Centrifugal Pump Troubleshooting | Great Lakes Pump

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Centrifugal Pump Troubleshooting

Centrifugal Pump Troubleshooting

Condition Possible cause(s)
No fluid is delivered
  • Pump is not primed
  • Speed is too low
  • Required discharge head is too high compared to pump design
  • Suction line or strainer is clogged
  • Impeller is completely clogged 
  • Wrong pump rotation direction / motor wired wrong
  • Too much clearance between impeller and intake flange
Not enough fluid is delivered
  • Air leaks in suction or stuffing boxes
  • Speed is too low
  • Required discharge head is greater than anticipated
  • Too much clearance between impeller and intake flange
  • Impeller is partially clogged
  • Mechanical defects such as a worn impeller wear ring or damaged impeller.
  • Impeller diameter is too small
  • Foot valve at end of suction line is too small, allowing fluid to exit and compromising prime.
  • Foot valve or suction opening are not submerged deep enough. NPSHr > NPSHa
Not enough pressure
  • Speed too low
  • Air entrained in the fluid
  • Mechanical defects such as worn impeller ring or damaged impeller
  • Impeller diameter too small
  • Pump producing too much flow, insufficient back-pressure
Vibration / Noise
  • Bent shaft
  • Pipe strain
  • Impeller clogged, causing imbalance
  • Motor – pump coupling misalignment
  • Pump is not fully secured to its mounting base
  • Motor and/or pump bearings are going bad
  • Pump is cavitating – insufficient fluid level
Pump takes too much power
  • Speed is too high
  • Actual head is lower than its rating, pumping too much fluid
  • Specific gravity or viscosity of fluid is too high and/or weren’t taken into account when the pump and motor were sized.
  • Mechanical defects such as bent shaft, power frame in a bind, worn impeller wear ring.
Stuffing box is leaking – mechanical seal failure
  • Over time, this is normal. Mechanical seals will fail eventually. They are more prone to failure when incorrect seal faces are used given the composition of the fluid pumped, when seals are not properly flushed, when the pump runs dry,
Bearings are running hot
  • Improper lubrication – use of incompatible lubricant, too infrequent lubrication, or over-lubrication
  • Lube cooling (outside service?)
  • Improper pump and motor alignment
Pump starts to pump then ceases
  • Improper pump priming
  • Air leak in suction line
  • Air or vapor pocket accumulation

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Great Lakes Pump & Supply Co.
1075 Naughton
Troy, MI 48083
Phone: 248-528-9100

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