45 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has failed to light because it cannot detect a flame, meaning you currently have no heating or hot water.
Your boiler is failing to light the flame properly after three attempts, which means it has safely shut down to prevent gas from building up.
Your boiler is unable to vent its waste gases properly because the exhaust pipe outside your home is blocked or restricted.
Your boiler has automatically turned itself off because it has detected that it is running much hotter than it should be.
Your boiler's computer has hit a minor, temporary hiccup and has paused itself to prevent any potential issues.
Your boiler has detected that your underfloor heating loop is getting too hot and has safely switched off to prevent damage.
Your boiler is failing to start because it cannot safely detect or ignite the internal flame.
Your boiler's internal computer is experiencing a memory error and can no longer safely control the system.
Your boiler's main control computer memory has become corrupted, meaning the system can no longer operate safely or reliably.
Your boiler's computer memory has become corrupted, preventing the internal software from starting up correctly.
Your boiler has lost the connection to a sensor that monitors the temperature of the water being sent to your radiators, which prevents it from heating your home safely.
Your boiler's internal computer is experiencing a critical error, meaning it cannot safely operate and requires a professional repair.
Your boiler’s internal computer has encountered a permanent software error and can no longer control the system safely.
Your boiler's computer is experiencing a temporary glitch that has caused it to stop working for safety.
The internal computer in your boiler has encountered an unrecoverable system error and is unable to operate safely anymore.
Your boiler is struggling to confirm that the flame has turned off properly after it finished its heating cycle, which is a safety mechanism to prevent gas buildup.
Your boiler has detected that a flame is still burning inside even though it has commanded the gas supply to turn off.
Your boiler has detected heat or fire inside before it has actually allowed any gas through, which is a significant safety protection feature that has now locked the system.
Your boiler's computer has experienced a temporary glitch or a permanent failure that is preventing it from operating correctly.
Your boiler's air circulation system is struggling to reach the speed required to fire up safely, so it has stopped working to prevent any potential issues.
Your boiler has stopped working because the mechanical part responsible for moving air through the system is failing to start, preventing the boiler from safely lighting.
Your boiler has stopped working because it is unable to accurately measure the temperature of the water inside it, likely due to a loose connection or a faulty sensor.
Your boiler has lost the signal from the sensor that monitors the temperature of the water returning to the unit, causing it to stop working for safety reasons.
Your boiler has detected that the water inside the system has become dangerously hot and has shut itself down as a safety precaution to prevent damage.
Your boiler is struggling to detect the temperature of the water in your hot water storage tank, meaning you likely have no hot water available at your taps.
Your boiler has lost its ability to accurately measure the water temperature because a sensor wire is faulty, so it has shut down as a precaution.
Your boiler has detected an electrical fault in a sensor that monitors the temperature of the water returning to the system, causing it to stop working for safety reasons.
Your boiler's internal computer is receiving conflicting or confusing signals regarding its operating temperature, causing it to shut down for safety.
Your boiler's internal computer is struggling to read its own temperature accurately, so it has shut down as a precaution to prevent overheating.
Your boiler is struggling to read its internal temperatures correctly, so it has shut down to prevent any damage to the system.
Your boiler is confused because it is getting conflicting or incorrect temperature signals, which stops it from working properly to keep your home warm.
Your boiler has lost the ability to read the temperature of your hot water tank, so it has stopped heating it to prevent overheating.
Your boiler's internal computer is experiencing a memory error and cannot start up, meaning your heating and hot water will not work until it is repaired.
Your boiler has detected a safety fault where it thinks a flame is present when it should be turned off, so it has shut itself down to keep your home safe.
Your boiler has detected that the electrical plug or wired connection has been installed with the power wires swapped around.
Your boiler has detected an issue with its electrical earthing system, which is a safety feature designed to prevent electric shocks.
Your boiler has detected that the exhaust gases are becoming too hot or that a sensor meant to monitor this temperature has developed a fault.
Your boiler has detected that the temperature in the flue is abnormally high or that a safety switch monitoring heat flow has tripped, causing the system to stop working to keep your home safe.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler's internal computer is failing to send signals to its parts, meaning the system cannot safely operate and is currently shut down.
Your boiler has blocked your attempts to restart it because the reset button was pressed too many times in a row.
Your boiler has detected an ongoing issue that was ignored or unresolved for over 24 hours, causing it to lock itself out as a safety precaution.
Your boiler has detected an electrical fault with one of its internal temperature sensors, which is preventing it from monitoring your heating system's water temperature correctly.
Your boiler has detected that your hot water is running much hotter than it should be, which suggests a valve is stuck and failing to mix in enough cold water.
Your boiler's additional temperature control unit has lost its electrical connection, which may stop your heating from running correctly.
BoilerFaultCodes