36 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler is currently in the middle of a specific installation mode while a heating valve part is being replaced.
Your boiler has detected a generic internal system error that prevents it from operating normally, and it requires a professional to diagnose the specific underlying cause.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler is trying to start but keeps failing to keep the flame lit, so it has shut down as a safety precaution.
Your boiler is failing to stay lit, which means it has safely shut itself down because it cannot consistently produce or hold a flame.
Your boiler has detected an issue with the fan that safely clears exhaust gases, preventing it from starting up for your safety.
Your boiler has detected a problem with the sensor that monitors the temperature of the water leaving the unit, meaning it cannot safely regulate heat.
Your boiler has detected a sensor problem that means it cannot accurately measure the temperature of the water returning to the unit, causing it to shut down for safety.
Your boiler is having trouble reading the outdoor temperature, which it uses to help run your heating more efficiently.
Your boiler has detected that the electrical supply coming into your home is too low for it to operate safely.
Your boiler has detected a software or data mismatch in its internal system settings, causing it to shut down for safety to prevent incorrect operation.
Your boiler has detected a communication error with its internal computer or a wiring fault near the gas supply, meaning it has safely switched off to prevent potential issues.
Your boiler has detected a software or configuration error in its internal computer, which has caused it to shut down for safety reasons.
Your boiler's main computer system has detected an internal configuration error, which usually happens immediately after a new part has been fitted without being set up correctly.
Your boiler's internal computer has suffered a critical failure and can no longer control the heating system, meaning the unit will not operate.
Your boiler's main control computer is experiencing a critical error and is unable to communicate properly, meaning your heating and hot water will not work.
Your boiler has detected that the temperature sensors for the water going in and out are reporting incorrect or swapped readings, which has caused the system to shut down for safety.
Your boiler has lost its flame while trying to run, which means it cannot heat your water or your radiators.
Your boiler has detected that heat is building up too quickly and cannot circulate around your home, likely due to a blockage or a pump failure.
Your boiler has detected a persistent internal fault and has automatically shut down for safety reasons.
Your boiler has switched itself off because the internal water temperature has become too hot, usually caused by a lack of water flow through the system.
Your boiler has failed to light several times and has shut down for safety, meaning you currently have no heating or hot water.
Your boiler has sensed a problem with the internal thermometer that monitors the water temperature leaving the unit, causing it to shut down for safety.
Your boiler's temperature-sensing component is malfunctioning, which prevents it from safely controlling the heat, so it has turned itself off to prevent overheating.
Your boiler has detected a sensor problem that means it cannot accurately measure the temperature of the water returning to the unit, causing it to shut down for safety.
Your boiler has detected an issue with the sensor that monitors the temperature of the water returning to the unit, causing it to stop running for safety.
Your boiler thinks a flame is burning even though it shouldn't be, causing the system to shut down for safety.
Your boiler's computer has detected an internal data error, meaning it has safely shut itself down until it can be reset or repaired by a professional.
Your boiler's internal computer has encountered a critical error and is unable to operate safely, meaning your heating and hot water will not function.
Your boiler has temporarily locked out because it failed to light or stay lit five times in a short space of time.
Your boiler has lost its flame while running, meaning it is not getting enough gas or the spark is failing to keep the burner lit.
Your boiler's electronic brain needs to be configured correctly by a qualified heating engineer after a recent replacement.
Your boiler is currently running a special software sequence used by engineers when replacing an internal water-directing valve.
This is an informational status code that appears on your boiler's screen after a heating engineer has finished repairing or replacing a valve part inside.
Your boiler is currently in a setup mode used by engineers to replace an internal valve part, and it requires professional completion.
Your boiler is displaying a setup code because it has detected a new control board being powered on for the first time.
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BoilerFaultCodes