High
F64 on Heatline Vizo 24

Your boiler is struggling to accurately read the water temperature, causing it to shut down for safety because the readings are changing too quickly.

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

Rapid fl uctuation of return or fl ow heating sensor.

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

F63View →F65View →

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