Viking Pump TSM343.3: Vi-Corr Pumps - Manual (Page 4)

SECTION TSM 343.3 ISSUE F PAGE 4 OF 20
Piping/Hose
The cause of many pumping problems can be traced to the suction piping. It should always be
as large in diameter and as short in length as possible.
Before starting the layout and installation of your piping system, consider the following
points:
1. Never use piping smaller than the pump port connections. Piping larger in diameter than the
port connection is sometimes required to reduce friction losses.
2. Be sure the inside of the pipe is clean before installing.
3. When approaching an obstacle to the suction line, go around instead of over it. Going over
an obstacle can create an air pocket. Where practical, slope the piping so no air or liquid
pockets will be formed. Air pockets in the suction line make it hard for the pump to prime.
4. A strainer on the suction side of the pump should always be considered in any pumping
system. The strainer will keep foreign matter from entering the pump. The strainer mesh or
perforation size should be large enough so that it does not cause excessive pressure drop,
but fine enough to protect the pump. Use of a strainer is particularly important at start up to
help clean the system of weld beads, pipe scale and other foreign objects.
5. A pressure relief valve is required in the discharge line. See Special Information, page 2.
6. The pump must not be used to support the piping. Hangers, supports, stands, etc. must
carry the weight of the pipes.
7. When fastening piping to the pump do not impose any strain on the pump casing. “Springing”
or “drawing” the piping up to the pump will cause distortion, possible misalignment and
probable rapid wear of the pump. Do not use the pump to correct errors in piping layout or
assembly.
8. All joints in the piping system must be tight; liquid thread sealant will help assure leak-free
threaded joints. Loose joints result in liquid leaks or suction side leaks. Air leaks make the
pump noisy and reduce flow. CAUTION: Be careful not to overtighten fittings as this
can cause cracked joints. One full turn beyond hand tight is all that is needed for
proper connection. Do not use PTFE / plumber’s tape. Reduced friction makes over
tightening very easy and will result in cracked ports.
9. Drive alignment must be checked after the piping is hooked up.
10.Provide a pressure relief device in any part of a pump and piping system that can be valved
off and, thus, completely isolated. A rise in temperature will cause a liquid to expand. If there
is no provision for pressure relief in the closed off section, there is a chance that the pump
or piping will rupture.