67 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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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 →
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Your boiler has detected that it is running too hot and has automatically slowed itself down to prevent any damage to its internal components.
Your boiler's electronic brain is unable to communicate correctly, which has caused it to lock out to prevent unsafe operation.
Your boiler's main control computer is experiencing an error, which has caused it to stop the burner from operating to prevent further issues.
Your boiler's electronic brain is malfunctioning and needs to be replaced by a professional to get your heating system running again.
Your boiler's electronic control brain is experiencing a internal fault and is unable to safely ignite the burner.
Your boiler's temperature sensor is disconnected or faulty, meaning it cannot accurately track the heat of the water and has stopped your heating from working.
Your boiler's temperature sensor is failing to communicate properly, which is preventing it from heating your water correctly.
Your boiler's internal control brain is experiencing an electronics failure and can no longer reliably signal the system to move hot water around your home.
Your boiler's central control board is struggling to signal the water pump, which means your heating may not turn on or circulate effectively.
Your boiler is struggling to detect the temperature of your hot water supply, which means it will likely stop heating your water until a faulty sensor or internal control board is replaced.
Your boiler is having trouble sensing the temperature of your hot water supply, which means it cannot heat your water properly.
Your boiler is struggling to accurately measure the temperature of the water inside its internal storage tank, which means it may fail to provide hot water correctly.
Your boiler is having trouble communicating with one of its internal temperature sensors, which means it has stopped providing hot water as a safety precaution.
Your boiler's electronic brain is experiencing a minor internal error and needs a service visit to replace a faulty control component.
Your boiler's control computer is failing to communicate correctly with the water heating pump, which means the system cannot reliably produce hot water.
Your boiler has failed to light the burner and is currently locked out to prevent any issues.
Your boiler has stopped heating because the internal water pump, which moves hot water around your house, has seized up or failed and cannot restart itself.
Your boiler is struggling because the internal water pump is stuck or not receiving power, which prevents heat from circulating through your home.
Your boiler is struggling to light itself correctly because the internal firing mechanism is becoming partially blocked or worn out.
Your boiler is currently undergoing a safety timing delay, which typically occurs after it has failed to ignite successfully on the first attempt.
Your boiler is currently preparing itself to ignite by clearing out the combustion chamber, which is a normal part of the startup cycle.
Your boiler has detected an internal light source that shouldn't be there, so it has safely shut itself down to prevent ignition.
Your boiler has detected light inside the combustion chamber when it should be dark, causing it to lock itself out as a safety precaution.
Your boiler has stopped working because the amount of water in your heating system is too low to run safely.
Your boiler is currently just waking up and going through a brief safety check before it ignites the flame to start heating your home.
Your boiler is failing to start because it detects light inside the combustion chamber when it should be completely dark, preventing it from igniting safely.
Your boiler has detected a signal that it is already burning fuel even though it has not been told to start, so it has safely shut itself down to prevent an unsafe situation.
Your boiler has stopped working because it failed to light the burner, meaning you currently have no heating or hot water.
Your boiler has failed to start after several repeated attempts and has now automatically shut down for safety to prevent fuel buildup.
Your boiler has disabled itself for safety after multiple failed attempts to start the burner, and it now requires a specific cooling period or a professional reset to clear the lock.
Your boiler has detected an internal electrical issue affecting the fuel delivery system, which is preventing it from firing up safely.
Your boiler is unable to safely vent exhaust gases because the air-moving fan inside the unit has failed or lost its electrical connection.
Your boiler's electronic brain is experiencing a communication error, which is preventing it from firing up reliably.
Your boiler is struggling to push out fumes correctly when it tries to start, which can lead to dangerous exhaust gases leaking into the air supply.
Your boiler is detecting that exhaust fumes are not properly contained, which means there is a potential risk of dangerous gases escaping into your home environment.
Your boiler is displaying a recognition code because it is identifying its internal configuration settings, rather than indicating a system malfunction.
Your boiler is displaying its specific model identification code, which is an internal manufacturer setting rather than a functional fault or error.
Your boiler is displaying an internal identification code rather than an active fault, indicating the system's computer may need to be reset or reconfigured by a professional.
Your boiler is failing to ignite because it is not receiving any oil to burn.
Your boiler is currently switched off or not receiving any power, preventing it from heating your water or home.
Your boiler has failed to ignite even though it has power and fuel, so it has safely shut itself down to prevent any issues.
Your boiler is struggling to keep its flame lit after it starts up, causing it to shut down for safety reasons.
Your boiler is not burning fuel correctly and is producing smoke, which indicates a serious safety issue that requires professional attention immediately.
Your boiler is struggling to breathe properly, causing the flame to struggle and the unit to make a repetitive pulsing or thumping sound.
Your boiler is struggling to keep its flame lit properly when it first tries to start up.
Your boiler is failing to get hot enough because it is not receiving the correct amount of fuel or is set up incorrectly, meaning it cannot provide you with heating or hot water.
Your boiler has detected that it is becoming dangerously hot and has shut itself down to prevent damage, likely because water is not flowing through the system properly.
Your boiler is struggling to clear exhaust gases effectively when it tries to start, which can lead to smoke or fumes leaking out.
Your boiler is leaking heating oil, which creates a strong smell and poses a potential fire and environmental hazard.
Your boiler is allowing burnt gases to escape inside or near the unit, which is a serious safety concern that requires an immediate professional inspection.
Your boiler has detected a temporary issue with the burner and has safely shut itself down to prevent any damage.
Your boiler has detected that the water inside it is getting too hot and has automatically paused to prevent overheating, but it should restart once it has cooled down sufficiently.
Your boiler is working exactly as it should and there are no issues detected.
Your boiler has completely lost power and is unable to turn on, meaning it cannot provide any heating or hot water.
Your boiler has detected a problem with the burner ignition and has safely shut itself down to prevent any issues.
Your boiler has stopped itself from running as a safety precaution because the fuel failed to ignite properly.
Your boiler has stopped working to protect itself and needs a manual reset to try and start up again.
Your boiler has detected an issue preventing it from lighting and has shut down for safety; it needs a manual reset to try and start again.
The water pressure inside your heating system has dropped too low, so the boiler has turned itself off to prevent any damage.
Your boiler has lost all power and is completely shut down, meaning it cannot provide any heating or hot water until the electrical supply is restored.
Your boiler’s electrical supply is unstable, meaning the electricity coming from your home is not consistent enough for the boiler to operate safely.
Your boiler is struggling to receive a stable electrical supply, which is likely being caused by fluctuations in the power coming from your home's mains.
Your boiler has automatically turned itself off because it has become too hot, which is a safety feature to prevent damage or dangerous conditions.
Your boiler has switched itself off because it has become dangerously hot, likely due to a circulation problem or a system blockage.
Your boiler has detected that it is getting too hot and has automatically shut down to prevent any damage or safety issues.
Your boiler has stopped working because it failed to ignite or stay lit, requiring an internal safety reset.
Your boiler has stopped working because it failed to light the fuel inside, likely due to a blockage in the oil supply or a dirty sensing component.
BoilerFaultCodes