High
Lockout on Baxi BBU 45/4

Your boiler has stopped running as a safety precaution and needs a manual restart to try and light the flame again.

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

This is indicated by the red light coming on at the back boiler control panel. Turn the control thermostat knob 'A' anti-clockwise to 'RESET' (OFF)... To restart the boiler, turn on the gas supply at the gas service cock and turn the control thermostat knob 'A' anti-clockwise to the 'Reset' position then clockwise to maximum. DO NOT ATTEMPT TO RELIGHT UNTIL AT LEAST 3 MINUTES HAVE GONE BY.

From this model's manual
Verified against the Baxi Bbu 45 4 installation & service 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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