Need Advice: Pressure Balancing Loop vs...

[JMCameron]

Hello. We are doing a shower remodel and the plumbing for the shower was finished yesterday. I have read on this forum that pressure balancing loops aren’t always necessary, specifically if the sprayers are close together. My question is what you guys think of how these Delta body sprayers were done? Will they have similar pressure or do I need to change it?

 

[hj]

It is how I always do it.

 

[Sponsor]

 

[JMCameron]

It is how I always do it.

Thank you! I had read another post of yours where you recommended a T shape. I didn’t know if the asymmetry of this T would cause any issues?

 

[Themp]

I am not a plumber, but noticed that there are hot and cold supply shutoffs below the shower valves and heads. Are these going to be made accessible after the tile is complete? Maybe these are used for testing prior to tile. But it might be nice to have access to these shutoffs from the back side of the shower.

 

[JMCameron]

I am not a plumber, but noticed that there are hot and cold supply shutoffs below the shower valves and heads. Are these going to be made accessible after the tile is complete? Maybe these are used for testing prior to tile. But it might be nice to have access to these shutoffs from the back side of the shower.

They won’t be accessible without removing some drywall, but they will help with testing.

 

[Plumber69]

Your rough in has shut off's built in to the body. The valves below are pointless. I would of ran hot and cold copper to the first valve and definitely up to the mixing valve. I probably would of ran copper to the 3 body sprays to

 

[Jadnashua]

The key is to add up all of the rated gpm of everything that may be on at the same time, then, look at the valve's capacity and relate that to the piping size and type used. 1/2" pex is rated at a max of about 5gpm before friction starts to reduce the available volume. Most 1/2" shower valves are also rated at 5-6gpm. If you can supply more volume than the devices are designed for, you should not see a volume issue. I think with the body sprays and a shower head, you'll be maxing out or trying to exceed the capacity of the piping and valve. Think of it like a soaker hose...too many outlets for them to increase the velocity of the water verses trying to put that same volume out a single spray nozzle. To get good spray, there must be more water than the units can deliver, which then causes the water to accelerate going through the nozzle (Bernoulli effect). Otherwise, it just dribbles out (worst case).

Volume and pressure are related, but not the same thing. You are likely near or above the volume you can supply, which can compromise performance.

 

[JMCameron]

The key is to add up all of the rated gpm of everything that may be on at the same time, then, look at the valve's capacity and relate that to the piping size and type used. 1/2" pex is rated at a max of about 5gpm before friction starts to reduce the available volume. Most 1/2" shower valves are also rated at 5-6gpm. If you can supply more volume than the devices are designed for, you should not see a volume issue. I think with the body sprays and a shower head, you'll be maxing out or trying to exceed the capacity of the piping and valve. Think of it like a soaker hose...too many outlets for them to increase the velocity of the water verses trying to put that same volume out a single spray nozzle. To get good spray, there must be more water than the units can deliver, which then causes the water to accelerate going through the nozzle (Bernoulli effect). Otherwise, it just dribbles out (worst case).

Volume and pressure are related, but not the same thing. You are likely near or above the volume you can supply, which can compromise performance.

The body sprayers are rated at 2 GPM each, the shower head at 2.5 GPM and the shower wand at 2.5 GPM. The diverter valve only allows for a max of 2 “systems” to be on together at a time. How would this need to be plumbed if the sprayers and shower head together need 8.5 GPM? Is PEX not an option?

https://s2.img-b.com/build.com/medi...973746/delta-dss-vero-17t03-specsheet-184.pdf

 

[Jadnashua]

While you'll get water out of each, your valve with 1/2" pex (or copper!) supplies will not give you the results you really want IMHO. Whether it will be acceptable to you, can't say. You can exceed the maximum recommendations by the respective pipe manufacturers (on 1/2" copper, the hot should be limited to 4gpm...pex allows it to go faster - 8fps versus 5fps for copper), and the pipe can support a bit more than the recommendations, it comes with consequences:
- flow noises increase
- friction and thus dynamic pressure drops
- especially on copper, you can literally start to erode the pipe from the inside out, especially near fittings or improperly done joints that create turbulence - it can erode fittings on pex as well.

