Gorman-Rupp Pumps 81 1/2D3-X.75 3P 246091 and up - Manual (Page 15)

80 SERIES OM−00758
OPERATION PAGE C − 3
Block the suction line and start the pump. At oper-
ating speed the pump should pull a vacuum of 20
inches (508,0 mm) or more of mercury. If it does
not, check for air leaks in the seal, gasket, or dis-
charge valve.
Open the suction line, and read the vacuum gauge
with the pump primed and at operation speed.
Shut off the pump. The vacuum gauge reading will
immediately drop proportionate to static suction
lift, and should then stabilize. If the vacuum reading
falls off rapidly after stabilization, an air leak exists.
Before checking for the source of the leak, check
the point of installation of the vacuum gauge.
STOPPING
After stopping the pump, disconnect the incoming
power to the motor and lock it out to ensure that the
pump will remain inoperative.
Do not operate the pump against a
closed discharge throttling valve for
long periods of time. If operated against
a closed discharge throttling valve,
pump components will deteriorate, and
the liquid could come to a boil, build
pressure, and cause the pump casing to
rupture or explode.
Cold Weather Preservation
In below freezing conditions, drain the pump to
prevent damage from freezing. Also, clean out any
solids by flushing with a hose. Operate the pump
for approximately one minute; this will remove any
remaining liquid that could freeze the pump rotat-
ing parts. If the pump will be idle for more than a
few hours, drain the pump, and flush it thoroughly
with clean liquid. Operate the pump during the
draining process.