BoilerFaultCodesYour boiler has detected that its internal water temperature is too cold and is running automatically to prevent the pipes from freezing.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Frost protection device active (boiler will fire until return temperature of 10°C is reached)
What causes this fault?
This occurs when the sensors inside your boiler detect that the water temperature has dropped to a level where the pipes are at risk of freezing. To protect itself, the boiler automatically switches on to circulate and heat the water until a safe internal temperature is reached. This is a normal safety feature rather than a breakdown, usually triggered by the boiler being located in a cold area like a garage or loft.
This code is almost exclusively seen during the winter months or during sudden overnight cold snaps when external temperatures drop toward freezing.
DIY fix possible
Ensure the boiler power remains switched onCheck that the gas supply is activeWait for the boiler to finish its heating cycle and the 'F' code to disappear
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A boiler cover plan would cover faults like F — no call-out fees, no surprises.
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