Low
d.77 on Vaillant ecoFIT Pure 435

Your boiler is notifying you that it is currently prioritising reheating your hot water cylinder at its maximum power setting.

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

Max. cylinder reheating

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

Wait for the hot water cylinder to reach its target temperatureCheck your hot water cylinder thermostat isn't turned up unnecessarily highOnce the water is hot, the boiler will automatically return to normal heating mode

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