High Lockout
4.7 on Ideal Vogue System

Your boiler has detected a problem with the internal sensor that measures the temperature of the water leaving the unit, preventing it from heating correctly.

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

Flow Thermistor Fault

What causes this fault?

This fault occurs when the boiler's control board loses communication with the sensor that monitors the temperature of the water heading to your radiators. It is usually caused by the internal sensor failing due to age or heat fatigue, though it can also be triggered by a loose electrical connection or moisture damange to the wiring.

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

4.8View →

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