BoilerFaultCodesYour boiler has detected a problem with its gas supply system or internal control valve, meaning it cannot safely ignite to provide heating 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: Gas valve error – wiring disconnected or faulty gas valve
What causes this fault?
This fault occurs when the boiler’s main control board loses communication with the gas valve, which is the component responsible for letting fuel into the burner. The most common reason is either a loose or damaged connection in the internal wiring, or the gas valve itself has suffered an electrical mechanical failure and can no longer open.
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 A16 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
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.
Affiliate links — we may earn a commission at no extra cost to you.