OM-06845
SUPER T SERIES
PAGE B - 8
INSTALLATION
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 (9,1 m)), it is recommended that the bypass
line be run back to the wet well, and located 6
inches 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
(1,8 to 2,4 m) length 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 (9,1 m), 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 re
duce overall pumping efficiency.
Therefore, it is
recommended that a Gorman‐Rupp Automatic
Air Release Valve be installed in the bypass 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.
Except in certain specific applications (to
prevent flooding during service of an auto
matic air release valve in a below‐ground
lift station), if a manual shut‐off valve is in
stalled
anywhere
in a bypass line, it
must
be a full‐opening,
ball‐type
valve to pre
vent plugging by solids.
A manual shut‐off valve should not be installed
in any bypass line. A manual shut‐off valve may
inadvertently be left closed during operation. A
pump which has lost prime may continue to op
erate without reaching prime, causing danger
ous overheating and possible explosive rupture
of the pump casing. Personnel could be severe
ly injured.
Allow an over‐heated pump to completely cool
before servicing. Do not remove plates, covers,
gauges, or fittings from an over‐heated pump.
Liquid within the pump can reach boiling tem
peratures, and vapor pressure within the pump
can cause parts being disengaged to be ejected
with great force. After the pump completely
cools, drain the liquid from the pump by remov
ing the casing drain plug. Use caution when re
moving 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.
