BoilerFaultCodesYour boiler's main control board has lost its programmed settings and no longer knows how to operate the specific model it is installed in.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Unconfigured PCB
What causes this fault?
This fault occurs when the boiler's central brain, the printed circuit board, suffers a memory failure or loses its identity settings. The most common reason is a sudden power surge or a component failure on the board that wipes the specific software instructions required to run your boiler safely.
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 F09 L09 — 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.