High Lockout
19 on Glow-worm 30ci Plus

Your boiler has detected that a temperature sensor has lost physical contact with the internal pipework, meaning it can no longer monitor heat levels 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 not connected to pipe

What causes this fault?

This fault occurs when the temperature sensor responsible for monitoring your heating water becomes physically detached from the pipe it is meant to sit on. The most common reason is a snapped or weakened metal retaining clip, though it can also be caused by excessive vibration or a loose wiring plug that has vibrated free over time.

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

F6View →F14View →

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