Weismann Vitodens 100 boiler low pressure

12 Jan 2014
Reaction score
United Kingdom
Hi all,
Our boiler is a Weismann Vitodens 100. We only moved into this house in Nov so we're not sure of its age, but we were assured by the old owners that it had been serviced regularly. We came back from a wedding this afternoon to find a low pressure warning (0.5 bar) and the reset light flashing, so no hot water or heating.

I've read elsewhere on the forum that to increase the pressure you let water through the valves on the filling loop, but I can't find the filling loop on my boiler from the descriptions and photos on other threads. Can anyone help with which valves are the correct ones here, if visible at all?

If it's awkward I can always call in a professional, just trying to save some time as it's Sunday afternoon and it's cold!


Sponsored Links
looks like it could be the pipe underneath. the one connected second from the right (cold inlet) and cant tell but also connected to the pipe on the far left?? (return). with the black and yellow lever valve to fill the system. not a regulation filling loop if so.
You were right holty, got a plumber out today on the emergency home cover we have with Halifax and that was it. It's all fixed now and we know what to do for next time.
great you got it sorted. might be worth having a proper service. by someone who knows this boiler. id personally have the burner out and have the jammy slapper sorted. nuisance problem on these. also check the expansion vessel. these boilers were called the dover boilers. made for the english market. and could be problomatic. seen quite a few when i did there warranty work.
Sponsored Links
There should not be a 'next time' the pressure is not supposed to drop, unless you are bleeding radators. You may have a slight leak somewhere

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local