High Lockout
F06 on Intergas Rapid 25

Your boiler has stopped working because it cannot communicate with the internal sensor that monitors your hot water temperature.

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

S3 sensor open circuit

What causes this fault?

This fault occurs when the boiler's main control board loses its connection to the sensor that measures hot water temperature. The most common reason is that the sensor itself has developed an internal electrical failure or the wiring connecting it to the system has come loose. Because the boiler no longer knows how hot the water is, it shuts down as a safety precaution to prevent overheating.

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

F02View →F05View →F15View →

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