New air compressor doesn't have a pilot valve?

[bandit25]

Hey guys,

I bought a gas air compressor off of craigslist a while back, and I'm really confused by it..

Looking over it, it doesn't seem to have a pilot valve, and as such I have no idea how to set the max pressure.

Secondly, besides the belt, there is no connection between the pump and the engine to adjust the throttle.

Lastly, it looks like the pump is connected to the tank in two places. One is a larger ~1.5" connection where I imagine the air gets pumped to (not pictured). The second is a small copper line that connects to the pressure sensor on the front of the tank. Is this all connected correctly?

Thanks!

 

[Zrexxer]

Looking over it, it doesn't seem to have a pilot valve

The pilot valve is right there in the first and second pictures. Control Devices, Inc Model P25.

CDI has instructions on how to adjust on their website:

http://www.cdivalve.com/products/valves-nozzles-faq/?reference=valves-nozzles#q4

 

[bandit25]

Oh got it. It doesn't have the manual unloader toggle that I've seen on, well, every other compressor, so I didn't think it was it. How would I adjust it? And once I pick up a throttle idler control cable, where would I connect it to?

 

[bandit25]

The pilot valve is right there in the first and second pictures. Control Devices, Inc Model P25.

CDI has instructions on how to adjust on their website:

http://www.cdivalve.com/products/valves-nozzles-faq/?reference=valves-nozzles#q4

Oh. Hah.

 

[bandit25]

So it appears that this pilot valve doesn't actually have a connection for the throttle control, is that correct?

Or would I connect it to -- where the plug is [Picture 1] that is on the right T-port? (long thin copper pipe going to the pump is on the left T, stopper/plug on the right T)

 

[bandit25]

Something doesn't seem to be working.... Pressure builds up until the emergency unloader (not sure what it's actually called) engages, around 160psi.

Following the directions linked, it says to twist the adjustment screw counter clockwise to lower the cut in and out pressure. I twisted it all the way out, didn't change anything.

What I know:
On image 4, on the front face, there is that silver shaft with a black cap on top. There's a hole on the top of that cap that is blowing out a little bit of air. Also, same image ~3" below that silver shaft where the copper line goes into the pump, the elbow connection is an unloader type thing with a hole on the bottom that also blows out air. These 2 exhausts blow out the same amount of air regardless of where the adjustment screw on the pilot valve is, and blow out air immediately from >0psi. They don't seem to blow out much air, either, just little pulses.

Aside from those two, I don't notice any air discharging or hissing from anywhere at any pressure range, even with the adjustment screw all the way out. I took apart the pilot valve and cleaned it out good (didn't see any issues), didn't change anything. I'm not sure where it's even supposed to unload, because this pilot valve doesn't have an exhaust port, and the 2 exhausts mentioned earlier don't seem to affect anything.

Any ideas?

 

[Trey T]

watch the video for pilot valve adjustment

 

[bandit25]

watch the video for pilot valve adjustment

Thanks! Watched that and yeah, that's exactly how I adjusted it.

So I removed the copper line going from the left T that feeds back to the pump and left it open. I have the tank at 120psi. Moving the adjustment bolt in or out does nothing, I don't get any air going out of the T fitting. Seems to me like the check ball in the pilot valve is stuck or something? When I took it off earlier it was all really clean, though, so I'm not sure what's going on with it

 

[Zrexxer]

OK, I've been ******* all afternoon, but I finally got a chance to take a shot of how mine's plumbed. Appears to be the same valve:

 

[bandit25]

Awesome thank you!! Okay so that answers those questions.

I think that my valve is broken.. I have it apart now, and there is a ball inside it. However, it's basically seized in there and I can't get it to move at all. Broke a few mechanical pencils (only plastic rod I could find so I don't scratch the ball) trying to get it to budge...

The way that I understand this thing working: The adjustment bolt has that spring/plunger on the end of it. That spring, while under compression, pushes the plunger up to the ball, which is pushed up against the tank-inlet side opening, sealing it. Once the tank air pressure exceeds the spring force of the spring/plunger, the ball is pushed the other direction, opening that gap, and allows air to flow through to the outlet to the pump and throttle. Is this correct? If so, that ball should be able to move back and forth freely.

.... I fixed it! Woohoo! The Differential adjustment was tightened all the way down, forcing the ball up against the tank side and giving it no play. I'll re-install it and see what happens! Thank you again!

 

[Zrexxer]

.... I fixed it! Woohoo! The Differential adjustment was tightened all the way down, forcing the ball up against the tank side and giving it no play. I'll re-install it and see what happens! Thank you again!

Good deal! Glad that worked. Yes, the ball is what directs the air in the valve and it's got to move.

Your post reminded me that mine had a problem when it was brand new... Where the cross bore was drilled in the valve body, there was a little burr, which broke off and fell in behind the ball. That little sliver of brass was of course enough to jam the ball in the bore. When I disassembled it, I found the burr and cleaned it out, and it's been working fine ever since.