Graham Corporation
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2.9 Piping Requirements
A) Suction and Discharge Piping
The suction and discharge flanges on the pump are arranged vertically and are marked with
arrows on the pump casing. The suction and discharge piping should be the same nominal size as
the pump flanges. The elevation of the discharge separator above the discharge flange should be
limited to an elbow turning horizontally.
If necessary, a discharge leg can be used with a maximum of 24 inches (610 mm) above the
pump discharge flange. Too high an elevation in this line will cause excessive backpressure on
the pump, overload the motor, and reduce the pump capacity.
Remove the protective coverings from the pump openings just before attaching the piping.
Check that all foreign matter such as weld slag, nuts, bolts, rags, and dirt has been cleaned out of
the piping before connecting to the pump. The piping flanges must fit easily and without strain
on the pump flanges and the flange bolt holes must be in alignment. The flange gaskets must not
protrude into the bore of the piping or pump flanges. All piping must be supported
independently on each side of the pump without transmitting any strain to the pump casing. A
temporary suction strainer fitted at the suction inlet is recommended during the first 100 hours
of operation.
B) Service Liquid Piping
In a once-through arrangement, the nominal pipe size should be the same size as the service
liquid connection. In a total recirculation package with no recirculation pump, use one nominal
pipe size larger than the service liquid connection of the pump. Also, use the least number of
fittings to minimize the pressure drop. When a recirculation pump is used, the piping should be
the same size as the service liquid connection.
2.10 Electrical Requirements
All electrical wiring and installation must comply with local safety codes.
After the electrical work is complete, the motor should be jogged to check for proper rotation.
First, turn the pump by hand to see that it rotates freely. On Series 1 pumps, it may be
necessary to loosen the gland packing rings (see Section 3.2) to allow the shaft to turn easily.
The direction of rotation is marked on the pump. Second, jog the motor momentarily to check
the rotation. It is recommended to use a non-reversing motor controller to prevent the pump
from turning in the wrong direction.
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