97 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler's internal computer system is having trouble talking to its main control unit, meaning the appliance cannot tell itself to heat your home or water.
Your boiler has lost the ability to 'talk' to its display, meaning it cannot receive commands or show you what it is doing.
This is a settings status rather than a fault, indicating the maximum amount of heat the boiler is currently allowed to produce for your radiators.
Your boiler is simply running the internal pump for a few minutes after the heating has switched off to cool down the internal components safely.
Your boiler is taking a planned temporary break to prevent the system from turning on and off too frequently, which helps save energy and protect internal parts.
Your boiler is currently in a brief, automatic resting period between heating cycles to prevent excessive wear on the system.
Your boiler is displaying the current temperature of the water inside your hot water storage cylinder.
Your boiler is simply displaying the target temperature it is currently trying to reach for your radiators; this is an information status code rather than a fault.
Your boiler is displaying the temperature setting you have chosen for your hot water tank rather than indicating a system fault.
This is a status code rather than a fault, showing whether your external room thermostat is currently telling the boiler to turn the heating on or off.
Your boiler is simply displaying the target temperature being requested by your external room thermostat, which is a normal status message rather than an actual fault.
Your boiler is simply showing that the internal pump is currently running to move water through your heating system.
Your boiler is providing an update on the operation of the external pump that helps circulate water through your heating system, though this is often an information code rather than a breakthrough failure.
Your boiler is displaying the current operating status of the external pump that moves hot water around your system, rather than indicating a breakdown.
Your boiler is currently set to a configuration mode that requires an adjustment to how water is circulated through your heating system.
This is a normal status message showing whether your room thermostat is currently telling the boiler to turn the heating on or off, rather than a system fault.
Your boiler has been manually adjusted to manage its heat using the return pipe temperature rather than the flow pipe temperature, which is a setting change rather than a breakdown.
Your boiler is currently performing a standard cool-down process after providing heating or hot water, and this code is an information status rather than a fault.
Your boiler is currently set to the maximum allowed temperature for your hot water storage, which is an advisory status rather than a breakdown.
This is a normal status indicator showing that your boiler is currently receiving a signal to provide heating.
Your boiler's internal water pressure sensor is checking if there is enough water flow to operate safely.
Your boiler is currently busy heating your hot water cylinder or keeping its internal water warm so you get hot water quickly.
Your boiler is having trouble communicating with an internal switching component that manages external parts like pumps or valves.
Your boiler is confused about how it should be sending power to an external component, such as a pump or a zone valve, due to a settings mismatch.
Your boiler is currently set to a specific mode for how it refills with water, and this code is simply an information setting rather than a breakdown.
Your boiler is struggling to correctly control the speed of its fan, which is preventing the system from clearing waste gases and beginning the ignition process.
Your boiler is currently showing you a diagnostic information screen regarding how fast the fan is spinning, rather than an actual fault code.
Your boiler is displaying its current heating water temperature and this is a normal status reading rather than a breakdown code.
Your boiler is displaying the current temperature of the water returning from your radiators to the unit.
Your boiler is confused about how hot it needs to make the radiators because a background setting used for outdoor temperature sensors is missing or incorrect.
This is an informational setting showing the lowest temperature your heating system will drop to, rather than an actual fault with the boiler.
Your boiler is struggling to read the outdoor temperature, which may affect how efficiently it balances your heating, but it should still provide warmth.
Your boiler's computer is making small internal adjustments to how the fan runs to ensure it stays efficient and safe.
Your boiler is notifying you that it is automatically adjusting its fan speed to maintain correct airflow, but this may indicate an underlying component issue.
Your boiler is notifying you that it is currently using extra heat to warm up your solar water heating system.
Your boiler is temporarily pausing because internal temperature sensors have detected heat rising too quickly, likely due to a circulation issue.
This is a diagnostic information code showing the total count of times your boiler has successfully started up, rather than an active fault with the system.
Your boiler is simply indicating that it has dropped to a lower target temperature for the night to save energy.
Your boiler is taking longer than expected to light the flame, which is currently an advisory warning rather than a total breakdown.
Your boiler is struggling to light the flame correctly or is taking too long to start up, which has caused it to stop running for safety.
Your boiler is notifying you that it has pre-heated the internal components so that your hot water arrives at your taps more quickly.
Your boiler is taking a temporary scheduled break to prevent the burner from switching on and off too frequently, which helps save energy and protect internal parts.
Your boiler is struggling to light its flame on the first try, which may eventually lead to it failing to provide heating or hot water if it isn't fixed.
Your boiler is struggling to light itself correctly and has failed multiple attempts to start up.
Your boiler is notifying you that the maximum temperature limit for your heating water has been reached or set.
Your boiler has timed out because it is taking much longer than expected to heat your hot water cylinder.
Your boiler is struggling to bring your hot water cylinder up to the required temperature within the expected time limit.
Your boiler's memory of past errors has been successfully cleared and it is now operating normally.
Your boiler is currently reverting its internal settings back to the manufacturer's original state.
