I was watching one of the varieties of the Holmes On The Range shows. Mike
was literally gushing over the Pex home run manifold that had been
installed by his plumber. I gotta admit, it was pretty nice looking. Each
curved run of Pex was perfectly spaced, with a long, sweeping, graceful
layout. Multiple runs went off to the left and the right, laid out
perfectly like a pair of angel's wings. :-)
Anyway, Mike repeated multiple times, each time with more passion, that the
system was "pressure balanced", saying that that means "if you are taking a
shower upstairs and someone flushes a toilet downstairs, the pressure in
the shower won't change."
He wasn't talking about a pressure balanced shower valve or consistent
temperatures. He specifically said the "pressure will never change."
OK, so how does that work? If multiple fixtures are opened, doesn't the
pressure in the system have to drop? It seems to me that the only way for
the pressure to never change as each additional fixture is opened is to
have the system running at some specific pressure when only one fixture is
open and then have it boosted each time another fixture is opened. After
all, you can only have so much pressure in the building to begin with -
street pressure - unless you boost it with a holding tank and a pump. There
was no mention of anything like that being installed.
What am I missing?