BoilerFaultCodesYour boiler's internal memory chip is not communicating correctly with the main control board, 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: Boiler Chip Card (BCC) activation fault
What causes this fault?
This fault occurs when the boiler's main control board cannot read the data from the small memory chip that tells it exactly how to operate. This is usually caused by a loose connection where the chip is plugged in, or a physical failure of the chip’s internal circuitry after years of heat exposure.
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 C0 — 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.