Your boiler has lost its connection to the sensor that measures how hot the water is inside it, preventing it from heating your home safely.
Your boiler has lost its connection to the sensor that monitors the water temperature returning to the unit, causing it to shut down for safety reasons.
Your boiler has stopped working because a sensor that monitors water temperature has developed a faulty faulty connection or failed completely, causing the system to shut down for safety.
Your boiler has stopped working because a sensor that measures the temperature of water returning to the system is providing an incorrect signal, causing a safety shutdown.
Your boiler is struggling to read the temperature of your hot water cylinder because a sensor or its connecting wire has developed a fault.
Your boiler is having trouble detecting the temperature of your hot water, which means it may struggle to provide a consistent hot shower or turn off the tap water heating properly.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler has detected that the water is heating up significantly faster than it can move around the system, so it has safely turned itself off to prevent overheating.
Your boiler has detected that the water inside is heating up far too quickly for the system to handle, so it has shut down to prevent damage.
Your boiler has detected that the exhaust gases are becoming dangerously hot and has shut itself down to prevent overheating or fire risk.
Your boiler has detected an internal error where it mistakenly believes a flame is present when the burner is actually turned off, preventing it from starting safely.
Your boiler is trying to start up but cannot successfully light the flame needed to heat your water.
Your boiler has stopped because the flame inside has gone out and will not stay lit.
Your boiler has detected an issue with the internal ventilation system that helps move exhaust gases safely out of your home, so it has shut down to prevent unsafe operation.
Your boiler's internal communication system is failing to send signals correctly, which is preventing it from firing up.
Your boiler has detected an internal communication error with the gas control system, meaning it will not light because it cannot safely manage your fuel supply.
Your boiler has detected that the internal gas valve is not closing correctly when it should, which prevents the unit from starting safely.
Your boiler's computer memory has encountered an internal error, which prevents it from operating correctly and requires a specialist to reset or replace the main circuit board.
Your boiler's computer is struggling to read internal sensor signals, causing it to shut down to prevent incorrect operation.
Your boiler’s control brain is overheating, which has triggered a safety shutdown to protect the internal electronics from damage.
Your boiler has detected an internal communication error with its flame monitoring system and has shut down for your safety.
Your boiler is struggling to keep the flame lit reliably, causing it to shut down for safety reasons.
Your boiler's computer has lost its internal identification settings, essentially forgetting which specific model it is, which prevents it from operating correctly.
Your boiler is struggling to accurately measure the temperature of the water flowing into your heating system, so it has stopped working to prevent potential damage.
Your boiler has detected an inconsistent temperature reading between its internal pipes, meaning it cannot accurately measure how well it is heating your water.
Your boiler has detected that the internal sensor responsible for monitoring water pressure is sending an incorrect electrical signal, meaning the system may not be able to accurately tell how much water is inside.
Your boiler's internal water pressure gauge is sending a confused signal to the control panel, meaning the system cannot accurately read how much pressure is in the pipes.
Your boiler is not detecting the necessary water movement to safely ignite and provide heating or hot water, usually because the internal system pressure is too low or a sensor is blocked.
Your boiler has detected that it is getting too hot inside and has safely turned itself off to prevent damage.
Your boiler has detected a problem with the system that safely removes waste water or controls exhaust gases, causing it to shut down to prevent damage.
Your boiler has lost the connection to the temperature sensor that controls your hot water, meaning it cannot properly heat the water for your taps.
Your boiler is struggling to detect the expected temperature difference between the water leaving and returning to the system, causing it to shut down to prevent damage.
Your boiler is confused because the temperature readings between different parts of the system don't match, causing it to shut down to prevent damage.
Your boiler's internal temperature probe has been identified as being loose or incorrectly positioned, meaning it cannot accurately read the water temperature to heat your home safety.
Your boiler has lost the signal from the contact sensor that monitors your underfloor heating system, preventing it from heating that specific area.
Your boiler is failing to light the flame properly, meaning it cannot produce heat or hot water.
Your boiler is struggling to control its internal gas flow, which has triggered a safety shutdown to prevent the unit from operating incorrectly.
Your boiler's water circulation system is failing, which means the device cannot move heat around your home effectively.
Your boiler has lost the ability to read the temperature of your hot water cylinder, which means it cannot safely heat your tap water.
Your boiler has encountered a general communication or system error that it cannot identify with a specific sub-code, causing it to stop running for safety.
Your boiler is currently running a self-cleaning air removal cycle to clear trapped air from the system pipes.
Your boiler is currently running a professional diagnostic test to check its performance at full power, rather than showing a breakdown fault.
Your boiler is currently performing a routine automated safety check after starting up to ensure it is running efficiently.
Your boiler is confused because it is looking for a smart controller that isn't connected, causing it to stop its automatic setup process.
Your boiler is currently in a manual filling or draining mode, which is why it is temporarily preventing the heating and hot water from working.
Your boiler is operating normally and is currently running to provide heating to your radiators.
Your boiler is currently working exactly as it should, warming up the water for your taps and shower.
BoilerFaultCodes