63 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler is currently running normally but has detected a minor issue that requires attention before it potentially stops working altogether.
Your boiler has lost the connection to the external sensor that tells it how cold it is outside, so it is currently operating in a default mode.
Your boiler has stopped working because it cannot detect the water pressure in the system, usually due to a loose wire or a faulty sensor connection.
Your boiler has detected that the fuel and air mixture used to heat your home is not burning correctly, so it has safely shut itself down to prevent unsafe operation.
Your boiler has detected that the water pressure inside your heating system has dropped too low, which prevents it from working correctly.
Your boiler has lost communication with an internal control module, meaning it cannot safely operate until the connection is restored.
Your boiler has lost communication with an internal accessory or control component, which is preventing it from operating correctly.
Your boiler's internal communication system is experiencing a data connection failure, preventing it from operating correctly.
Your boiler's internal communication system is overloaded, preventing it from functioning correctly.
Your boiler's computer is reporting an internal configuration error, which means it cannot safely coordinate its various parts to start up.
Your boiler's internal computer system is having trouble starting up and cannot properly communicate with its internal control panel.
Your boiler's computer memory has lost or cannot recognise its unique identification number, which prevents it from starting up correctly.
Your boiler is currently running in a restricted safety mode because it has detected an unusual temperature difference between its internal sensors.
The boiler's internal memory storage is full, which is preventing the device from logging new data or diagnostic events.
Your boiler has reached its programmed time limit for running hot water and has temporarily stopped to prevent excessive usage or overheating.
Your boiler has detected a safety issue and has shut itself down completely to prevent damage or danger.
Your boiler has detected a disconnected sensor on the return pipe, which prevents it from accurately measuring the temperature of the water coming back into the system.
Your boiler has detected that the water temperature sensor on the return pipe is not providing a valid signal, preventing the system from heating correctly.
Your boiler has lost the signal from the sensor that monitors the temperature of the water returning from your radiators.
Your boiler has detected that the water returning through your radiators is too hot compared to the water it is sending out, causing the system to stop working to protect itself.
Your boiler has lost the connection to the temperature sensor for your hot water tank, meaning it cannot accurately tell if your water is hot enough.
Your boiler has detected an error with the temperature sensor for your hot water tank, meaning it cannot accurately measure or provide hot water.
Your boiler is repeatedly failing to keep its flame lit, so it has locked itself for safety to prevent a build-up of unburnt gas.
Your boiler has detected that the internal fan responsible for moving air and exhaust gases is spinning at the wrong speed, causing the system to stop working for safety reasons.
Your boiler has detected that hot water is flowing in the wrong direction or at the wrong temperature, causing it to shut down for protection.
Your boiler has failed to stay lit several times today and has locked itself out for safety reasons.
Your boiler has stopped working because it is receiving an external signal to pause, such as from an energy management system, a frost protection sensor, or a safety device.
Your boiler is having trouble communicating with an external control component, causing it to stop operating to ensure safety.
Your boiler's internal electronic control system has lost communication with the gas supply valve, meaning the boiler has safely shut down to prevent it from operating without proper control.
Your boiler has detected that a crucial internal safety component has been unplugged or has lost its electrical connection, so it has shut down to prevent unsafe operation.
Your boiler's internal communication system is experiencing a fault, causing the main control unit to lose connection with its internal components.
Your boiler's internal computer is experiencing a software memory error, meaning it has lost critical safety settings required to operate.
Your boiler has stopped working because it is unable to accurately read the temperature of the water flowing through it, likely due to a faulty internal sensor.
Your boiler has stopped working because it has lost the connection to the sensor that monitors the temperature of the water flowing through the system.
Your boiler has detected that the water inside the system has become dangerously hot and has shut itself down to prevent damage or overheating.
Your boiler has detected a disagreement between two internal temperature sensors, meaning it cannot reliably tell how hot the water inside is.
Your boiler has failed to light the flame five times in a row and has locked itself out for safety reasons.
Your boiler has detected a flame inside when it should be turned off, so it has safely shut itself down to prevent any risk.
Your boiler has detected that the internal fan responsible for venting exhaust gases is not spinning or responding correctly, so it has safely shut down to prevent unsafe operation.
Your boiler has detected a communication problem with the part that controls the gas supply, meaning it has safely shut down to prevent unsafe operation.
Your boiler has detected an internal software or communication error and has safely shut itself down to prevent damage.
Your boiler is currently taking a short break from operating, but it will attempt to restart itself automatically once the underlying issue resolves.
Your boiler has lost its connection to its external room temperature sensor, meaning it does not know the room temperature and cannot heat your home appropriately.
Your boiler's internal computer is having trouble talking effectively to its main controls, which is causing it to stop operating.
Your boiler is struggling to circulate water properly, causing the temperature difference between the water leaving and returning to the boiler to become too large.
Your boiler has detected that the water inside is heating up or cooling down much faster than it considers normal, so it has paused operation to prevent any internal damage.
Your boiler has detected that the water inside the unit has become dangerously hot and has shut itself down to prevent damage.
Your boiler has detected that the exhaust gases leaving the system are too hot, so it has safely shut itself down to prevent damage.
Your boiler is currently restarting itself, so please wait a few minutes to see if it begins operating normally again.
Your boiler is currently unable to start because it is waiting for its internal settings to be correctly finalised or registered.
Your boiler's computer has detected a configuration error, meaning it has lost its correct settings and cannot safely operate the heating or hot water.
Your boiler has encountered a digital configuration error, meaning the internal settings that control how it operates have become corrupted or are no longer recognised.
Your boiler’s internal electronic controls are failing to communicate correctly, meaning the system has locked itself out to prevent unsafe operation.
Your boiler has detected that water or exhaust gases are not flowing as freely as they should, causing it to throttle back its performance to prevent overheating.
Your boiler has detected a block and is preventing operation to ensure safe performance.
Your boiler is currently stuck in a waiting mode because it has not received the correct command from your thermostat or heating controller to start heating up.
Your boiler is struggling to detect the water flow correctly, which acts as a safety measure to prevent the internal components from getting too hot.
Your boiler is failing a mandatory internal health check as it prepares to start, which prevents it from firing up safely.
Your boiler's computer has encountered a configuration error where some of its internal settings have become corrupted or are no longer recognised.
Your boiler's internal computer is having trouble communicating with one of its internal control modules, causing the system to stop working as a precaution.
Your boiler has shut down because it keeps losing its flame while heating up and is unable to stay lit.
Your boiler has detected an internal communication error and has temporarily stopped operating to prevent further issues.
Your boiler has detected an internal safety issue during its regular self-check process and has locked itself out to prevent potential damage or unsafe operation.
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BoilerFaultCodes