High
d.24 on Vaillant ecoTEC sustain

Your boiler's internal water pressure sensor is telling the system that the water flow has stopped or the sensor itself is not detecting any movement, which usually prevents the heating from turning on.

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

Status of the pressure monitor: off=Not switched, on=Switched

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.24View →

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