High Lockout
20 on Intergas Rapid 25

Your boiler has detected a problem with its internal temperature sensors, which means it cannot accurately monitor the water temperature and has stopped working for safety.

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 fault S2

What causes this fault?

This fault occurs when the boiler’s return sensor, which monitors the temperature of the water coming back from your radiators, sends an incorrect or missing signal to the main computer. The most common reason is that the sensor itself has developed an electrical internal failure, or the wiring connecting it to the control board has become loose or damaged.

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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