High Lockout
F10 on Glow-worm Flexicom sx

Your boiler has stopped working because a sensor that monitors the temperature of the water leaving the unit has failed or disconnected.

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 NTC fault

What causes this fault?

This fault occurs when the boiler's internal computer loses communication with the sensor that monitors the temperature of the water sent to your radiators. The most common reason is that the sensor has physically failed due to age or internal wear, though it can also be caused by a loose wire or moisture damaging the electrical connection.

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 →F11View →

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