BoilerFaultCodesYour boiler is alerting you to a specific problem, but the 'F' is just the prefix and requires the number that follows it to identify the actual issue.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler has a fault for a specific error. Display will show a number after the “F” to indicate which error is detected.
What causes this fault?
This fault occurs when the boiler's internal computer detects a mechanical or electrical failure that prevents it from operating safely. It is typically triggered by a specific component like the fan or gas valve failing to respond, or a sensor sending an incorrect reading to the main control board. Because 'F' is only a partial code, the boiler is waiting to display a secondary number that pinpoints exactly which part has stopped working.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 F — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Ideal Logic Combi ESP1 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.