High Lockout
F003 on Intergas Xtreme / Xclusive

Your boiler has shut down because the internal gases leaving the system have become too hot, which is a safety feature to prevent damage to the internal components.

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.

Technical description

Flue gas temperature too high

What causes this fault?

This fault occurs when the internal safety sensor detects that the exhaust gases have reached a dangerously high temperature, often due to a lack of water flow or a build-up of debris inside the heat exchanger. It essentially means the heat being produced isn't being carried away into your radiators efficiently enough, causing the internal components to overheat. In some cases, it can also be triggered by a faulty sensor providing an incorrect reading or damaged internal insulation.

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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Related fault codes

F002View →

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