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Pump Troubleshooting Guide Chart

Pump Troubleshooting:

The pump is a mechanical device which is commonly used for different industrial purposes with continuous operation. At pump startup or during operation of the pump, many troubles founds which are disturbing pump normal operation. Here are the common pump troubleshooting and faults of the centrifugal pumps, Reciprocating pumps, and rotary pumps.

1. Centrifugal Pump Troubleshooting and faults:

Following are the Centrifugal Pumps troubles and faults:

If the pump runs without flow, then following faults may be occurring

  • Speed too low
  • Pump not primed before startup
  • Wrong direction of pump impeller rotation
  • Design head is lower than system head
  • Too high suction lift
  • Air trapped in suction line/ piping

If pump running with Insufficient Flow, then faults are

  • Speed too low
  • Suction lift is too high
  • Impeller passage not clean
  • Air leakage in the suction piping
  • Small foot valve
  • Foot valve partially clogged or blocked
  • The viscosity of liquid different
  • System head higher
  • Impeller diameter less
  • Pump rotates in reverse direction

If pump running with the Excessive flow, faults are

  • Speed too high
  • Low system head
  • Wrong supply of pump
  • Impeller diameter more

If excessive head, then faults are

  • Speed too low
  • System head low

If the head is low, then faults are

  • Speed too low
  • Air trapped in the liquid
  • The viscosity of liquid different
  • Impeller damaged

If pump discharges intermittently and/or pump runs dry, faults are

  • Liquid level low or suction lose
  • Air leakage in the suction line
  • Strainer choked
  • Air leakage through the stuffing box

If pump efficiency low, then following faults exist

  • Extra internal losses due to leakage
  • More frictional resistance

If pump absorbs excessive power, faults are

  • Too tight gland
  • Excessive suction lift
  • Speed too high
  • Density and viscosity of liquid higher
  • Head low and pump delivers too much
  • Bent/ tilted shaft
  • Wearing rings damaged

If the pump runs hot:

  • Shaft out of alignment or bent
  • Imbalanced Impeller
  • Worn out bearing
  • Lack or absence of proper lubrication

If pump vibrates and/or is noisy:

  • Shaft misalignment
  • Impeller not balanced
  • Pump running at critical speed
  • Available NPSH insufficient
  • Cavitation occurring
  • Foundation bolts loose

2. Reciprocating pump Troubleshooting and faults:

Following are the reciprocating pump troubles and faults:

If noise at the liquid end, faults are

  • Inadequate suction pressure
  • Partial priming
  • Air trapped in the liquid
  • Speed too high
  • Poor supporting of suction or discharge pipe
  • Valve opening blocked or improper valve function
  • System shocks

If noise power/ motor end, faults are

  • Bearing loose or worn out
  • Plunger loose
  • Oil level low

If overheated power/ motor end side, then faults are

  • High pressure or high speed
  • Misalignment
  • Too tight Belts
  • Bearings tight
  • Oil level low

If Plunger/ Packing wear:

  • Contaminated/ dirty liquid
  • Wrong Pump alignment
  • Loose Packing

If Valve pitting occurs, the following are the causes

  • Corrosion
  • Cavitation
  • Solids in liquid (erosion)

If oil leakage from the crankcase, faults are

  • Oil level too high
  • Seals wore/ damaged

3. Rotary pump Troubleshooting and faults:

Following are the Rotary pumps troubles and faults:

If a pump fails to discharge, faults are

  • Priming not full/ Improper priming
  • Suction pipe not submerged/ underwater
  • Strainer choked
  • Leakage in Foot valve
  • Suction lift too high
  • Air leakage in the suction piping
  • Low speed
  • Wrong direction of rotation

If pump discharge less, then following faults occur

  • Strainer clogged
  • Suction lift too high
  • Air leakage in the suction piping
  • Speed low
  • Air leaking in packing

If pump absorbs excessive power, common faults are

  • The viscosity of liquid higher
  • Shaft bent
  • Packing too tight
  • Discharge line/ valve choked

If the pump is noisy, then causes or faults are

  • Excessive pressure
  • Shaft bent
  • Air leakage in suction pipe/ line
  • Shaft misalignment
  • Loose foundation bolts

If the pump starts, then lose suction, faults are

  • Pump not primed properly
  • Suction pipe not submerged
  • Air leakage in suction piping/ line

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