High
F3 on Heatline Vizo Plus

Your boiler's internal thermometer has stopped working correctly, meaning the system can no longer monitor the water temperature and has shut down as a precaution.

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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