Gorman-Rupp Pumps 16D60-F3L 1318307 and up - Manual (Page 13)

OM-05534 10 SERIES
PAGE B - 6 INSTALLATION
NOTE
The bypass line should be sized so that it does not
affect pump discharge capacity; however, the by­
pass line should be at least 1 inch (25,4 mm) in di­
ameter to minimize the chance of plugging.
In low discharge head applications (less than 30
feet (9 meters), it is recommended that the bypass
line be run back to the wet well, and located 6
inches (152,4 mm) below the water level or cut‐off
point of the low level pump. In some installations,
this bypass outline may be terminated with a six‐to‐
eight foot length (1,8 to 2,4 m) of 1‐1/4 inch (31,8
mm) I.D. smooth‐bore hose; air and liquid vented
during the priming process will then agitate the
hose and break up any solids, grease, or other
substances likely to cause clogging.
A bypass line that is returned to a wet well
must be secured against being drawn into
the pump suction inlet.
It is also recommended that pipe unions be in­
stalled at each 90
_ elbow in a bypass line to ease
disassembly and maintenance.
In high discharge head applications (more than
30 feet or 9 meters), an excessive amount of liquid
may be bypassed and forced back to the wet well
under the full working pressure of the pump; this
will reduce overall pumping efficiency. Therefore,
it is recommended that a Gorman‐Rupp Auto­
matic Air Release Valve be installed in the by­
pass line.
Gorman‐Rupp Automatic Air Release Valves are
reliable, and require minimum maintenance. See
Automatic Air Release Valves in this section for
installation and theory of operation of the Auto­
matic Air Release Valve. Consult your Gorman‐
Rupp distributor, or contact the Gorman‐Rupp
Company for selection of an Automatic Air Release
Valve to fit your application.
If a manual shut‐off valve is installed in a
bypass line, it must not be left closed
during operation. A closed manual shut‐
off valve may cause a pump which has
lost prime to continue to operate with­
out reaching prime, causing dangerous
overheating and possible explosive
rupture of the pump casing. Personnel
could be severely injured.
Allow an over‐heated pump to com­
pletely cool before servicing
. Do not re­
move plates, covers, gauges, or fittings
from an over‐heated pump. Liquid with­
in the pump can reach boiling tempera­
tures, and vapor pressure within the
pump can cause parts being disen­
gaged to be ejected with great force. Af­
ter the pump completely cools, drain
the liquid from the pump by removing
the casing drain plug. Use caution when
removing the plug to prevent injury to
personnel from hot liquid.
AUTOMATIC AIR RELEASE VALVE
When properly installed, a Gorman‐Rupp Auto­
matic Air Release Valve will permit air to escape
through the bypass line and then close automati­
cally when the pump is fully primed and pumping
at full capacity.
Some leakage (1 to 5 gallons [3.8 to 19
liters] per minute) will occur when the
valve is fully closed. Be sure the bypass
line is directed back to the wet well or
tank to prevent hazardous spills.
Consult the manual accompanying the Air Release
Valve for additional information on valve installation
and performance.
ALIGNMENT
The alignment of the pump and the engine is criti­
cal for trouble‐free mechanical operation. See Sec­
tion E, Securing Intermediate And Drive Assem­
bly To Engine for detailed information.