Plumbing Body Jets, Moen vertical spa

[katiebear00]

I purchased a Moen vertical spa system that includes 4 body jets, and the instructions call for all 4 jets to go on the front wall with the control valve. See the picture below for the layout. I'd like to deviate from this configuration, and put two of the jets on the back wall directly opposite the control valve and shower head. If I maintain a pressure balancing loop, does it matter of two of the valves are further away than the other two? Also, can I add a second shower head if I add another pressure balancing loop?

 

[hj]

shower

In the first place a balancing loop is more cosmetic than practical. If you look at your drawing, all the loop does is make sure there is adequate water, and a larger pipe would do that, assuming it was really necessary.

 

[Sponsor]

 

[katiebear00]

That makes sense, but my shower valve has 1/2" fittings. If I used adapters to get up to 3/4" pipe, would that work? If so, could I ditch the loops?

 

[Jadnashua]

If those body sprays are 2.5 gpm, you might not be happy with the 1/2" supply. that exceeds the preferred flow rate of 1/2" pipes from what I remember. The manufacturers usually indicate the max flow rate for their valves burried in the specs. With the 1/2" version of yours, what does it say? Also keep in mind you will be drawing down on your hot water supply pretty quickly, so I hope you've planned for that as well.

 

[katiebear00]

If those body sprays are 2.5 gpm, you might not be happy with the 1/2" supply. that exceeds the preferred flow rate of 1/2" pipes from what I remember. The manufacturers usually indicate the max flow rate for their valves burried in the specs. With the 1/2" version of yours, what does it say? Also keep in mind you will be drawing down on your hot water supply pretty quickly, so I hope you've planned for that as well.

The body sprays are indeed 2.5gpm, but the spec sheet for the valve here doesn't list a max flow rate, and I couldn't find one anywhere else. Since this vertical spa system is sold as a set, shouldn't it all be compatible? I'm replacing my existing 50 gal hot water heater with an 80 gal.

 

[katiebear00]

I called Moen, and they told me the capacity of the valve is 7gpm at 60psi, but the system should work fine as long as my pressure is at least 45gpm. I guess the only way to know for sure is to install it the way I want it, and test the flow out of each head before I close up the walls. I'll start removing body jets one by one if the flow is too weak.

 

[Jadnashua]

Humm, say you get 7gpm and the body sprays are rated at 2.5gmp each...you will NOT be getting the designed pressure out of them, it will still come out, but not anywhere nearly as forceful as they were designed for.

 

[Geniescience]

i'm not clear if you are asking whether to skip making a loop, or whether to remove a jet or two.

imho, since you have 1/2" pipe in this house, you need the loop. Even if you increase pipe size to 3/4" for a few feet before the jets. Better still, make the loop out of 3/4" pipe too!

i don't think you'll need to remove jets.

david

 

[katiebear00]

Sorry I wasn't clear. My original question was if I put two of the 4 jets on the wall opposite the valve, will the extra pipe length and 90 degree turns reduce the flow much more than to two jets on the same wall as the valve.

Now I'm puzzled why Moen would sell a shower kit that includes a 7gpm valve, and 6 fixtures each rated at 2.5gpm.

Finally, I'd like to know if it's worth it to run a few feet of 3/4" pipe to reach the jets, when both the jets and valve have 1/2" fittings. Wouldn't the 1/2" fittings effective reduce the flow to the same rate as using 1/2" pipe?

 

[Geniescience]

AFAIK it is far better to use 3/4" pipe for any length that you can, for a few reasons, including friction losses you already mentioned, friction losses in elbows and in distance. Just to reduce that to the minimum, and then to ensure dynamic pressure and flow are equalized. A big pipe is good for all reasons.

the fact that the water then has to go through a 1/2" space to get through the shower nozzle and out into the shower, is not a big concern. Sooner or later it has to squeeze through a little opening, to be a shower jet. i wouldn't worry more; i would just install it. A million other people have installed this or similar setups, and lived to tell the tale without complaining.

david