High Lockout
06 on Glow-worm Ci Plus

Your boiler has detected a problem with the sensor that monitors the temperature of the water leaving the unit to heat your radiators.

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 flow NTC fault

What causes this fault?

This fault occurs when the internal sensor responsible for monitoring the heat of the water going to your radiators fails or sends an unreadable signal. The most common reason is that the sensor has physically degraded over time or a small leak has caused corrosion on the electrical connections. Without an accurate temperature reading, the boiler 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

F01View →F05View →F08View →

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