Gorman-Rupp Pumps 13C2-B 715157 and up - Manual (Page 12)

10 SERIES OM-00638
PAGE B - 5 INSTALLATION
DISCHARGE LINES
Siphoning
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 causing damage to the pump
could result.
Valves
If a throttling valve is desired in the discharge line,
use a valve as large as the largest pipe to minimize
friction losses. Never install a throttling valve in a
suction line.
With high discharge heads, it is recommended that
a throttling valve and a system check valve be in­
stalled in the discharge line to protect the pump
from excessive shock pressure and reverse rota­
tion when it is stopped.
If the application involves a high discharge
head, gradually close the discharge
throttling valve before stopping the pump.
Bypass Lines
If a system check valve is used due to high dis­
charge head, it may be necessary to vent trapped
air from the top of the pump during the priming
process. This may be accomplished by installing a
bypass line from the top of the pump, back to the
source of liquid. The end of the bypass line must be
submerged. The line must be large enough to pre­
vent clogging, but not so large as to affect pump
discharge capacity.
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.
Air Release Valve Installation
The Automatic Air Release Valve must be inde­
pendently mounted in a horizontal position be­
tween the pump discharge port
and the inlet side of
the discharge check valve (see Figure 3). The inlet
opening in the Air Release Valve is equipped with
standard 1‐inch NPT pipe threads.