Plumbing two new valves 1 head each into existing shower stall.

[EOppegaard]

Hey everyone.

I have an existing shower stall which I am planning on adding two additional valves, each with their own head. Originally we looked at putting in a diverter valve, however we would like to be able to independently control the temperature per head. One will be a standard wall mounted shower head, the second will be a rainshower head coming out of the ceiling. Both are 2.5GPM.

In order to match the existing valve we went with two KOHLER Rite-Temp 1/2 in. Brass NPT x NPT Pressure-Balancing Valves (K-304-KS-NA). We luck out that the water heater is on the opposite side of the wall where we are installing the new valves. The plan is to tap into the existing cold and hot water lines (1/2 CPVC) from the water heater for both of the new valves.

The question I have is what is the best practice to run from the water heater to each of the new valves. They will both be mounted in the same wall, one above the other. One of the plumbers I originally talked to about the job had mentioned the need to create a pressure balancing loop, however I thought this was only for outlet flows, not for inlets. Frankly making a loop didn't make sense to me on the inlet side.

The plan right now is to run a single 1/2 CPVC line for both hot and cold supply from the water heater. Install the first valve, each with a T on both supply inlets, and then pipe the second valve on the other end of the T.

We will be running both valves at the same time, or at least that possibility will present itself.

I do not know the exact static pressure inside the house, however I will say we can run the washer, shower, and flush the toilet without any obvious drop in pressure. It is a single story house, the shower is located on the opposite end of the home from the main water supply in.

Any help would be appreciated.

Thanks!

-Eric

[jadnashua]

A 1/2" supply pipe can realistically supply about 5gpm with copper - cpvc slightly less. Now, because you have both hot and cold running some, you can get more through an individual valve, but not much due to its internal passage sizes. So, you may want to run 3/4" and reduce to 1/2" for the second valve. For probably less money than two complete valve assemblies, one with an appropriate diverter valve may be less expensive.

[hj]

If this is a "shower for two", then having both valves in the same location does not seem very "user friendly".