18
H5-991-406A
H/G-25-SD 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.4).
Symptoms of Cavitation
•.. Excessive.pump.valve.noise
•.. Premature.failure.of.spring.or.retainer.(14,16)
•.. Volume.or.pressure.drop
•.. Rough-running.pump
•.. Premature.failure.of.diaphragms.()
•.. Piston.return.spring.failure.(inside.hydraulic.end)
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 - r i n g s . f o r c e d . o u t . o f . t h e i r . g r o o v e s . f r o m.
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)
•. Cracked.cylinder.casting
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.(14)
•.. Broken.piston.return.spring.(inside.hydraulic.end)
Premature Failure of Diaphragm
•. Frozen.pump
•. Puncture.by.a.foreign.object
•. Elastomer.incompatible.with.fluid.being.pumped
•. Pump.running.too.fast
•. Excess.pressure
•. Cavitation
•.. Broken.piston.return.spring.(50)
Water (or Process Fluid) in Oil
Reservoir
•. Condensation
•. Ruptured.diaphragm
•. Hydraulic. cell. not. properly. primed. after. diaphragm..
replacement
•. Frozen.pump
•. Diaphragm.screw.O-ring.(0).missing.or.cracked
•. Cracked.cylinder.casting
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.(14).broken
•. Cavitation
•. Aeration.or.turbulence.in.supply.tank
