Connections and Manifold
Each PEX manufacturer uses slightly
different types of connections. The product that I use,
Wirsbo's Aquapex, works by slipping a reinforcing collar over
cut ends and then expanding pipe openings with a special tool.
After the opening is expanded, the tool is disengaged and a
fitting can be quickly slipped in before the PEX material
naturally contracts back to its original diameter (Figure
7. Wirsbo's PEX connects to brass fittings using
a proprietary expansion tool bit (top). The cut end of
the PEX is expanded, the fitting slides into place
(bottom), and within seconds, the PEX contracts back to
its original diameter. Rings placed outside the cut end
ensure strong, leak-free connections.
A wide variety of transition pieces are available for
special connections, such as where the service entrance
connects to PEX.
Manifolds are often used to distribute the various primary
supply lines just after the point where the main entrance line
splits at the water heater. Stock manifolds are available or
installers can assemble their own using common plumbing
materials. Manifolds, however, are not required. They tend to
be common on new construction where a separate line or home run
is piped to every wet room in a house. On repipes, however, the
idea is to limit the number of runs to minimize damage to
finished surfaces. With just a few primary runs, it's usually
possible to use common tee or wye fittings where secondary
lines branch off or 90-degree elbows for getting around tight
Because PEX is vulnerable to UV light, it can't be used
outdoors. And because it lacks rigidity, it also shouldn't be
used for hose bibbs or shower risers. I use copper in these
situations. Shower risers are not usually affected by
aggressive water because they air out when they're not in use.
And the hose bibbs are relatively easy to repair if they wear
Garry Gage runs a plumbing company in Rialto, Calif.