21 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 |
|---|---|---|
| 47-364-17 | Compact 25A | 2013–present |
| 47-364-18 | Compact 29A | 2013–present |
Tap any card for details
Your boiler has detected an internal safety issue, likely involving overheating or a ventilation problem, and has automatically shut down to prevent damage.
Your boiler has entered a temporary standby mode, which often happens if the system is waiting for the room thermostat to request heating or a hot tap to be opened.
Your boiler has failed to light the flame needed to produce heat or hot water, and it has locked itself out for safety.
Your boiler has detected that it is running too hot and has safely shut itself down to prevent damage.
Your boiler is struggling to detect that the internal fan, which clears exhaust gases, is spinning correctly.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler is struggling to detect the temperature of your hot water, so it has stopped providing it to prevent the system from overheating.
Your boiler is not reading its internal water temperature correctly, causing it to shut down to prevent overheating.
Your boiler is struggling to accurately read the temperature of the water returning to it, meaning it cannot reliably heat your home or water.
Your boiler has detected an issue with the sensor that monitors the temperature of the gases leaving your flue, causing it to shut down for safety.
Your boiler has detected a flame inside the unit when it was supposed to be turned off, so it has safely shut itself down to prevent a hazard.
Your boiler's internal computer is receiving an unexpected temperature reading from a sensor, which has caused it to stop working for safety reasons.
Your boiler is completely unresponsive and failing to receive any electrical current, meaning it cannot operate your heating or hot water at all.
Your boiler has detected an internal error and has safely shut itself down to prevent any damage or danger.
Your boiler has paused because it has detected a temporary issue, likely due to low water pressure or an intake problem, and is waiting for the condition to clear.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler has encountered a permanent safety lockout and has stopped working to protect itself.
Your boiler has likely overheated, causing a safety switch to trip and shut down the system to prevent damage.
Your boiler has stopped working because it couldn't light the flame correctly or has detected it is running too hot.
Your boiler has detected a very brief disruption in its normal operation and is attempting to reset itself automatically.
Your boiler has entered a test mode and is currently unable to provide normal heating or hot water.
Not faults — these are normal operating states. Tap to expand.
Monthly cover means no unexpected bills when your boiler breaks down.
Affiliate links. We may earn a commission at no extra cost to you.
BoilerFaultCodes