High
F.75 on Vaillant ecoFIT Pure 435

Your boiler is not detecting the necessary water movement to safely ignite and provide heating or hot water, usually because the internal system pressure is too low or a sensor is blocked.

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

Fault: No pressure change detected when starting the pump

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

F.22View →F.73View →

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