High Lockout
F19 on Glow-worm 30ci Plus

Your boiler has detected that a temperature sensor has come loose from its pipe, preventing it from reading the system's heat 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

Central heating NTC unclipped

What causes this fault?

This fault occurs when the temperature sensor physically detaches from the heating pipework or becomes loose enough that it can no longer take an accurate reading. The most common reason is a weakened or broken metal retaining clip that has failed due to age or vibration, causing the sensor to drift away from the heat source.

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

F1View →F2View →F6View →

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