How to make high pressure shower

[Jonnny]

I have a new construction and contractor does not know this so I'm hoping someone here can lend some help.

My wife and I want to have 2 showers in one. So we are getting 2 shower heads and 2 hand showers. Our plumbing is 3/4" but the valves we picked up are 1/2" each. There are 2 valves. The valves are Cal Faucets StyleTherm which are thermostatic and have 7.25 gpm at 45 psi. They are single function, so only the showerhead or hand shower will be on at a time. However we have 2 valves, so 2 shower heads can possibly be on at once.

My first question is, is this setup enough for both shower heads to be forceful when they are on at the same time?

My second question, is it better to change each valves to 3/4"? The 3/4" has 16 gpm at 60 psi.

My last question relates to the second one, if we put 2 3/4" valves and they are both on at the same time, is this causing ourselves the opposite effect of what we want to achieve? I say this because 2 of the 3/4" valves might be asking for much more water than can be provided by just one 3/4" line supply. In this case maybe the 1/2" is better?

 

[BMWpowere36m3]

Most shower heads are limited to 2.5 gpm, IIRC. So unless you have more than 3 (shower heads) on at once you should be fine with the 1/2" valve.

 

[Sponsor]

 

[Jonnny]

Thanks for answering. We will definitely be removing the filter on the shower heads. So what would that give each shower head, around 5 gpm? Which if I understand what you are saying correctly, would still be below the 7.25 gpm afforded by the valve. However, would 7.25 gpm or 16 gpm from the valve make any difference in the sense that there is more water "pushing" out from the 16 gpm valve and thus putting more pressure on the shower head?

 

[Valveman]

The larger the pipe and the larger the valves the more pressure you will get to the showers. However, you are still limited by the water supply. If the supply cannot maintain 60 PSI at the volume you need, a booster pump maybe in order.

Also I hope you have an instant water heater as at 16 GPM a 50 gallon heater will be out in about 6 minutes.

 

[hj]

At 16 gpm a 50 gallon hrater may be out of water in THREE minutes, depending on its thermostat setting, and the last minute or so will only be warm water. Regardless of the size of water pipe, the opening in the valve itself will determine the flow and even a 3/4" valve has only two small openings.

 

[Jonnny]

The larger the pipe and the larger the valves the more pressure you will get to the showers. However, you are still limited by the water supply. If the supply cannot maintain 60 PSI at the volume you need, a booster pump maybe in order.

Also I hope you have an instant water heater as at 16 GPM a 50 gallon heater will be out in about 6 minutes.

This site rocks! Thank you very much for all the great and helpful answers thus far. To help me clear up what you said about being able to maintain the right volume at 60 psi, what exactly is the right volume? And in this case, is a valve rated at 7.25 gpm at 45 psi be better for me than a valve rated at 16 gpm at 60 psi?

We are buying a tankless water heate, the biggest size they come in. Any recommendations on that as well?

 

[Valveman]

At 16 gpm a 50 gallon heater may be out of water in THREE minutes, depending on its thermostat setting, and the last minute or so will only be warm water.

I was figuring a 50/50 mix of hot to cold water, but either way it won’t last long.

To help me clear up what you said about being able to maintain the right volume at 60 psi, what exactly is the right volume? And in this case, is a valve rated at 7.25 gpm at 45 psi be better for me than a valve rated at 16 gpm at 60 psi?

The right volume is whatever it takes to make the showerheads work properly. Standard is a 2.5 GPM shower head, so it would only take 5 GPM to run two of those. But if you drill out the flow restrictor or use higher flow showerheads, you will need more volume. I have helped people who have 25 GPM full body multiple showerheads. You just need enough volume and pressure for the particular showerheads.

If a ½” valve is rated at 7.25 GPM at 45 PSI, it will probably put out about 12 GPM at 60 PSI. So like HJ says there is apparently very little difference in the orifice size inside a ½” and a ¾” valve. But it still looks like the larger valve will let the showerhead have more volume and therefore better pressure as well.

I would think 45 PSI is about the minimum pressure you want for a good shower. You probably need to check the incoming pressure and figure the friction losses all the way to the shower valve.

 

[FullySprinklered]

You guys should buy each other matching pressure washers for Christmas. Set up in the back yard and go crazy.