BoilerFaultCodesYour boiler's main internal computer has developed a critical software or hardware failure and can no longer control the heating or hot water safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Replace PCB.
What causes this fault?
This fault occurs when the boiler's central control board suffers a hardware failure, often due to an electrical surge or moisture ingress. Over time, heat stress or liquid from a small internal leak can damage the delicate circuitry, leading to a total communication failure between the 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 PCB FAULT — 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.