BoilerFaultCodesYour boiler has switched itself off to prevent damage and is trying to show you a specific error code by flashing between the letter F and another number.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler is in lockout for a specific error. Display will be blinking, alternating with a number or letter to show which error is detected.
What causes this fault?
This fault occurs when the boiler’s internal control system detects a serious operational problem and shuts down for safety. The 'F' indicates a lockout state, which is triggered when a sensor or component fails to perform its specific task during the heating process. The most common reasons involve the boiler failing to light correctly or sensing an issue with the electrical circuit board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like F — no call-out fees, no surprises.
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