installation &
operating instructions
Design Envelope 4322 & 4372
Tango Pumping Unit
9
1.2.3 pump piping-general
Never connect a pump to piping, unless extra care is taken to
measure and align the piping flanges well. Always start piping
from pump.
Use as few bends as possible and preferably long radius elbows.
Do not use flexible connectors on the suction or discharge of a
Vertical In-Line pump, unless the pump is rigidly mounted to a
foundation.
Ensure piping exerts no strain on pump as this could distort
the casing causing breakage or early failure due to pump
misalignment.
All connecting pipe flanges must be square to the pipework and
parallel to the pump flanges.
Suction and discharge pipes may be increased or decreased at
pump nozzle to suit pump capacity and particular conditions of
installation. Use eccentric reducers on suction connection with
flat side uppermost.
Layout the suction line with a continual rise towards the pump
without high points, thus eliminating possibility of air pockets
that may prevent the pump from operating eectively.
A strainer of three or four times the area of the suction pipe,
installed in the suction line, will prevent the entrance of foreign
materials into the pump. C/af" (5 mm) diameter perforations in
the strainer is typical.
In open systems, test suction line for air leaks before starting;
this becomes essential with long suction line or static lift.
Install, at the pump suction, a straight pipe of a length
equivalent to four or six times its diameter; this becomes
essential when handling liquids above 120°f (49°c).
Armstrong suction guides may be used in place of the straight
pipe run and in-line strainer.
Install an isolation valve in both suction and discharge lines on
flooded suction application; these valves are used primarily to
isolate the pump for inspection or repair.
Install a non-slam non-return check valve in discharge line
between pump and isolation valve to protect pump from
excessive back pressure and to prevent water running back
through the pump in case of driver failure on open systems.
Armstrong ftv triple function valve may be installed in place of
separate check and isolation valves. The ftv valve also includes
a throttling feature which must not be used to throttle with
variable speed pumps operating in variable flow systems, unless
the pump is oversized and operating beyond the published
pump curve.
1.2.4 alignment
Design Envelope units are accurately aligned at the factory prior
to being shipped and do not need re-aligning when installed.
Alignment on a Design Envelope unit may be verified by assur-
ing an equal and parallel gap between coupling halves on both
sides of the coupling.
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