Will my shower system work?

[manny_ope]

I'm plumbing a master shower remodel for quite a large shower and want to make sure I won't be biting off too much.

The master shower is on the third floor with about 40 ft of 3/4" PEX runs from the water heater and cold line. All runs will be with PEX-B and my general water pressure is always 75-85 PSI.

At the shower, I'd like the main lines branch into three circuits.

Circuit 1:
Branches off the main line with 3/4" PEX to the Kohler Anthem K-26339-NA thermostatic valve. From there, it travels via 1/2" PEX to 4 body sprays taking 1.75 GPM each connected to each other via a square loop.

Circuit 2:
Branches off the main line with 1/2" PEX to the Delta R10000-UNWSHF mixer with the 17T thermostatic cartridge and then the R11000 6 setting diverter. From there, it branches to 3 fixtures taking 1.75 GPM, 1.75 GPM, and 2.5 GPM.

Circuit 3:
Branches off the main line with 1/2" PEX to the Mr. Steam SpaH2O electronic valve. From there, it branches off to two fixtures, one taking 4.6 GPM and the other taking 2.5 GPM.

I'm a bit confused how to calculate pressure drop and whether everything would work together.

I'd never use all the fixtures at the same time, but at most, I'd use the 7 GPM body sprays from circuit 1, 2.5 GPM from circuit 2, and 2.5 GPM from circuit 3 for a total of 12 GPM.

Ideally, I'd want 1" PEX coming to the shower, but that would be quite a bit deal to redo.

I'd appreciate suggestions to my plan and some insights on whether or not my 12GPM max flow would work.

Thanks!

 

[John Gayewski]

Yes it'll work fine. You have plenty of pressure. Pex a would be slightly better as the fittings on pex b are so small. But using two shower valves is a good idea.