High Lockout
F003 on Intergas Xclusive 24

Your boiler has detected that the exhaust gases are getting too hot, so it has shut down as a safety precaution to prevent internal damage.

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 is too high.

What causes this fault?

This fault occurs when the internal heat exchanger cannot transfer heat into the water efficiently, causing the waste gases to reach a dangerous temperature. The most common reason is a buildup of limescale or debris inside the heat exchanger, but it can also be caused by a faulty sensor or a damaged burner seal allowing heat to escape where it shouldn't.

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 →F005View →

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