35 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has detected an issue with the gas pressure or a component failure and has shut down as a safety precaution.
Your boiler has shut down because the electrical power coming into it is too weak or unstable to run safely.
Your boiler has shut down because it is struggling to discharge exhaust fumes safely or is detecting a significant lack of air flow.
Your boiler has shut itself down as a safety precaution because it has detected an overheating issue within the system.
Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Your boiler has detected a sequence error or a flame signal where there shouldn't be one, causing the burner to shut down completely for safety.
Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Your boiler has detected a sequence error or a flame signal where there shouldn't be one, causing the burner to shut down completely for safety.
Your boiler is receiving an incorrect reading from the sensor that monitors the air temperature outside, which may cause your heating system to run less efficiently.
Your boiler is currently unable to read the temperature outside, which may cause it to run slightly less efficiently than usual.
Your boiler's temperature sensor is reporting an electrical fault, meaning the system cannot accurately measure how hot the water is, so it has shut down as a safety precaution.
Your boiler has failed to ignite or stay lit, meaning your heating and hot water have stopped working.
Your boiler has lost the signal from the sensor that monitors your heating water temperature, so it has shut down to prevent overheating.
Your boiler is struggling to accurately measure the temperature of the water in your hot water tank, which may cause it to stop producing hot water to protect the system.
Your boiler has stopped working because it is unable to accurately read the temperature of the water inside the system due to a faulty electrical connection or sensor.
Your boiler has lost the connection to the sensor that measures the temperature of your hot water tank, meaning it cannot accurately heat your water.
Your boiler has lost the connection to the sensor that measures how hot your water is, meaning it cannot safely regulate the temperature.
Your boiler has sensed that the internal pump is malfunctioning or water is not circulating correctly, which has caused the system to stop as a safety precaution.
Your boiler has detected that the water pump is likely stuck or not moving water correctly, which means the system cannot heat up safely.
Your boiler is having trouble 'talking' to your thermostat, which means it might not know when to turn your heating on or off.
Your boiler has detected an electrical fault in the sensor that monitors the temperature of the gases leaving your flue, meaning the boiler has safely shut down to prevent potential damage.
Your boiler has detected a disconnected wire or a faulty sensor monitoring the temperature of the exhaust gases, causing it to shut down for safety reasons.
Your boiler has detected a safety interruption in its internal systems and has shut down to prevent any risk of overheating or unsafe operation.
Your boiler has detected an internal electronic error that is preventing it from starting safely.
Your boiler has detected an internal electronic error that is preventing it from starting up correctly.
Your boiler has detected that the exhaust gases are becoming dangerously hot and has shut itself down to prevent damage or fire risk.
Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.
Your boiler has detected that a flame is present before it has actually been told to start, which prevents it from safely igniting.
Your boiler is failing to light because it cannot detect a flame, meaning you currently have no heating or hot water.
Your boiler has identified a problem with the ventilation system and has shut down as a safety precaution because it cannot confirm that exhaust fumes are being cleared correctly.
Your boiler has detected that a gas valve inside the unit is not shutting off as quickly as it should, which triggers a safety shutdown to prevent any risk.
Your boiler is failing to ignite because the internal air fan is not spinning fast enough to clear the system for safe startup.
Your boiler has detected an internal communication error with the internal fan, which means it will stop working to ensure your safety.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes