Viega ProPress - System Performance Factors; Pressure Surges and Fitting Rotation; Fitting Deflection Management

Product Information
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IM-PP 724607 1218 ProPress
2.5.7 Pressure Surges
■ Pressure surges or transients from fast-acting valves, pump surges,
and other sources that result in water hammer may cause damage to
many system components, including press 󶈵ttings.
■ When fast-acting valves and/or pumps are incorporated into a system,
the designer and installer should isolate press 󶈵ttings from sharp
pressure surges.
2.5.8 Rotating a Pressed Fitting
Once a ProPress 󶈵tting has been pressed, it can be rotated (not by hand),
but once rotated more than 󶈵ve degrees, the 󶈵tting should be repressed
to restore resistance to rotational movement.
If the 󶈵tting is re-pressed, care should be taken to align the 󶈶at sides on
the jaw with those on the 󶈵tting.
2.5.9 De󶈶ection
The pressing process can cause de󶈶ection (angular misalignment) to
occur. When pressing Viega ProPress 󶈵ttings in a system, the deformation
of the 󶈵tting is constant. This allows for a consistent leak-free joint every
time and is a result of the pressing technique.
De󶈶ection occurs in the same way for every 󶈵tting. The 󶈵tting being
pressed will move in the direction of the jaw or ring opening.
■ Since the 󶈵tting will de󶈶ect toward the opening of the jaw or ring, the
tube end will de󶈶ect in the opposite direction.
■ By counteracting the 󶈵tting movement, one can minimize the
de󶈶ection of the 󶈵tting and ultimately the tube.
■ When using strut and clamps, de󶈶ection is minimized and nearly
eliminated depending on clamp spacing.
■ ProPress 󶈵ttings should be isolated or separated by
su󶈷cient distance from pumps, fast-acting valves, and
other sources of pressure transients.
■ The maximum operating pressure in a ProPress system
is 200 psi, which applies to general operation as well as
pressure transients.
■ Good engineering practices should be used to design
the system in a way that minimizes sharp pressure
surges.