High Lockout
FO30 on Intergas Xtreme / Xclusive

Your boiler has stopped working because it cannot detect any water flowing through the system, meaning it cannot safely heat your home or 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.

Technical description

Sensor S3 fault

What causes this fault?

This fault occurs when the boiler's internal flow sensor fails to detect water movement when the pump is running. The most common reasons are a mechanical failure of the sensor itself, a blockage preventing water circulation, or a communication issue between the sensor and the main control board.

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

F031View →

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