BoilerFaultCodesYour boiler has sensed a drop in temperature and is temporarily heating itself up to prevent the internal 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: The boiler is operating in frost mode
What causes this fault?
This occurs when the sensors inside your boiler detect that the water temperature has dropped below 5°C. To protect itself from damage, the boiler automatically fires up to circulate warm water until the internal temperature reaches a safe level. This is a normal safety feature rather than a mechanical breakdown.
This code is almost exclusively seen during winter or periods of extreme cold when temperatures drop near freezing.
DIY fix possible
No action is required; this is a normal safety function.The 'F' will disappear once the boiler reaches a safe temperature.Ensure your external condensate pipe is insulated to prevent it from freezing in cold weather.
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A boiler cover plan would cover faults like F — no call-out fees, no surprises.
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