High
F3 on Heatline Vizo 24

Your boiler has lost the ability to measure the temperature of your hot water, which usually means it won't provide hot water to your taps or showers.

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

Domestic Hot Water (DHW) Sensor (NTC) Fault

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 →F4View →

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