Gorman-Rupp Pumps T10A71S-B /FM - Manual (Page 12)

OM-05353 SUPER T SERIES
PAGE B - 5 INSTALLATION
Do not install a manual shut‐off valve in a bypass
line. If a manual shut‐off valve is installed to facili­
tate service of the Air Release Valve, the valve must
not be left closed during operation.
NOTE
The bypass line may clog occasionally, particularly
when pumping liquids containing large solids. If
clogging occurs, locate and remove the clog. If the
clog is located between the discharge check valve
and the Air Release Valve, the valve will not close. If
the clog is located in the Relief Valve itself, or in the
line between the Relief Valve and the sump, the
valve will not open.
Do not terminate the discharge line at a level lower
than that of the liquid being pumped unless a si­
phon breaker is used in the line; otherwise, a si­
phoning action could result, causing damage to
the pump.
In low discharge head applications (less than 30
feet or 9,1 meters), it is recommended that the by­
pass 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 line may be terminated with a six‐to‐
eight foot 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 or 9,1 meters), an excessive amount of liq­
uid may be bypassed and forced back to the wet
well under the full working pressure of the pump;
this will reduce overall pumping efficiency. There­
fore, 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 VALVE 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.
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 operate
without reaching prime, causing dan­
gerous overheating and possible explo­
sive rupture of the pump casing. Per­
sonnel 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 re­
moving the plug to prevent injury to per­
sonnel 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