Almost all PEX plumbing is installed using the "home-run"
system, where separate hot and cold supply lines for each
fixture run back to a central manifold. Several companies
supply manifolds for these systems (see "Sources of Supply,"
page 31), but I prefer to make my own manifolds out of copper
and brass components (see Figure 1).
1. Standard manifolds are available from PEX suppliers
(left), but the author prefers to make his own from copper pipe
and brass fittings (right).
My shop-built or site-built manifolds cost less than the
store-bought brands, give me more flexibility, and are easier
to modify if the customer wants to add runs later on. And since
I make my manifolds from common materials that are readily
available, I don’t have to worry that parts won’t
be available if I need them five or ten years from now.
Each manifold has a hot and cold main, with fittings as
needed for each fixture. We pair up the hot and cold supply for
each sink or shower opposite each other, and clearly label each
line to show which fixture it serves. Some brands of PEX come
in a variety of colors so hot and cold lines can be
color-coded; alternatively, we simply mark hot and cold lines
with red and blue tape.
Each line has its own shutoff valve at the manifold, as well
as the usual shutoff valve at the fixture. The hot and cold
manifold mains also have individual shutoff valves in case we
need to make a repair or expand the system.
PEX is best cut with a special scissors-type cutter with a
sharp blade (Figure 2).
2. PEX tubing can be cut with a special
scissorslike tool (left), or simply with a sharp
pocketknife. A crisp, square cut is critical for a
With a slight rotation while you squeeze the handles, you
have a perfect square cut. Several PEX manufacturers supply
various versions of this tool.