Gorman-Rupp Pumps 81 1/2P47A-E2 3P 801781 and up - Manual (Page 15)

OM-02165 80 SERIES
OPERATION PAGE C - 3
Pump Vacuum Check
Since this pump does not have a suction check
valve, the discharge line must be fitted with a check
valve if a pump vacuum reading is to be taken.
With the pump inoperative, install a vacuum gauge
in the system, using pipe dope on the threads.
Block the suction line and start the pump. At oper­
ating speed the pump should pull a vacuum of 20
inches (508 mm) or more of mercury. If it does not,
check for air leaks in the seal, gasket, or discharge
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
Never halt the flow of liquid suddenly. If the liquid
being pumped is stopped abruptly, damaging
shock waves can be transmitted to the pump and
piping system. Close all connecting valves slowly.
If the application involves a high discharge
head, gradually close the discharge
throttling valve before stopping the pump.
After stopping the pump, disconnect the incoming
power to the motor and lock it out to ensure that the
pump will remain inoperative.
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, or
if it has been pumping liquids containing a large
amount of solids, drain the pump, and flush it thor­
oughly with clean water. To prevent large solids
from clogging the drain port and preventing the
pump from completely draining, insert a rod or stiff
wire in the drain port, and agitate the liquid during
the draining process. Clean out any remaining sol­
ids by flushing with a hose.