High
Ignition lockout on Halstead Ace 100

Your boiler has stopped working because it failed to light the flame, which often happens due to a simple supply issue or a temporary glitch.

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

If the burner fails to light within the technical time limit, the 'lockout' indicator (red LED) will illuminate. This can be reset by turning the control knob to 'Reset' for a few seconds.

From this model's manual
Verified against the Halstead Ace 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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