28 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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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 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 is unable to read the temperature of your hot water cylinder because the connection to the sensor has been lost or damaged.
Your boiler has lost communication with the solar heating control panel, meaning your solar panels won't be helping to heat your water.
Your boiler is struggling to accurately gauge the weather outside, meaning it might not provide the right amount of heat for your home.
Your boiler has lost its connection to the outside temperature sensor, meaning it cannot automatically adjust your heating based on the weather.
Your boiler has detected an electrical fault with a sensor that monitors the water temperature flowing into your heating system, leading it to shut down for safety.
Your boiler has lost connection with a temperature sensor that monitors the main water flow, likely due to a broken wire or a faulty sensor.
Your boiler has stopped heating because a internal sensor that monitors water temperature has developed an electrical fault and is preventing the burner from firing.
Your boiler has failed to ignite or stay lit, meaning your heating and hot water have stopped working.
Your boiler has stopped working because it can no longer accurately measure the temperature of the water inside the system.
Your boiler has stopped working because it thinks the hot water tank is dangerously overheating due to a faulty electrical sensor.
Your boiler has stopped providing hot water because the internal sensor that measures water temperature has detected a technical fault or a short circuit.
Your boiler has stopped working because a sensor that monitors the water temperature has developed an electrical fault.
Your boiler has stopped providing hot water because the internal sensor that measures water temperature is broken or disconnected.
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 is having trouble communicating with the wall-mounted thermostat control because of a setup or configuration error.
Your boiler is having trouble communicating with its internal pump, which means it cannot properly move heated water around your system.
Your boiler is having trouble communicating with the internal pump that moves hot water around your heating system.
Your boiler is having trouble communicating with an add-on control or an external smart home accessory, which may affect its ability to run efficiently.
Your boiler has stopped working because there is not enough water flowing through the system to keep it running safely.
Your boiler has failed to light the flame, which means it cannot provide any heating or hot water until the issue is resolved.
Your boiler has stopped working because it cannot correctly detect the water pressure, causing the system to shut down for safety.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes