We are installing a "PTO wet kit" on our truck.
The kit, that I bought at a truck parts store, consists of a Muncie PTO, 13 GPM gear pump, and a pressure relief valve with a cartridge similar to Sun RPGC-LAN. I say "similar to" because the actual model is a fixed pressure RPGC-L2500N, but it is hard to find anything in google about that model number. RPGC-LAN is a number that is easier to find.
I had a tank that I put to use.
Anyway, we did a first test of the system, with the output and return hoses connected directly to each other. No problem.
Then we left the hoses disconnected, so that there was no circuit, and proceeded to run the pump to test the relief valve at full pressure and to warm up the oil quicker.
At first everything was great, pressure held at 2500 PSI, everything was flowing. After a while, though, something happened and pressure dropped to 500 psi, then more.
I started looking. The pump pumps with good flow, I know this because I pumped some oil into a bucket.
Took out the pressure relief cartridge. I found out, to my surprise, that it is very easy to puch the piston in with a plastic pen. If it is a 2500 PSI valve, it should have taken a force of several hundred pounds. Instead I can easily do it by hand.
The picture is here:
I do not really understand what could have happened and why this valve could fail and become so easy to open.
Would anyone have any idea? What could it be?
Thanks
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