Gorman-Rupp Pumps PA6A60-4045D 1110032 thru 1115250 - Manual (Page 9)

PA SERIES PUMPS OM−04402
PAGE B − 3 INSTALLATION
cause excessive vibration, decreased bearing life,
and increased shaft and seal wear. If hose-type
lines are used, they should have adequate support
to secure them when filled with liquid and under
pressure.
Gauges
The pump is drilled and tapped for installing dis-
charge pressure and vacuum suction gauges. It is
recommended that gauges be installed to monitor
pump performance. Seal the gauge threads with
pipe dope to ensure an airtight seal. Follow the
sealant manufacturer’s recommendations when
selecting and applying the pipe dope. The pipe
dope should be compatible with the liquid being
pumped.
SUCTION LINES
To avoid air pockets which could affect pump prim-
ing, the suction line must be as short and direct as
possible. When operation involves a suction lift, the
line must always slope upward to the pump from
the source of the liquid being pumped; if the line
slopes down to the pump at any point along the
suction run, air pockets will be created.
Fittings
Suction lines should be the same size as the pump
inlet. If reducers are used in suction lines, they
should be the eccentric type, and should be in-
stalled with the flat part of the reducers uppermost
to avoid creating air pockets. Valves are not nor-
mally used in suction lines, but if a valve is used,
install it with the stem horizontal to avoid air pock-
ets.
Strainers
Be certain to use the strainer furnished with the
pump; any spherical solids which pass through the
strainer will also pass through the pump itself.
If a strainer not furnished with the pump is installed
by the pump user, make certain that the total area
of the openings in the strainer is at least three or
four times the cross section of the suction line, and
that the openings will not permit passage of solids
larger than the solids handling capability of the
pump.
Consult the pump Specification Data Sheet or the
factory for the solids handling capabilities of your
pump.
Sealing
Since even a slight leak will affect priming, head,
and capacity, especially when operating with a
high suction lift, all connections in the suction line
should be sealed with pipe dope to ensure an air-
tight seal. Follow the sealant manufacturer’s rec-
ommendations when selecting and applying the
pipe dope. The pipe dope should be compatible
with the liquid being pumped.
Suction Lines In Sumps
If a single suction line is installed in a sump, it
should be positioned away from the wall of the
sump at a distance equal to 1 1/2 times the diame-
ter of the suction line.
If there is a liquid flow from an open pipe into the
sump, the flow should be kept away from the suc-
tion inlet because the inflow will carry air down into
the sump, and air entering the suction line will re-
duce pump efficiency.
If it is necessary to position inflow close to the suc-
tion inlet, install a baffle between the inflow and the
suction inlet at a distance 1-1/2 times the diameter
of the suction pipe. The baffle will allow entrained
air to escape from the liquid before it is drawn into
the suction inlet.
If two suction lines are installed in a single sump,
the flow paths may interact, reducing the efficiency
of one or both pumps. To avoid this, position the
suction inlets so that they are separated by a dis-
tance equal to at least 3 times the diameter of the
suction pipe.
Suction Line Positioning
The depth of submergence of the suction line is
critical to efficient pump operation. Figure B−1
shows recommended minimum submergence vs.
velocity.
Although not recommended, the vacuum assisted
priming feature allows the pump to be operated