High Lockout
E06 on Remeha Avanta Plus 35c

Your boiler's internal computer has encountered a critical communication error and can no longer safely operate the heating system.

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

Internal control unit error

What causes this fault?

This fault occurs when the boiler's main control board suffers an internal electronic failure, preventing it from processing data correctly. It is often caused by a component on the circuit board wearing out over time or a loose connection in the wiring that links the controls together. Because the 'brain' of the boiler can no longer guarantee safe operation, it shuts down the system entirely.

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

E04View →E05View →E11View →

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 →