Gorman-Rupp Pumps VGH1 1/2C31-B All serial numbers - Manual (Page 14)

VGH SERIES OM--05146
OPERATION PAGE C -- 3
shown on the pump curve. (See the Parts
List Manual accompanying the pump.)
Leakage
No leakage should be visible at pump mating sur-
faces, or at pump connections or fittings. Keep all
line connections and fittings tight to maintain maxi-
mum pump efficiency.
Liquid Temperature And Overheating
Refer to the Specification Data sheet for the maxi-
mum liquid temperature for your specific pump.
Do not apply the pump at a higher operating tem-
perature.
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 and allow it to cool before servicing it. Refill
the pump casing with cool liquid.
Allow an over-heated pump to com-
pletely cool before servicing . Do not re-
move plates, covers, gauges, or fittings
from an over-heated pump. Liquid with-
in 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.
If overheating does occur, stop the pump immedi-
ately and allow it to cool before servicing it.
Ap-
proach any overheated pump cautiously.
As a safeguard against rupture or explosion due to
heat, some pumps are equipped with a pressure
relief valve which will open if vapor pressure within
the pump casing reaches a critical point. It is rec-
ommended that the pressure relief valve assembly
be replaced at each overhaul, or any time the
pump casing overheats 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. If a vacuum suction gauge has been in-
stalled, monitor and record the readings regularly
to detect strainer blockage.
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 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.
Operational Checks
Check the pump for proper operation when it is first
started and periodically thereafter to identify minor
problems.
Check the pump for unusual noises or excessive
vibration while it is operating. If noise or vibration is
excessive, stop the pump and refer to
Trouble-
shooting in the Maintenance And Repair Manual
for possible causes.