BoilerFaultCodes.com
09 High Lockout

Your boiler has failed to fire up or complete its safety checks after several attempts and has now locked itself out for safety.

Call an engineer soon

Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Final fault code (Refer to section 7.11)

What causes this fault?

This fault occurs when the boiler's control system fails to detect a flame after multiple ignition attempts, causing the unit to shut down for safety. The most common reasons are a lack of gas supply to the burner, a build-up of soot on the ignition sensors, or a failure in the electrical signals sent by the main control board.

Typical repair cost £120-£350 (including labour)

DIY fix possible

Locate the mode selector switch on the front panel.Turn the switch to the 'OFF/RESET' position and wait for 10 seconds.Turn the switch back to either 'Hot Water Only' or 'Heating and Hot Water' to see if the boiler restarts.

Find a Gas Safe engineer

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