BoilerFaultCodesYour boiler is unable to correctly control the supply of gas it needs to create a flame, causing the system to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Gas mechanism fault
What causes this fault?
This fault occurs when the boiler's control board fails to communicate effectively with the gas valve, meaning the system cannot safely regulate the fuel flow. The most common reason is an internal electrical failure within the gas valve itself or a fault on the main circuit board that prevents it from sending the correct signals. In some cases, damaged or loose wiring between these two major components is responsible for the breakdown.
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 15 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Xtrafast 96 120 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.