High Lockout
C2 on Ideal Logic+

Your boiler's internal memory card has developed a communication fault, meaning the control system cannot verify the specific settings for your model.

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) fault

What causes this fault?

This fault occurs when the boiler's main control board loses its connection with the small memory chip that stores your appliance's specific tuning profile. The most common reason is that the chip card has vibrated loose, failed electronically, or the main circuit board itself can no longer read the data required to operate safely.

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

C0View →

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 →