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D04-991-2400 5/1/04
D/G-04 Troubleshooting
Cavitation
•
Inadequate fluid supply because:
— Inlet line collapsed or clogged
— Clogged line strainer
— Inlet line too small or too long
— Air leak in inlet line
— Worn or damaged inlet hose
— Suction line too long
— Too many valves and elbows in inlet line
•
Fluid too hot for inlet suction piping system.
•
Air entrained in fluid piping system.
•
Aeration and turbulence in supply tank.
•
Inlet vacuum too high (refer to “Inlet Calculations”, page 3).
Symptoms of Cavitation
• Excessive pump valve noise
• Premature failure of spring or retainer
• Volume or pressure drop
• Rough-running pump
• Premature failure of diaphragms
Drop in Volume or Pressure
A drop in volume or pressure can be caused by one or more of
the following:
•
Air leak in suction piping
•
Clogged suction line or suction strainer
•
Suction line inlet above fluid level in tank
•
Inadequate fluid supply
•
Pump not operating at proper RPM
•
Relief valve bypassing fluid
•
Worn pump valve parts
•
Foreign material in inlet or outlet valves
•
Loss of oil prime in cells because of low oil level
•
Ruptured diaphragm
•
Cavitation
•
Warped manifold from overpressurized system
•
O-rings forced out of their grooves from overpressurization
•
Air leak in suction line strainer or gasket
•
Cracked suction hose.
•
Empty supply tank
•
Excessive aeration and turbulence in supply tank
•
Cavitation
•
Abrasives in the fluid
•
Valve incompatible with corrosives in the fluid
•
Pump running too fast
•
Worn and slipping drive belt(s)
•
Worn spray nozzle(s)
Pump Runs Rough
•
Worn pump valves
•
Airlock in outlet system
•
Oil level low
•
Wrong weight of oil for cold operating temperatures (change
to lighter weight)
•
Cavitation
•
Air in suction line
•
Restriction in inlet/suction line
•
Hydraulic cells not primed after changing diaphragm
•
Foreign material in inlet or outlet valve
•
Damaged diaphragm
•
Fatigued or broken valve spring
Premature Failure of Diaphragm
•
Frozen pump
•
Puncture by a foreign object
•
Elastomer incompatible with fluid being pumped
•
Pump running too fast
•
Excess pressure
•
Cavitation
Water (or Process Fluid) in Oil
Reservoir
•
Condensation
•
Ruptured diaphragm
•
Hydraulic cell not properly primed after diaphragm
replacement
•
Frozen pump
Strong Water (or Process Fluid)
Pulsations
NOTE: Small pulsations are normal in single-acting pumps
with multiple pumping chambers.
•
Foreign object lodged in pump valve
•
Loss of prime in hydraulic cell because of low oil level
•
Air in suction line
•
Valve spring (8) broken
•
Cavitation
•
Aeration or turbulence in supply tank
