Troubleshooting a running centrifugal pump

TROUBLESHOOTING A RUNNING CENTRIFUGAL PUMP PT002

The pump is hooked up to the piping and running:

  • You can observe leakage from the stuffing box or some other areas that would include gaskets, bearing seals and cracks or holes in the piping or pump casting.
  • You can hear an abnormal noise. You can probably “pin point” the source if you try. Sometimes you can hear air leaking into a mechanical seal or pipefitting. Vacuum leaks can be checked with smoke.
  • You can smell high temperatures and you can see evidence of excessive heat in one or more of the components. When stainless steel gets hot it turns color. If there is a question as to whether the color is on or in the metal, try to erase it with a common pencil eraser. If the color comes off, it means the piece did not get hot, something was stuck or coated on the stainless steel.
  • The following chart will give you an indication of the temperature by looking at the color of the stainless steel:
TEMPERATURE °F.
COLOR
TEMPERATURE °C
700-800
Straw Yellow
370-425
900-1000
Brown
480-540
1100
Blue
600
1200
Black
650
  • Oil will blacken when exposed to high heat.
  • You can detect excessive vibration either from the use of instruments, or one of your senses.
  • You can check if stuffing box environmental controls are hooked up properly, and in many cases tell if they are functioning correctly. You should be able to detect flow in the lines by a temperature difference between the inlet and outlet lines.
  • You can check the position of control and isolation valves throughout the system. This is especially important to check while the pump is running.
  • If there are meters available you can check :
    • Flow.
    • Differential pressure
    • Power consumption.
    • Temperature in the volute, stuffing box and bearing case.
    • Shaft speed.
    • Sight glasses will show liquid levels.
  • You can estimate if the foundation is too weak. It should be five times the mass of the hardware sitting on it.
  • If you are using cartridge seals you can estimate the face load by measuring the gap that held the retention clips

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  • On February 18, 2018