Understanding Pilot-Operated Relief Valves: Detailed Video Guide

How a Pilot-Operated Relief Valve Works(Video Teardown & Explanation)

Hey everyone, check out our pilot-operated relief valve! Today I'm gonna take it apart so you can see what's inside and how this thing actually works.

So here's our bench vise holding a socket wrench— gotta make sure the socket matches the valve's hex size perfectly. Slot the valve into the socket, loosen the back screw, take it all the way out, and then we can pull off the valve sleeve. Our technician actually custom-ground this special tool—see? Fits right into the front hole of the valve sleeve.

Be careful not to scratch that hole, okay? And just like that... it's off!

Here's what you'll find inside a pilot-operated relief valve. This part is the pilot circuit—this little triangle symbol tells you where it is. So here’s how it works: Pressure oil comes in through Port 1 at the top, flows through the damping hole in the main valve, and fills both chambers. At this point, the main valve doesn’t move—no oil gets released.

But when system pressure keeps rising and exceeds the pilot valve’s spring setting? Boom—the pilot valve opens. Hydraulic oil starts flowing through the damping hole and relieves back to the tank. That creates a pressure difference between the two chambers of the main valve. With that difference, the main valve pushes downward… —— and that opens the path from Port 1 to Port 2. That’s when a large amount of oil rushes out through Port 2 back to the tank.

So basically—it uses a small flow from the pilot valve to control a large flow through the main valve. Super precise stuff. That’s why you’ll usually see these in high-pressure or high-flow Hydraulic Systems.

Wanna dig deeper? Come hang out in my live stream— I’ll break it down even more. Thanks for watching!