30 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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Your boiler has lost the connection to the weather sensor outside your home, meaning it cannot automatically adjust your heating based on the outdoor temperature.
Your boiler is struggling to detect the movement of water inside the system, which is preventing it from heating your home or water safely.
Your boiler is struggling to accurately measure the temperature of the water returning to it, which prevents the system from heating your home properly.
Your boiler is struggling to detect the temperature of your hot water supply, so it has safely switched off your hot water to prevent an error.
Your boiler's internal computer is struggling to communicate with its control panel or thermostat, causing it to stop operating as a safety precaution.
Your boiler has detected that the water pressure inside your heating system is either too low or too high for it to operate safely.
Your boiler is automatically running a short seven-minute cycle to remove trapped air from the system after it detected low water pressure.
Your boiler has automatically shut down because its internal temperature has risen above safe operating limits.
Your boiler has stopped working because the water pressure inside the system has risen too high, likely due to a faulty filling loop or a system issue.
Your boiler has detected that there is not enough water in the system, so it is limiting its performance to protect itself.
Your boiler has detected that a small safety wire or bridge connection inside its control panel has come loose or is missing, preventing the system from starting.
Your boiler has stopped working because the internal fan required to safely vent exhaust gases is failing to turn on.
Your boiler has failed to light its flame after several attempts and has shut down for safety.
Your boiler has stopped working because it cannot properly regulate the air flow required for safe combustion.
Your boiler is struggling to pump water around your heating system correctly, so it has turned itself off to avoid overheating.
Your boiler has successfully completed an automated diagnostic or calibration test and is ready to return to normal operation.
Your boiler has successfully completed an automated diagnostic or calibration check and is simply returning to its normal operating state.
Your boiler is currently running an automatic air-purging cycle to remove trapped air from the system.
Your boiler is currently unable to detect the flow of water because the sensor responsible for monitoring it is providing an incorrect reading or has stopped communicating with the system, which will prevent your heating and hot water from working.
Your boiler is struggling to accurately measure the temperature of the water returning to it, which prevents the system from heating your home correctly.
Your boiler has lost the ability for its internal parts to 'talk' to each other, meaning it cannot start up or function until the communication is restored.
Your boiler has detected that there is either too little water circulating through the system or that the internal pump responsible for moving that water has stopped working.
Your boiler has switched itself off because it has become dangerously overheated.
Your boiler has detected that the water inside has become dangerously hot and has shut itself down to prevent damage or safety issues.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler's air circulation system has failed to start properly, so it has shut down to prevent unsafe operation.
Your boiler is failing to light the fuel inside because it cannot detect a flame, causing the system to stop trying for safety reasons.
Your boiler has detected that the internal fan responsible for safety and combustion is not spinning at the correct speed, so it has shut down to prevent any risk.
Your boiler has detected that hot water is flowing in the wrong direction or circulating much faster than it should be, causing the system to shut down for safety.
Your boiler has detected that the concentration of chemical protector added to your heating system to prevent corrosion and freezing is outside of the recommended range.
BoilerFaultCodes