34 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 47-583-29 | Advance Plus 25C | 2012–present |
| 47-583-30 | Advance Plus 30C | 2012–present |
| 47-583-31 | Advance Plus 35C | 2012–present |
| 47-583-43 | ADVANCE 25C | 2017–present |
| 47-583-44 | ADVANCE 30C | 2017–present |
| 47-583-45 | ADVANCE 35C | 2017–present |
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Your boiler is notifying you that it is due for its regular annual service or scheduled maintenance check-up.
Your boiler is struggling to light its burner or cannot detect that a flame has been successfully lit, preventing it from heating your water.
Your boiler has failed to light the flame, which means your heating and hot water will not work until the system is reset or the gas supply is restored.
Your boiler has entered a lockout state to prevent further damage or safety risks, usually following a failed ignition or a recurring internal error.
Your boiler has tried to light several times but failed, so it has shut itself down for safety.
Your boiler has switched itself off because it has detected that the water inside has become or is becoming too hot.
Your boiler has stopped working as a safety precaution and needs to be reset, but if the issue persists, a professional will need to investigate an internal fault.
Your boiler has detected that there is either not enough water in the system or the water isn't moving through the pipes correctly.
Your boiler has detected that there is either not enough water in the system or the water isn't moving through the pipes properly.
Your boiler has detected an issue with the internal air circulation system, which is preventing it from igniting safely.
Your boiler has detected a problem with the fan that safely removes exhaust gases, meaning the system has shut down for safety.
Your boiler is having trouble measuring the temperature of your hot water, which usually results in the water being stone cold or not reaching the right temperature.
Your boiler's central heating sensor has stopped working correctly, which means the system cannot accurately measure how hot the water is for your radiators.
Your boiler is struggling to accurately measure the temperature of your hot water, which means it has stopped providing hot water to prevent overheating.
Your boiler's hot water sensor has failed, meaning the system doesn't know how hot your water is and will likely stop producing hot water for showers and taps.
Your boiler is struggling to communicate with the outside temperature sensor, which helps it run efficiently.
Your boiler's outside temperature sensor is either broken or sending a wrong signal, which affects how efficiently the heating adjusts to the weather.
Your boiler has detected that a sensor monitoring the temperature of the exhaust gases is not working correctly, causing the system to shut down for safety.
Your boiler has detected that a sensor monitoring exhaust gas temperatures is faulty or has disconnected, causing the system to shut down for safety.
Your boiler has detected that the exhaust gases are becoming too hot, so it has safely shut itself down to prevent damage or overheating.
Your boiler is failing to detect a flame, which means it cannot light safely to provide heating or hot water.
Your boiler has sensed a problem with the internal sensor that monitors the temperature of the water returning from your radiators.
Your boiler has detected that a sensor monitoring the temperature of the water coming back from your radiators is not working correctly.
Your boiler has detected that the water is getting too hot too quickly because it isn't circulating through the system properly.
Your boiler has sensed that water is becoming too hot too quickly, usually because it cannot circulate correctly through your radiators or pipes.
Your boiler has detected that water isn't moving through the system properly or there is a lack of water, causing it to overheat and lock itself for protection.
Your boiler has detected that water isn't moving through the system properly or there is a lack of water pressure, causing it to overheat and lock itself for 10 minutes.
Your boiler is having trouble measuring the temperature of the cold water coming in, which may affect how well it heats your hot water.
Your boiler's hot water sensor has stopped working correctly, which may cause issues with the temperature of your baths and showers.
Your boiler is trying to start but cannot sense the flame required to heat your water, so it has shut itself down for safety.
Your boiler has shut down because it has detected an electrical connection issue or an internal wiring conflict within its control system.
Your boiler has lost power or hasn't had its model type correctly configured in the internal computer.
Your boiler is notifying you that the water pressure has dropped too low and the system needs to be topped up.
Your boiler has reached an excessively high temperature while trying to provide hot water and has shut down as a safety precaution.
Not faults — these are normal operating states. Tap to expand.
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BoilerFaultCodes