Central Heating - Losing pressure

24 Oct 2017
Reaction score
United Kingdom
Hi All,

I have seen a few similar threads, but thought it best to start a new one as they spoke about megaflow systems and we have a Joule Unvented cylinder.

We had the unvented cylinder installed a few months ago and all the pipework redone in the house, however there was a few months gap before we had the new rads fitted, whilst we had the plastering done.

The system has never really worked properly, I fill it with the filling loop and after a few hours it is back to almost zero.

I know that it could be a leak but I have looked everywhere and have seen no sign of any leaks. This has been going of for a few months now so I think I would have noticed that much lost water (but I could be wrong).

This may be normal, but sometimes it sounds like the boiler drains, and a load of water goes down a pipe from the boiler, outside and under ground.
I am not sure if this is happening but it might give a clue?

Any ideas about why this is happening would be much appreciated.
Sponsored Links

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