BoilerFaultCodesYour boiler is still detecting a flame even after it has been told to turn off, which is a safety concern that requires a professional inspection.
Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now — this fault can be dangerous if ignored.
Technical description: Flame detection fault (flame presence for more than 5 seconds after burner stopped)
What causes this fault?
This fault occurs when the boiler's safety sensors continue to detect heat or electrical signals from a flame even after the gas should have been cut off. The most common reasons are a sticking gas valve that isn't closing fully, a damaged sensor probe that is sending incorrect signals, or a fault within the main control board.
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 F16 — 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.