How-To Test A Check Valve

This short check valve video helps explain common symptoms of a bad check valve and how to test it.

How to Test A Check Valve

Your check valve is a one way valve that keeps air inside of your tank. It is NOT located on the side of your on/off pressure switch. It is hidden. If you follow the supply air line from your pump to your tank, you will find it. Most of it is in your tank. 

Do this test first!! 

  1. Let your unit pump up. 
  2. Turn it off. 
  3. Find the supply line from the pump to the tank. 
  4. Remove the supply line from the pump head. 
  5. If you hear air coming from the tank you have a bad check valve
  6. If you do not hear air coming from the tank, then you have a leaky pressure switch. 

To remove your check valve: 

  1. Unplug the AC supply from the wall. 
  2. Remove the supply line from your pump to your tank. 
  3. There should be a larger hexagonal nut in the top of your tank, remove it. 
  4. Now you will discover your check valve. It is probably rusty. 
  5. Measure the outer threads of the portion that fits into your tank and subtract 1/4". 
  6. Measure the outer threads of the portion that the tube fits into and subtract 1/4". 
  7. You now have the MPT measurements of your check valve. 8.Look on the check valve main page and locate the style of check valve and order appropriately.