How To Prime A Centrifugal Pump

18 December 2014
 Categories: Industrial & Manufacturing, Blog


Unless you are using a self-priming centrifugal pump, it is crucial that you manually prime it from time to time. These pumps can become filled with gases or air, which can be detrimental to the operation of the pump. When you do not prime it, it will eventually lose suction pressure, which will lead to the pump being unable to lift the water. Eventually, this could cause overheating and complete failure of the pump. Despite what you may believe, it is actually easy to prime your centrifugal pump. There are various methods of how to perform a pump priming, which are described below.

How to Prime a Centrifugal Pump

If you have the instruction manual that came with your pump when it was purchased, then it should have directions on how to prime the pump. However, if you have misplaced this manual, there are a couple of different ways you can do it. You can use a suction supply source below or above the pump itself. Here's how to do both:

1. Using a Suction Supply Below the Pump.

  • This does require the installation and use of a foot valve (also known as a check valve) within the suction piping. The purpose of the foot valve is to ensure that liquid does not drain from the suction piping.
  • In order to prime the centrifugal pump, you need to fill the pump with fluid from an outside supply source. Examples of outside supply sources may include a pressurized discharge line or a specialty priming pump. 
  • The pump suction should have pressure placed on it.
  • Make sure that the discharge isolation valve is securely shut. This valve is located roughly a foot or two from the pump on the side where the water is being discharged.
  • Next, you will want to loosen the top air vent, which is found on top of the centrifugal pump's casing. When you do this, it will let the fluid briefly escape.
  • Once the liquid has left the air vent, close the vent and then the supply line.

2. Using a Suction Supply Above the Pump.

  • The suction isolation valve should be opened slowly. This valve is located between the water source and the pump. This step is done to isolate the pump from the rest of the system in order to properly prime the pump.
  • Next, you will want to ensure that the air vents on the discharge and suction piping are opened.
  • Make sure that the valve and vents stay open until all liquid has come out.
  • When no more fluid is coming out, you can then close the air vents and the valve.

Don't forget that you should fill the centrifugal pump with fluid before you ever start it up. This is to avoid unnecessary damage to the pump and its components. Hopefully, this information has helped you to prime your centrifugal pump so that it continue operating at its prime. If you need more information about priming your centrifugal pump or maintaining its efficiency, give a local industry professional a phone call.