Low
d.24 on Vaillant ecoFIT Pure 435

Your boiler is checking whether there is enough water pressure to run safely, but it hasn't yet reached the point of locking out with a permanent error.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

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

From this model's manual
Verified against the Vaillant Ecofit Pure 830 installation & service manual, page 30.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check the pressure gauge on the front of the boiler or under the casing.If the pressure is below 1.0 bar, use the filling loop to top it up to 1.5 bar.Ensure all radiator valves are fully open to allow water to flow freely.

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