BoilerFaultCodesYour boiler thinks a flame is burning even though it shouldn't be, 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: False flame lockout
What causes this fault?
This fault occurs when the boiler's internal sensors detect a flame after the burner has been told to switch off, or before it has even started. It is usually caused by a faulty sensing probe sending an incorrect signal to the main control board, or a leak inside the unit that has allowed moisture to interfere with the electrical components.
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 L6 — 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.