Medium
d.75 on Vaillant ecoFIT Pure 425

Your boiler is taking longer than it should to heat up your hot water tank, meaning the water may not be reaching the desired temperature efficiently.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Maximum cylinder reheating time

From this model's manual
Verified against the Vaillant Ecofit Pure 830 installation & service manual, page 31.
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 that your hot water cylinder thermostat is not set to an unusually high temperatureEnsure that any manual valves on the pipework leading to the cylinder are fully openVerify that your heating controls and programmers are calling for hot water correctly

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