BoilerFaultCodesYour boiler's internal computer brain hasn't been programmed correctly or has lost its memory, so it doesn't know how to operate your specific heating system.
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 main control board is either brand new and hasn't been set up yet, or has suffered a software glitch that wiped its memory. Without these specific instructions, the boiler doesn't know which model it is or how much gas it should be burning, so it shuts down for safety. This is usually triggered by a power surge or following a recent repair where a new part was installed.
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 F9 — 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.