High Lockout
E.02 – .16 on Baxi 200 Combi (range)

Your boiler has experienced an internal electronic failure or a communication error between its main control components.

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

Permanent fault caused by channel service unit (CSU) time-out or printed circuit board (PCB) damage.

What causes this fault?

This fault occurs when the boiler's internal computer system suffers a critical communication failure or a physical hardware breakdown. It is typically caused by a malfunctioning main circuit board that can no longer send or receive signals correctly, or damaged internal wiring that has interrupted the connection between components. Essentially, the 'brain' of the boiler has stopped working, meaning it can no longer safely control the heating process.

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 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 →