Emergency
F5 on Heatline Sargon 30

Your boiler has detected a fault with a safety sensor that monitors the temperature of the gases leaving your flue, meaning the boiler has shut down to prevent overheating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Combustion product (flue) temperature probe damage

From this model's manual
Verified against the Heatline Sargon 30 installation & service manual, page 26.
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 emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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