BoilerFaultCodesYour boiler has started an ignition process successfully but then lost the flame, meaning it cannot stay lit to provide heat or hot water.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flame Loss
What causes this fault?
This fault occurs when the boiler's control system detects that the flame has gone out unexpectedly after it was successfully lit. It is usually caused by a dirty or worn-out sensor that can no longer 'see' the flame, or an inconsistent flow of gas preventing a stable burn. In some cases, external factors like a blocked flue or debris in the burner can also cause the flame to flicker and fail.
This fault is more common during extreme cold spells, as freezing temperatures can cause the external condensate pipe to block, backed-up water then floods the combustion chamber and extinguishes the flame.
DIY fix possible
Check if other gas appliances, like a cooker hob, are working to ensure gas is being supplied to the property.Verify that your gas meter has credit if you use a pre-payment meter.Reset the boiler by turning the control knob to the 'RESET' position and holding for five seconds.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like F02 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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