BoilerFaultCodesYour boiler's internal computer parts are struggling to talk to each other, preventing the system from starting up.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Electronic control board (PCB) communication error.
What causes this fault?
This fault occurs when the main electronic brain of your boiler loses its connection with the internal components it needs to control. It is usually caused by a physical break in the wiring or a burnout of the circuitry on the printed circuit board itself, preventing the boiler from receiving the signal to start heating.
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 F11 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Xtramax HE is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.