Gorman-Rupp Pumps 13D-GX270 1421807 and up - Manual (Page 12)

10 SERIES OM−06214
PAGE B − 5 INSTALLATION
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.