30 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Flexicom cx
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Your boiler has stopped working because it cannot accurately measure the temperature of the water leaving the unit.
Your boiler has stopped working because a sensor that measures the temperature of the water returning to the unit has developed a fault or disconnected.
Your boiler has stopped working because it cannot light the gas to start the heating process.
Your boiler has stopped working because a sensor that monitors the temperature of the water leaving the unit has failed or disconnected.
Your boiler has stopped working because a sensor that monitors the temperature of the water returning to the unit has developed an electrical fault.
Your boiler has lost communication with the temperature sensor on your hot water cylinder, meaning it cannot tell how hot your water is.
Your boiler has reached an unsafe temperature and has automatically shut down to prevent damage or safety issues.
Your boiler has detected that there is not enough water pressure in the system to operate safely, which has caused it to shut down.
Your boiler has sensed that water is not circulating through the system properly, causing a large temperature gap between the pipes leaving and returning to the unit.
Your boiler is overheating because water isn't moving through the system fast enough, causing it to shut down to prevent damage.
Your boiler has switched itself off because the waste gases are getting too hot, which is usually caused by a lack of water circulating through the system.
Your boiler has stopped working because an internal motor that controls the gas flow is not moving as it should.
Your boiler has stopped working because it cannot confirm that the flame is staying lit safely.
Your boiler has failed to ignite and is not receiving a steady gas supply or spark, meaning you currently have no heating or hot water.
Your boiler was running but the flame has unexpectedly gone out, causing the system to stop working as a safety precaution.
Your boiler has detected an issue with the fan that safely clears exhaust gases, causing the system to shut down for safety.
Your boiler has detected an issue with one of its internal sensors, preventing it from safely controlling your heating and hot water.
Your boiler's main control unit is confused because a specific internal configuration component is missing or has the wrong electrical profile.
Your boiler's main control board has suffered a communication failure or internal electrical fault, meaning it can no longer send instructions to heat your home.
Your boiler's main control board has suffered an internal electronic failure and is unable to manage the heating process safely.
Your boiler's main internal computer has developed a communication failure, meaning it can no longer control the heating and hot water functions.
Your boiler's main internal computer has developed a communication or hardware error and cannot manage the heating process safely.
Your boiler’s internal computer has developed an electronic fault, preventing the system from running safely.
Your boiler's internal computer has encountered a critical communication error and can no longer control the heating system safely.
Your boiler's internal control boards are not communicating correctly because they do not recognise each other's software or settings.
Your boiler has detected that its temperature sensors are giving conflicting readings or have failed, which has caused the system to stop working for safety.
Your boiler has stopped working because it cannot accurately measure the water pressure due to a sensor or wiring issue.
Your boiler has lost the ability to monitor its own water pressure, meaning it has shut down as a safety precaution.
Your boiler is struggling to detect a rise in water pressure when the pump starts, which is preventing it from firing up to provide heating or hot water.
Your boiler has stopped working because the system that removes waste water is blocked or the pump used to drain it has failed.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes