18
• Suction hose should not have humps in it for best draft operation.
• Suction hose should be in clean area and not pull debris off the bottom of water source.
• Suction hose rubber washer must be in excellent shape to hold vacuum.
• Suction strainer should be clean and should be rated for flow of the pump.
• When priming the compound gauge should move to lower vacuum even before water is dis-
charged. If it doesn’t move during priming, stop pump and check for leaks.
• Open valves slowly and allow hose to fill. Maintain pressure with primer as required.
• Adjust throttle and discharge valves to attain desired flow and pressure.
• Set pressure control per its operating instructions (if so equipped).
• To shut down, reduce throttle and close valves (to hold prime) before disengaging pump.
For additional information, see FSG–MNL–00184, Technical Manual For Hale Single Stage Booster
Pumps. The manual is contained on the flash drive provided with the pump or on the Hale Products
website (www.haleproducts.com).
6.5. Hydrant Or Relay Operation
ALLOWING INTAKE PRESSURES TO FALL BELOW ESTABLISHED LIMITS MAY RESULT IN
DAMAGE TO THE WATER SUPPLY PIPING WHEN PUMPING FROM HYDRANT.
A hydrant or relay operation delivers water to the pump inlet with positive pressure. Operation is simi-
lar to tank operation (refer to paragraph 6.3
) with some differences noted below.
• Tank to Pump valve should remain closed when operating from positive inlet pressure.
• Primer is not typically needed. Open any discharge valve, including tank fill to evacuate air from
pump and plumbing.
• Bleed off all air from water supply hoses before opening intake valve or beginning pumping oper-
ations.
• Cavitation is possible from hydrant or relay, see Section 6.6.
6.6. Pump Cavitation
Cavitation — The sudden formation and collapse of low-pressure bubbles in the pump flow. The re-
sulting forces can be as damaging as striking the metal with a hammer. Cavitation within a pump
may sound like a hammer banging or rocks or sometimes it is described as ‘marbles’.
Cavitation can occur while pumping from draft, in relay, or from a hydrant. The operator must be
aware of the warning signs and correct the situation, or serious damage to the pump may occur.
The way to eliminate cavitation is to increase water supply to the pump, or decrease the amount of
water discharged from the pump.
See FSG–MNL–00184, Technical Manual For Hale Single Stage Booster Pumps, for more infor-
mation and charts on how different conditions affect pump lift and cavitation.
6.6.1 Discharge Pressure Cavitation Warning Signs
In a properly functioning pump, an increase in RPM will increase the discharge pressure and volume.
If an increase in engine RPM that does not cause an increase in the pump discharge pressure, the
pump is most likely in cavitation. Gauge needle bounce is a common sign of cavitation.
6.6.2 Vacuum Compound Gauge Warning Signs
The operator should not depend entirely on the vacuum (compound) gauge to indicate when a pump
is nearing cavitation. The vacuum gauge does not take into account ambient temperature or atmos-
pheric pressure and is not always accurate near zero on the scale.
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