Help with manual mixer shower prob

[joni2008]

Hi chaps, Would appreciate some help.

I've installed a manual mixer shower on a open vented system, only to find out later that the shower doesn't work properly. You will already know that this is because the cold feed upstairs is linked to the rising main and the hot is fed from the loft storage tank - giving (unbalanced feeds) I've done some reading on the forums and tried to gather as much information as possible without been a pest.

I was advised to try a pressure reducing valve on the cold feed - This i did and that didn't work - Waste of £35 - The water on the shower will not get to a reasonable temperature, i'ts either very hot or when trying to mix a little cold goes freezing.

My other option as advised was to do it the right way and connect the cold water upstairs to the cold storage tank. I'm no plumber but will have a go at most things if i feel confident and have enough information prior to the crunch.

Question - Is it a big job ? My consern here is that the Water storage tank is not a large one and this may be because it's only supplying the hot water - Also it's only filling up a third of the way before the valve cuts it off. If i did rig this up then it may be not big enough for the demand of both hot / cold. I would really like to get this sorted for my mother.

Thanks for any help

[bbb]

If you do decide to tackle this then make sure that the cold feed to the shower coming out of the cistern is below the hot feed, other wise you could end up scalding whoevers in the shower

[joni2008]

Cheers i herd that from someone else too - why is this ?

[ProffesorPlumb]

The water supply would cut off to the cold feed showert first, as the lower cold feed to the HWC will continue to feed and therefore continue to heat up. This means there would not be a hot and cold mix in the thermo valve.

You need a 50 gallon Cistern in the roof to feed a power shower and a HWC, especially if the shower is pumped.

Try and install the cold feed to the shower at the lowest point of the cistern, with the feed to the HWC 150mm above that.

You will also need a minimum head from the tank to shower outlet of 1m, or 150mm if it is a pumped shower.

Good luck