High
S3 on Ideal Harrier GT

Your boiler has detected an issue during the ignition process and has shut itself down for safety, meaning you currently have no heating or hot water.

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

Burner lock indicator. Feeds signal from lockout terminal on burner control box to lock out indicator on boiler control panel.

From this model's manual
Verified against the Ideal Harrier Gt 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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