Vailant eco tech plus 831

Mike1969 · 5 Oct 2025

Hi, new on here so please be gentle

I have a Vaillant eco tech plus 831 which is around 10 years old. Recently when i shower or run the hot water which the temperature is set at 65 deg then it runs fine and the temp sits around 66ded, but some days when i run the hot water/shower the temp starts at around 65 deg but then slowly drops to around 49deg and sits there.

When i run the hot water the radiators are not getting warm.

any help would be much appreciated as it seems to be intermittent.

thanks

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Vailant eco tech plus 831

Mike1969

DIYnot Local

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