Gorman-Rupp Pumps PAH4C60C-B 1503565 and up - Manual (Page 15)

OM-06479 PAH SERIES
OPERATION PAGE C - 2
Overheating can occur if operated with the valves
in the suction or discharge lines closed. Operating
against closed valves could bring the liquid to a
boil, build pressure, and cause the pump to rup­
ture or explode. If overheating occurs, stop the
pump immediately and allow it to completely cool
before servicing it. Approach any over‐heated
pump cautiously.
Allow an over‐heated pump to com­
pletely cool before servicing. Do not re­
move plates, covers, gauges, or fittings
from an overheated pump. Liquid within
the pump can reach boiling tempera­
tures, and vapor pressure within the
pump can cause parts being disen­
gaged to be ejected with great force. Af­
ter the pump cools, drain the liquid from
the pump by removing the casing drain
plug. Use caution when removing the
plug to prevent injury to personnel from
hot liquid.
As a safeguard against rupture or explosion due to
heat, this pump is equipped with a pressure relief
valve which will open if vapor pressure within the
pump casing reaches a critical point. If over‐heat­
ing does occur, stop the pump immediately and al­
low it to cool before servicing it. Approach any
over‐heated pump cautiously. It is recom­
mended that the pressure relief valve assembly be
replaced at each overhaul, or any time the pump
casing over‐heats and activates the valve. Never
replace this valve with a substitute which has not
been specified or provided by the Gorman‐Rupp
Company.
Strainer Check
If a suction strainer has been shipped with the
pump or installed by the user, check the strainer
regularly, and clean it as necessary. The strainer
should also be checked if pump flow rate begins to
drop. Monitor and record the vacuum suction
gauge readings regularly to detect strainer block­
age.
Never introduce air or steam pressure into the
pump casing or piping to remove a blockage. This
could result in personal injury or damage to the
equipment. If backflushing is absolutely neces­
sary, liquid pressure must be limited to 50% of the
maximum permissible operating pressure shown
on the pump performance curve.
Pump Vacuum Check
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.
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.
Do not operate the pump against a
closed discharge throttling valve for
long periods of time. If operated against