Xylem 19 001 251 R3 Floboy VFD Pumping System - Manual (Page 14)

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A. Piping should be sized in accordance with
the architect, engineer or factory's
direction.
B. Piping should be constructed of spring
reinforced suction hose, steel or high
density poly pipe. All joints should be
fusion welded or flanged and pressure
tested to ensure a leak proof connection.
Threaded fittings should be installed with
ample Teflon pipe joint compound and
pressure tested with air using a soap
solution to check for leaks. PVC pipe with
glued or gasketed fittings should never be
used.
C. Piping should be well-supported in order
to eliminate piping strain on the inlet of the
station. Piping strain can be tested simply
by disconnecting the piping connection
closest to the station inlet after the suction
assembly is complete. If the disconnected
piping shows signs of misalignment and
requires force to reconnect, the pump is
experiencing piping strain. Correct this
condition by changing the existing
supports or by adding more supports until
the suction piping connects to the pump
inlet with no misalignment.
D. All piping reducers should be eccentric
with the flat portion of the reducer
positioned on top. Isolation valves should
not be installed in pump suction piping.
Use a minimum number of elbows
(preferably no more than two) in any
suction pipe. These elbows should be 45-
degrees, if possible. A 90-degree elbow
may be used if positioned properly. The
elbow closest to the pump inlet should
have a section of straight pipe at least six
pipe diameters long between the elbow
and the pump inlet (Example: 4" pipe
requires 4" x 6 = 24" long piece of straight
pipe between the elbow and the pump
inlet).
E. Pump stations that lift water from a lake or
pond must be installed with a foot (check)
valve at the end of the suction pipe. The
valve should never be installed above
ground and should always be equipped
with a properly sized intake screen. The
foot valve shall be constructed of
aluminum and shall contain a rubber
flapper which sets on a machined
aluminum surface to provide a tight seal.
Ample space shall be provided for the
flapper to fold back out of the liquid
stream, keeping friction loss to a
minimum.
F. The foot valve should be positioned at
least 4 pipe diameters below the lowest
possible water level and never lay on the
bottom where silt and sand could be
sucked into the pump. It should always be
mounted in a vertical position.
Note: Never mount a foot valve at an angle
other than vertical since the valve may
experience difficulty in closing securely.
Locate and protect the suction intake from algae
or other floating material with a cleanable screen
or a diversion structure.
Note: Please consult the factory if the pump is
to take its suction from a stream or river that
might experience suspended silt, sand or other
abrasive materials. Special filters or intake
structures may be necessary to protect the
pump from premature wear and failure. The
presence of any abrasive materials will void
the factory warranty.