Reciprocating Pumps Trouble Shooting Guide

Issuing time:2020-11-27 13:50
Top Low Volumetric Efficiency (Failure To Deliver Rated Capacity And Pressure)
  1. Air or vapor pocket in inlet line

  2. Capacity of charge pump less than capacity of power pump

  3. Air or vapor trapped in or above inlet manifold

  4. Air leak in liquid supply piping system

  5. Loose bolts in pump inlet manifold

  6. Air or gases entrained in liquid

  7. Foreign object holding pump inlet or discharge valve(s) open

  8. Incorrect drive ratio

  9. Loose belts

  10. Incorrect motor or engine speed

  11. Loose valve covers or cylinder head

  12. Worn valves and seats

  13. Safety relief valve partially open, or not holding pressure

  14. Worn liners, piston rings or plungers

  15. Bypass valve open, or not holding pressure

  16. Blown liner gasket

  17. NPSHA not sufficient

  18. Liquid bypassing internally

  19. Foreign object blocking liquid passage

  20. Vortex in supply tank

  21. Insufficient power delivered by motor

Top NPSHA Too Low
  1. Inlet line partially clogged

  2. Liquid vapor pressure too high

  3. Liquid pumping temperature too high

  4. Restricted inlet pipe fittings

  5. Inlet line too long

  6. Too many pipe fittings

  7. Too small inlet line

  8. Too low static inlet head

  9. Too low atmospheric pressure

Top Liquid Not Delivered
  1. Pump not primed

  2. Air or vapor pocket in inlet line

  3. Clogged inlet line

  4. All inlet valves propped open

  5. All discharge valves propped open

  6. Loose bolts in pump inlet manifold

  7. Too high valve velocities

Top Cavitation
  1. NPSHA too low

  2. Liquid NOT Delivered to Pump Inlet Connection

  3. Excessive Stuffing Box Leakage

  4. NPSHR too high

Top Leak at Cylinder Head or Valve Cover
  1. Over Recommended Pressure

  2. Loose Cylinder Head/Valve Cover

  3. Damaged Gasket/O-ring

Top Water in Crankcase/Oil
  1. Water Condensation

  2. Worn seals

  3. Clogged Air Breather(s)

  4. Worn Crankcase Packing

  5. Loose Covers

Top Oil Leakage from Crankcase
  1. Oil Level/Temperature Too High

  2. Worn seals

  3. Worn Crankcase Packing

  4. Loose Crankcase Cover

Top Excessive Heat in Power End
  1. Pump Running Backward/RPM too low 2) Insufficient Oil in Power End

  2. Excessive Oil in Power End

  3. Incorrect Oil Viscosity

  4. Operating Pump above Recommended Pressure 6) Main Bearings too Tight

  5. Drive Misaligned

  6. Belts too Tight

  7. Discharge Valve, one or more, Stuck Open 10) Insufficient Cooling

  8. Pump RPM too Low

  9. Inadequate Ventilation

  10. Liquid End Packing Adjusted too Tight (adjustable style packing only)

Top Pump Overloads Driver
  1. Pump RPM too High

  2. Low Voltage or other Electrical Trouble

  3. Trouble with Engine, Turbine, Gear Reducer or other Related Equipment

  4. Excessive Discharge Line Pressure

  5. Clogged Discharge Line

  6. Closed/Throttled Valve in Discharge Line

  7. Incorrect Plunger/Piston Size for Application

  8. Improper Bypass Conditions

  9. Over-tightened Stuffing Box Glands on Adjustable Packing

Top Stuffing Box Leakage
  1. Worn Packing

  2. Worn rods or plunger

  3. Worn stuffing boxes

  4. Wrong size packing

  5. Worn O-ring seal (replaceable boxes)

Top Stud Failure
  1. Excessive discharge pressure

  2. Improper torquing of nuts

  3. Shock overload caused by pump cavitation

Top Excessive Valve Noise
  1. Broken or weak valve spring

  2. Pump cavitation

  3. Air leak in inlet piping or loose bolts in pump inlet manifold

  4. Air trapped above inlet valve

Top Inlet or Discharge Line Vibration
  1. Piping inadequately supported

  2. Inlet line too long or too small in diameter

  3. Too many bends in inlet line

  4. Multiple pump installations operating in phase

  5. Obstruction Under Valve(s)

  6. Packing Worn

  7. Operating Above Recommended Pressure or RPM 8) Low NPSHA

Top Noisy Operation (Be sure to differentiate between liquid knock and mechanical knock - very few knocks are mechanical on new installations.)
  1. Piston or plunger loose

  2. Valve noise amplified through power end

  3. Pump cavitation

  4. Liquid knock

  5. Air leak in inlet piping

  6. Loose bolts in pump inlet manifold

  7. Hydraulic noise in liquid end

  8. Loose or worn crosshead pins and bushings

  9. Loose connecting rod cap bolt

  10. Worn connecting rod bearings

  11. Worn crosshead

  12. Main bearing end play excessive

  13. Worn gears or chains

  14. Gears or chains out of line

  15. Pump running backward

  16. Partial loss of prime

  17. Shocks in piping system

  18. Water in power end crankcase

  19. Poorly supported piping, abrupt turns in piping, piping misaligned, pipe size too small



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