with the seal around the observation window, which could lead to unsafe gases escaping into your home.
Your boiler is struggling to detect the flow of water because the internal sensor or its protective filter is likely clogged or faulty.
Your boiler is struggling to switch between heating your radiators and heating your hot water taps, which may cause one or both to stop working correctly.
Your boiler is struggling to detect the flame needed to heat your water, so it has safely shut itself down to prevent any issues.
Your boiler is failing to light the flame properly because it cannot accurately detect or send the spark needed to start the fire.
Your boiler is failing to detect a flame when it tries to light, so it has safely shut down to prevent gas buildup.
Your boiler is struggling to confirm it is venting exhaust gases safely, so it has stopped working to prevent any risk.
Your boiler has detected that water is not circulating properly through your heating system, so it has safely shut down to prevent damage.
Your boiler has detected trapped air inside the system, which is preventing water from circulating correctly to provide you with heating and hot water.
Your boiler has detected that one of its outer side casing panels is not fitted correctly or is loose, which prevents the boiler from operating safely.
Your boiler has detected that the seals around the combustion area are not airtight, which prevents the unit from operating safely.
Your boiler has detected that the exhaust gases are getting too hot, so it has turned itself off to prevent overheating.
Your boiler is trying to start up but cannot light the gas to create a flame, meaning you will have no heating or hot water.
Your boiler has detected that it got too hot and has automatically shut itself down to prevent internal damage.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes