Ariana Orellana asked ... Code?    |    Lynnie asked ... BT Studio 4500 cordless telephone?    |    David Dawes asked ... How to recoil the starter spring - Champion R484TR?    |    peter high asked ... How can I set time on my Neff oven?    |    Michael asked ... Mountfield empress drive belt?    |    Click here to ask your question

Valiant thermostat , BMU-Err ?

Vaillant thermostat and boiler with the error message on thermostat
What do I do?
Louise, November 2016
Water pressure in system too low, add water watching pressure indicator to achieve over 0.9bar.

Peter, January 2023
link Click here to see other fixes for Vaillant.