bathroom refit - hot gravity fed, cold mains fed

29 Feb 2008
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United Kingdom
Hi there....

I'm in the process of refitting my bathroom and have the situation where the cold feeds to the sink/bath and toilet are all from the mains feed.

The hot water is gravity feed (water tank in loft and hotwater cylinder in the bathroom)

Putting in a shower I presume I am going to have problems of balancing between the mains cold and gravity hot.. and have the problem of tap turned on elsewhere (kitchen, garden) that I'll get scolded!

Can I get away with putting an isolator in the cold feed to the shower and using the isolator part closed to regulate the flow.

I presume ideally that gravity fed cold is actually the better way to go?
If I wanted to run both hot and cold as gravity fed can I tee from the cold inlet from the hotwater tank... or is it better to run a second line directly from the cold water storage tank?

Thanks for your comments.
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you could either have an electric shower (mains cold feed only) or take a separate cold feed from your cold water tank for your gravity feed cold and a surrey flnage from the top of your hot water cylinder for your gravity hot - that way you will get an equal balance of pressure.

how big is your cold water tank? it should be large enough for this...

or you could actually fit a venturi shower valve - mains pressure hot and cold water this way (or nearly as good as)..
don't fit a isolation valve to restrict the water as this only restricts the flow not pressure.
as stated run shower feeds seperate to any other supply then you won't get any problems.
you want equal pressure on your hot and cold for your manual mixer shower, but if you ever have cold mains and gravity hot then you must have a double check valve on the 2 supplies, eg with a kitchen mixer tap.
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Hi there,

You could judt get a "venturi" shower mixer. This uses the pressure of the main to pull the hot thru the mixer faster.

only possible to have a venturi shower mixer if the rising main passes through your airing cupboard though isn't it ....?

Why do you say that.

If it going above the bath, just take the feeds from the supplys already in place.


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