BoilerFaultCodesYour boiler has encountered a general operation error that is usually caused by a sudden interruption to the gas or electricity supply.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Fault Code (see section Fault Finding)
What causes this fault?
This fault occurs when the boiler's internal computer detects a sudden break in the supply of gas or electricity during operation. It is often triggered by an external factor like a temporary power cut, a gas meter issue, or a component failure that prevents the burner from lighting safely.
DIY fix possible
Check if other gas appliances in your home, such as a hob, are working correctlyEnsure your pre-payment meter (if applicable) has creditPress the 'Reset' button on the boiler control panel and hold 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 F — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Ultracom 24cx 30cx 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.