if a pilot-operated check valve (POC) does not check flow, you will see The symptoms and symptoms of a failing swing test valve are regularly audible.
When the pilot valve reaches set strain it opens and releases the strain from the dome. The piston is then unfastened to open and the principle valve exhausts the machine fluid. The manage pilot opens both to the principle valve exhaust pipe or to the atmosphere.
Pilot operated test valves paintings through permitting unfastened go with the drift from the inlet port thru the opening port. Supplying a pilot strain to the pilot port permits go with the drift withinside the contrary direction. Air strain on the pinnacle of the poppet meeting opens the seal permitting air to go with the drift freely.
Read more about the pilot valve :
https://brainly.com/question/15565472
#SPJ1