34 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
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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 |
|---|---|---|
| 47-349-09 | INSTINCT 24 | 2015–present |
| 47-349-10 | INSTINCT 30 | 2015–present |
| 47-349-11 | INSTINCT 35 | 2015–present |
| 47-349-68 | INSTINCT2 24 | 2019–present |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
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Your boiler has detected a problem with the internal sensor that monitors the temperature of the water as it leaves the unit, causing it to shut down as a precaution.
Your boiler has detected a problem with the sensor that monitors the temperature of the water returning from your radiators, preventing it from heating your home correctly.
Your boiler's internal computer brain hasn't been set up correctly to tell it which model it is, meaning it doesn't know how to operate safely.
Your boiler has detected that water is not moving through the system properly, which has caused it to stop working to prevent overheating.
Your boiler has detected that there is not enough water circulating through the system to operate safely, which is usually caused by low water pressure or an air lock.
Your boiler has detected an internal fault that needs technical attention, but it has not specified exactly which component is failing yet.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler has lost its gas supply or cannot detect a flame, meaning it cannot stay alight to provide heating or hot water.
Your boiler has started an ignition sequence but the flame has either failed to light or gone out unexpectedly, meaning it cannot provide heat or hot water.
Your boiler has detected an issue with the electrical fan which is preventing it from safely starting up to provide heating or hot water.
Your boiler's internal thermometer that monitors the water temperature leaving the unit has stopped working correctly, causing the system to shut down for safety.
Your boiler has detected a problem with the sensor that monitors the temperature of the water coming back into the unit, causing it to stop working as a safety precaution.
Your boiler is having trouble communicating with the heat sensor located on the outside of your house, which helps it decide how hard to work based on the weather.
Your boiler has detected that the electricity supply coming into your home is at a lower voltage than it needs to operate correctly.
Your boiler's internal computer brain is confused or has lost its settings, causing it to stop working for safety reasons.
Your boiler's internal computer has lost its settings or there is an electrical fault, meaning the system has shut down for safety.
Your boiler's internal computer has encountered a critical error and can no longer control the heating system safely.
Your boiler's internal computer has suffered a critical error and can no longer control the heating or hot water safely.
Your boiler has stopped working because it has detected an unusual temperature difference between the water leaving and returning to the unit, suggesting a sensor error or a flow issue.
Your boiler is failing to stay lit, which means the system cannot get the heat it needs to provide you with hot water or warming for your radiators.
Your boiler's water pump is struggling to circulate water because it is stuck or jammed, which means the system cannot heat your radiators or tap water.
Your boiler is overheating because the water isn't moving through the system quickly enough to be cooled down.
Your boiler has stopped working and locked itself for safety because it has detected a specific internal fault or failed to fire correctly multiple times.
Your boiler has sensed it is getting too hot and has shut itself down as a safety precaution.
Your boiler is failing to light the gas to start the heating or hot water process, and has locked itself for safety after 5 attempts.
Your boiler has detected an issue with the sensor that monitors the temperature of the water leaving the unit, causing it to stop running for safety.
Your boiler has detected an issue with the sensor that monitors the temperature of the water leaving the unit, causing it to shut down for safety.
Your boiler has detected an issue with a temperature sensor that monitors water returning to the unit, causing it to stop running for safety.
Your boiler has detected a problem with the sensor that monitors the temperature of the water returning to the unit, causing it to shut down for safety.
Your boiler has sensed a flame inside the unit when there shouldn't be one, causing it to shut down for safety purposes.
Your boiler's internal computer is having trouble reading its own settings and has shut down as a precaution.
Your boiler's main internal computer has developed a malfunction and is no longer able to control the system.
Your boiler has been manually reset too many times in a short window and has temporarily locked itself to prevent further strain or damage.
Your boiler is struggling to keep its flame lit, which means the system has safely shut down to prevent unburnt gas from building up.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes