33 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Flexicom sx
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Your boiler has detected a problem with the sensor that monitors hot water temperature, likely due to a loose connection or a fault in the internal wiring.
Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit.
Your boiler has failed to ignite and has shut itself down for safety, meaning you will not have any heating or hot water until it is reset or repaired.
Your boiler has stopped working because a sensor that monitors the temperature of the water returning from your radiators has developed a fault.
Your boiler has switched itself off for safety because it has reached an excessively high temperature, likely due to a circulation problem.
Your boiler has detected a problem with the sensor that measures the temperature of the water leaving the unit, causing it to shut down as a safety precaution.
Your boiler has detected an issue with the sensor that monitors the temperature of the water coming back from your radiators, preventing it from heating your home safely.
Your boiler has lost communication with the sensor that monitors the temperature of your hot water cylinder, meaning it cannot heat your water correctly.
Your boiler's hot water sensor has developed a technical fault, preventing the system from accurately measuring and heating your water.
Your boiler has switched itself off to prevent damage because the internal water temperature has become too hot.
Your boiler has detected that the water pressure is too low to operate safely and has shut down to prevent damage.
Your boiler has stopped working because the water isn't moving through the system fast enough, causing the internal temperature to rise too quickly.
Your boiler is heating up too quickly because water isn't flowing through the system properly, causing it to shut down to prevent overheating.
Your boiler has switched itself off because the internal exhaust gases have reached a temperature that is too high, often caused by a circulation problem or a lack of water.
Your boiler has detected a problem with how gas is flowing into the system, which means it cannot light safely and has shut down as a precaution.
Your boiler has sensed a flame when there shouldn't be one, or the sensor that monitors the fire is sending a confusing signal to the control board.
Your boiler is failing to light the gas flame, which means your heating and hot water will not work until the system is reset or repaired.
Your boiler has lit successfully but then lost its flame while it was running, causing the system to shut down for safety.
Your boiler has lost its memory of whether it is a 24kW or 30kW model, meaning it cannot operate safely until its settings are re-programmed.
Your boiler has lost communication with its external controls like your thermostat because there is an electrical problem with the wiring connecting them.
Your boiler has detected an internal communication failure between the main control board and the gas valve, meaning it cannot safely light the flame.
Your boiler has detected an internal electronics failure that prevents it from safely controlling the gas supply, meaning it has shut down for safety.
Your boiler's internal computer brain has developed a memory error and can no longer process its instructions correctly.
Your boiler’s internal computer brains are struggling to talk to each other, meaning the system cannot run safely.
Your boiler's internal computer boards are having trouble communicating with each other, preventing the system from starting up.
Your boiler's internal computer boards have stopped communicating correctly, meaning the system cannot process commands or operate safely.
Your boiler's main control board has lost communication with its internal identity chip, effectively meaning the boiler has forgotten which model it is and cannot operate.
Your boiler is struggling to accurately measure the water temperature, causing it to shut down to prevent overheating.
Your boiler is struggling to read its own water level because of an electrical sensor issue, which has caused it to stop working as a safety precaution.
Your boiler is having trouble measuring how much water is inside the system, which is causing it to stop running for safety.
Your boiler has stopped working because it cannot detect the necessary change in water pressure required to safely start the heating process.
Your boiler has detected an issue with the system that removes waste water or measured a temperature imbalance, causing it to shut down as a safety precaution.
Your boiler is struggling to heat up water for your taps because the internal pump or sensor that manages hot water is not working correctly.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes