High
6 flashes green on Baxi 800 Heat

Your boiler has detected an internal electronic error within its main control system that is preventing it from starting safely.

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.

What the manual says

Manufacturer manual

Miscellaneous - Internal fault in combustion control unit

Shared across the 800 Heat range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

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.

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Related fault codes

E119View →E133View →

All 12 fault codes on the 800 Heat

Seeing a different code? Every code this model can display, in one place.

1 flash green1 flash red2 flashes green2 flashes red3 flashes green3 flashes red4 flashes green4 flashes red5 flashes green5 flashes red6 flashes red

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