High Lockout
UA-67 on Daikin D2CND

Your boiler is unable to start because it cannot detect its internal memory chip, which contains the essential programming it needs to operate.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Boiler chip card (BCC) is missing

What causes this fault?

This fault occurs when the boiler's control system loses its connection to the small memory chip that stores its identity and safety settings. The most common reason is that the chip has vibrated loose from its socket, or the internal circuitry on the main control board has failed and can no longer read the data.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer
Search the official register →

Related fault codes

UA-66View →

Related guides you might find useful

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →