BoilerFaultCodesYour boiler's computer memory card is experiencing a communication error or has failed during an internal update, causing the system to stop working.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Blocking during boiler chip card (BBC) update
What causes this fault?
This fault occurs when the boiler's main control board loses its connection with the small plug-in memory chip that contains the unit's specific operating instructions. It is usually triggered by a physical hardware failure on the chip itself or a data corruption error that happens while the system is trying to update its internal software.
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 UA-64 — 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.