High Lockout
F.73 on Vaillant ecoTEC exclusive

Your boiler's internal sensor that monitors water pressure has lost electrical contact or has failed, causing the system to stop working for safety.

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:Waterpress.sensor Interruption/shortcircuitofwaterpressuresensor,interruption/short circuittoGNDinsupplylinetowaterpressuresensororwaterpressure sensordefective

What causes this fault?

This fault occurs when the boiler's control board loses the electronic signal from the sensor that monitors internal water pressure. The most common reason is that the sensor itself has developed an internal electrical fault or the wiring connecting it to the main computer has become loose or damaged. Without this data, the boiler shuts down to prevent itself from firing while potentially dry.

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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