Gorman-Rupp Pumps 03H3-GR 285579 and up - Manual (Page 17)

OM−01201 0 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 (508,0 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.
NOTE
Petroleum products are very sensitive to changes
in temperature. Warmer temperatures elevate the
product vapor pressure, resulting in low vacuum
readings. Do not mistake temperature problems for
faulty pump installation or performance.
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.
On engine driven pumps, reduce the throttle
speed slowly and allow the engine to idle briefly be-
fore stopping.
If the application involves a high discharge
head, gradually close the discharge
throttling valve before stopping the pump.
After stopping the pump, remove the engine igni-
tion key to ensure that the pump will remain inop-
erative.
Cold Weather Preservation
If the application of this pump is limited to petro-
leum products, normal freezing conditions will not
damage the pump. However, during extremely se-
vere conditions care should be exercised during
start-up, especially if the pump has been idle for
more than a few hours.
GEARBOX TEMPERATURE CHECK
The gearbox runs higher than ambient tempera-
tures because of heat generated by friction. Tem-
peratures of approximately 200
_F (93_C) are con-
sidered normal, and can operate intermittently at
250
_F (121_C).
Checking gearbox temperatures by hand is inac-
curate. Place a contact-type thermometer against
the housing and record this temperature for future
reference.
A sudden increase in gearbox temperature is a
warning that the bearings are at the point of failing.
Make certain that the bearing lubricant is of the
proper viscosity and at the correct level (see LU-
BRICATION in Section E). Bearing overheating
can also be caused by shaft misalignment and/or
excessive vibration.
When pumps are first started, the bearings may
seem to run at temperatures above normal. Con-
tinued operation should bring the temperatures
down to normal levels within 20 minutes or less.