Hot Water System Problems

[-scrumpy-]

Hi All,

I received some great advice to a previous post: //www.diynot.com/forums/viewtopic.php?t=45962

Which explained that I had air in my power shower feed. I followed the advice in that post, and now I have a different problem. To recap, I have a hot water cylinder with the hot feed coming out of the side of the tank, towards the top. This feed connects directly to a thermostatic blending valve. The output of this valve feeds the hot water supply (power shower pump, taps etc.).

The cold feed to the mixer valve now comes directly from the cold water tanks in the loft. This gave me good pressue in the shower, and eliminated bubbles (with the held of an airlock valve too).

Problem we then had was that the water in the tanks in the loft started heating up - the hot water from the cylinder was passing through the mixer valve, and up to the tanks.

So, a non-return valve was put in the feed from the cold tanks to the mixer valve. This has stopped the water in the cold tanks heating up. When the shower is on, it pulls water through the mixer valve, and it mixes hot and cold to give a good temperature.

However (!!), when I turn the any of the hot taps on, it doesn't open the non-return valve, so I draw off hot water straight out of the tank. As we have solar heating, the hot water can be scalding (hence the need for a mixer valve).

It seems the non-return valve has worked in that it doesn't heat up the cold water in the tanks anymore, but the valve doesn't open when we turn the hot taps on.

Does anyone have any ideas or suggestions?

Many thanks again for any advice!

Nick

 

[ChrisR]

If you go to bes.ltd.uk and do a search for product 7463 you get a page of options
If you've put in a double check valve, take it apart and remove one of the check 's cos you only need one. (Long pliers and a woodscrew will have it out)
You could put in a bigger diameter (single) check valve - they have less resistance as they go bigger,
or you could use the gravity-swing variety as 7463, which has to be the right way up, ie sideways but opens easily.

 

[-scrumpy-]

Thanks for the reply - my local plumber installed the valve, so I'll have to double check (no pun intended!) with him what they fitted. Sounds like I need to ask them to fit a swing check valve horizontally, as that looks like it will do the trick.