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Unread 08-19-2018, 03:16 PM   #34
jadnashua
Veteran DIYer- Schluterville Graduate

STAR Senior Contributor

 
Join Date: Jul 2004
Location: Nashua, NH
Posts: 13,050
The biggest issue with multiple shower heads is inadequate supply. A small factor is just gravity, as simply, the pressure will drop 0.43#/foot the higher you go up. If your valve and supply line is adequately sized, balancing doesn't do much of anything. A 1/2" supply line and valve usually doesn't work well with multiple heads...at least, it often won't achieve maximum performance, but might be good enough for you. Think of the end of an open hose and how far the stream goes...now, put your thumb over it. The pressure is identical, but the spray goes further (Bernoulli principle). But, try to run multiple sprinklers or heads on an inadequate supply, and there's not enough water to create that back pressure, and the spray doesn't speed up. That's a combination of increased friction and larger openings for the water to exit. One reason a rain head has water nearly dribble out of it is that the inlet pipe opening area is small compared to the combined outlet area of the sprays nozzles...taken to a higher level...same issue with multiple showerheads/body sprays...too many openings, things slow down.

Another, functional issue, is that you can exhaust your WH quite fast when using lots of sprays...make sure you factor that into your budget, especially if there will be serial users, or simultaneous ones of the hot water supply.
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Jim DeBruycker
Not a pro, multiple Schluter Workshops (Schluterville and 2013 and 2014 at Schluter Headquarters), Mapei Training 2014, Laticrete Workshop 2014, Custom Building Products Workshop 2015, and Longtime Forum Participant.
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