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TM 10-4320-307-10
CAUTION
Impeller cavitation occurs when engine speed is increased beyond the point of maximum
suction vacuum. Cavitation is harmful to the pump unit and should be avoided at all times.
Cavitation is indicated by a very loud cracking noise in the pump housing.
NOTE
Engine speed and pump discharge will vary in accordance with the output demand. When
there is no increase in vacuum (suction) as indicated on the suction gauge, maximum pumping
capacity has been reached.
In case of automatic shutdown due to low suction pressure turn off POWER ON/OFF switch,
close discharge valve and recheck priming procedures.
In case of automatic shutdown due to overspeed, close discharge valve, turn off POWER
ON/OFF switch and follow starting procedures.
j.
Operational Checks.
CAUTION
Pump overheating can occur if valves in the discharge lines are closed, or if lines are otherwise
blocked while pump is operating. Operating against blocked discharge lines can bring fluid in
the pump to a boil, build pressure, and cause pump to rupture or explode. If overheating
occurs, stop pump and allow to cool before servicing.
(1) Check for engine overheating by monitoring control panel gauges for proper readings. See Table 2-3
Table 2-3. Gauge Readings/Normal Operation
Gauge
Normal Operating Range
ENGINE RPM
700 to 2100 rpm
ENGINE TEMPERATURE
(160 to 2000F) or (71 to 93°C)
ENGINE OIL PRESSURE
- At Rated RPM
(40 to 70 psi) or (276 to 483 KPa)
- At Min. RPM
(8 psi or 55 KPa)
BATTERY CHARGE
Within yellow and/or green band
SUCTION PRESSURE
(50 to 300 psig) or (345 to 2,069 KPa)
DISCHARGE PRESSURE
100 to 750 psig or (690 to 5,171 KPa)
(2)
Check entire pumping assembly for leaks. Stop operation in case of a Category Class III leak;
make necessary correction and report it to proper authority. If leaks are found that do not seriously
affect operation of the pumping assembly and if continued operation will not cause damage to
pump or engine, make note of the deficiency and see that it is corrected as soon as possible.
Examine suction and discharge piping assemblies, and check valve connections for leaks.
2-65
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