Those recommendations by the Pex and Copper industries are there for a reason - if followed, you won't be disappointed. FWIW, because of the increased opening of a 3/4" pipe, it doubles the flow over a 1/2" line.

I can't say whether you'll be happy with it, but it won't perform as well as it could if your pipes (all the way back to the supply) were larger, and you had a larger valve body. With 1/2" pex feeding the three body sprays, they want 6gpm based on what you said, and the industry says the pipe shouldn't be used for more than 4. Something has to give. It will be sort of like the outlet of a hose with and without a nozzle on the end...it needs a restriction in what's available to accelerate the flow....think thumb over the end of a hose...same volume, but the spray goes further. Too many outlets, there's not enough volume to keep up max capacity.

A secondary part to all of this is that it can take a massive hot water tank to run it at full blast for very long. A drain water heat recovery system can help minimize that load if you have the vertical drop available and are willing and able to replumb things to accommodate one.

 

[JMCameron]

While you'll get water out of each, your valve with 1/2" pex (or copper!) supplies will not give you the results you really want IMHO. Whether it will be acceptable to you, can't say. You can exceed the maximum recommendations by the respective pipe manufacturers (on 1/2" copper, the hot should be limited to 4gpm...pex allows it to go faster - 8fps versus 5fps for copper), and the pipe can support a bit more than the recommendations, it comes with consequences:
- flow noises increase
- friction and thus dynamic pressure drops
- especially on copper, you can literally start to erode the pipe from the inside out, especially near fittings or improperly done joints that create turbulence - it can erode fittings on pex as well.

Those recommendations by the Pex and Copper industries are there for a reason - if followed, you won't be disappointed. FWIW, because of the increased opening of a 3/4" pipe, it doubles the flow over a 1/2" line.

I can't say whether you'll be happy with it, but it won't perform as well as it could if your pipes (all the way back to the supply) were larger, and you had a larger valve body. With 1/2" pex feeding the three body sprays, they want 6gpm based on what you said, and the industry says the pipe shouldn't be used for more than 4. Something has to give. It will be sort of like the outlet of a hose with and without a nozzle on the end...it needs a restriction in what's available to accelerate the flow....think thumb over the end of a hose...same volume, but the spray goes further. Too many outlets, there's not enough volume to keep up max capacity.

A secondary part to all of this is that it can take a massive hot water tank to run it at full blast for very long. A drain water heat recovery system can help minimize that load if you have the vertical drop available and are willing and able to replumb things to accommodate one.

Thank you, this is very informative. It’s odd to me that Delta sells the valve body that won’t supply the components designed to work with it. Slightly frustrating. I read through the paperwork and I only saw 1/2” mentioned throughout.

 

[Jadnashua]

There are body sprays that are designed for lower volume...someone mentioned some that were rated 0.9gpm, less than half of what you have. The federal guidelines have maximum flow restrictions (2.5gpm), but not minimum flow ones. The design matters, too, in the perceived output. WHether your rough-in will have the proper setback to allow you to experiment after the tile is up, can't say, you'd have to study the spec sheets and installation manuals carefully. That may be an option that would help. Things aren't always all that clear, and experimentation may be called for. But, given the dynamics of the tubing suppliers, I'd question whether it will be as designed. Whether it's good enough for you, you won't know until you try. Lower flow body sprays should help a lot, but this is from theory. What happens in practice may differ some as will expectations.

 

[Homeworks Designs]

All manufacturers recommend creating a pressure loop when installing body sprays in your shower system, regardless of spray type. The pressure loop ensures consistent pressure and temperature from all the body sprays. This is a highly desirable feature in shower systems that include multiple spray outlets. A pressure loop is a small additional cost for extra fittings, and will give you the best results in water pressure for your sprays. Once the wall is closed, it is not something you can easily change if you do not create a pressure loop when installing. I found this great blog post that highlights shower system installation with multiple spray outlets. Here you will also find more information about creating a pressure loop.

https://faucetlist.com/blogs/buying...and-shower-installation#bodyspraypressureloop

 

[Plumber69]

I would of ran all copper to, but no loop. Loop if there was 4 but not 3