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doitright1st · May 1, 2009, 07:45 AM

I have about 80 psi water pressure in my house. I have 1/2" water lines stubbed out at my master shower. I want to place a multiple outlet shower with main showerhead (2.5 gpm), a hand shower (2.5 gpm) and possibly 2 - (2.5 gpm) body sprays. I am using a valve that will only mix two at a time so the most that can be turned on at once would be the regular shower and the 2 body sprays for a total of 7.5 gpm delivered at once. The question I have is; will I have enough water volume to sustain all these outlets?

massplumber2008 · May 1, 2009, 03:49 PM

Hi Doitright1st:

Best bet here would have been to install a 3/4" mixing valve with 3/4" hot and cold water feeds... but I figure you know that.. ;)

1/2" pipe size will work... but it will NOT deliver the volume that the 3/4" pipes would... so expect the body sprays to be less than spectacular!

Now, what size water heater or storage tank system do you have? Gas or electric? Get back to me with this info. If you have a typical 40 gallon gas water heater then the 7.5 GPM that you mentioned, when mixed with cold water will allow you to shower full bore for only about 5-7 minutes without having to adjust the temperature... and maybe 10-12 minutes before running out almost entirely... let me know more.

The water pressure itself is also high here and over time can cause issues over the long run... so you may want to consider installing a PRV (pressure reducing valve)... see picture. In my area, if you are at 80PSI, the state/town requires you to install this valve. This valve would be installed just after the water meter.

Contrary to what most people think... increased pressure will NOT help with volume of water delivered.

MARK

mygirlsdad77 · May 1, 2009, 04:20 PM

As Mark stated, would have been best off with 3/4 supplies and valve. But as he also stated, 1/2 will work just fine. The important thing to do is make a continuous loop for the body sprays, this way you will get equal pressure out of both of them, instead of one strong and one weak. I have installed 1/2 shower valves with normal shower head and four body sprays, and(piped correctly) have had no complaints. Most of these installs had a max pressure of 65 psi. Just to put your mind at ease, yes you will be OK with 1/2". Just don't expect it to blow you over when all heads are on at the same time.

doitright1st · May 4, 2009, 06:07 AM

Thanks, Mark. I am doing a remodel and I would have definitely stubbed 3/4" to the master shower if I was starting from scratch. So, I'll have to do the best with what I have.

When you said:

"1/2" pipe size will work... but it will NOT deliver the volume that the 3/4" pipes would....so expect the body sprays to be less than spectacular!"

I tested the bathroom next to the one I have torn out and these are the results. I turned on the shower, ran the sink and flushed the toilet all at the same time and you are right, the stream from the shower head when pushed upward to almost horizontal was less than desirable and I should expect this from the body washes if I was to install them. Combine that with the added fact that I have only an electric 40 gallon water heater that some carpenter got the bright idea to encase in a closet in the garage and my options are limited (larger water heater) in order to keep "the boss" happy with long hot showers. Therefore, I have come to the conclusion that body sprays are not a very viable option in this house.

So, now I am back to a regular shower head and a hand shower off to one side. Both are 2.5 gpm fixtures. Should I go with a low volume (1.2 gpm) for the regular shower and keep the hand shower at 2.5 gpm (in order to keep the massage function)?

Oh, and I do not have that high of a water pressure, its coming in at about 62 psi.

Thanks again for all the advice guys!

massplumber2008 · May 5, 2009, 09:27 AM

Hey hey...

Mygirl'sdad had good idea in terms of piping arrangement for the body sprays, but with the 40 gallon water heater confirmed... stick with the 2 shower heads as you suggested.

Go with both at the 2.5 GPM... you got to live a little! :)

Good luck!

MARK

Milo Dolezal · May 5, 2009, 09:31 AM

As correctly advised by others above, you will not have enough volume to operate multiple shower outlets. Also, body sprays have to be plumbed in loop so they have even pressure at each head.