I will assume we are taliking about the "unloader valve" on the compressor.....it's job is to unload the head pressure once the compressor switches off,so that when it starts up again there is no head pressure to overcome on start-up .....it may leak a bit from sitting idle .....if it leaks a lot from your repair ,the compressor will start/stop more often .....otherwise it may clear itself up over time.....once you power down the compressor any captured air may leak out over time....
Good Luck Jim

Yes, it is the unloader valve. It says on the web site that it needs to be replaced, but I suspect that even if it doesn't clear up that it is not a danger? When I turned off the compressor after it sat for quite a long time (months) the value was releasing air. It didn't stop. In fact it didn't stop until I released all the air from the tank. My repair is not leaking at all I only replaced a tube that brings the air to the tank, I am faily certain it is ok there.
Thanks

Can anyone let me know, will I harm the compressor if I use it if the uploader value is releasing air? When on and after I turn it off. I use this machine on the average (when I feel like working with hot glass) about 3 to 4 hours at a time. I just want to be sure I won't harm it for now while I wait for parts to be available (could be a couple of weeks). I will turn it off in between using it....it won't explode or anything weird like that? Thanks, I just want to be assured before I try to use it today (hopefully)

IMO, it may cause more stress on the compressor if the valve is not repaired or replaced..
Why not disassemble it and see what makes it tick ??
There should be a pressure relief valve, somewhere, to prevent excessive pressure..
Sitting, even for several months is not good for machinery.

I could very well be wrong ? But I don't think you have a unloader valve, on the AC? Usually a unloader valve is on engine powered AC's when the pressure reaches a set amount it allows the engine to go to idle etc. You could be refering to pressure regulator valve? Anyway I have had bad luck with the pressure reg. vlaves leaking and just learned to live with a 3 day leak down, on a 80 gal comp :(

90% of the better quailty AC (electric) powered air compressors have a unloader. If not the motor has to really struggle to get going once the once the switch kicks on.

You say that you replaced the tube and used a new ferrul.
It could be a possibilty...
#1. That you placed the ferrul to far from the end of the tube and the tube is pressing against the unloader valve.

#2. You may have bent the small lever that pushes the unloader pin to release the air pressure. It should have a very small gap between it and the pin when the compressor is running.

#3. Dirt or a piece of copper could have fallen into the unloader valve and is holding the valve open.

I would first check the lever. Then remove the tube from the unloader end and check the ferrul. Next I would spray a light lube (WD 40) directly into the unloader valve. reinstall the tube. Then remove the tube from the compressor head and spray some "WD 40" into it. Hook it back up and try again.

http://www.campbellhausfeld.net/wcss...05900_1102.pdf

Here is the basic part plan for the compressor. The copper tube doesn't get near the unloader valve. I have taken it apart and looked at it, it has a small metal pin in the top that is spring loaded that goes in and out if you push it, it seems to move fine. There is really nothing else you can do with it. It is plastic and looks clean. I reinstalled it. This machine never did this before. I would leave it on for days at a time and it just waited for me to use my oxygen and then would fill up again. It didn't let off air or even make a sound. I have been told by others that they have old machines that they removed the unloader valve for lack of a replacement and that they have used them for years like this. Of course this is a fairly new unit and being so far away from civilization it makes it hard on me to get parts or any knowledgable help even. I am pretty much on my own and have to figure it out. I will have to get some WD-40 and see if that fixes things, I usually have some but I happen to not have a can right now. I will make sure to bring one the next trip to the states....always am making a new list of must haves. I know or have been told that the motor will stress if I use it with a bad unloader valve, I don't know why this would be, is it because it releases air? Or can't release air while on? I know it doesn't release air while on, because I have felt where the air comes out and nothing does, until I turn it off and then it lets it all out....even the tank air....some air comes out of the intake hole as well....

Here is a link that might be useful: parts list for compressor....

So the guy says that if I use it with a bad check valve that the motor will humm and have a hard time starting up. He says it can burn up the coils in it (whatever that is). So I guess I am out of luck....although a thought comes to my head...

When I made a new aftercooler (the copper tube) instead of purchasing a new one (due to someone pulling on that part to move it and bending it a tad) I put it back together the way it looked....on the part list it is #17. Anyway it had something that looked like a rubber ferrule #16. Could it be that it had a metal one there? and the rubber one? If so could that make the check valve #15 not work properly? I do have an extra metal ferrule here and could take the copper tube off and install the ferrule to see if that fixes the problem? What do you think? I do not want to burn up the motor and from what they say it seems that would happen eventually. I understand that the Unloader valve is not broken at all and luckily for me I have only turned it on briefly twice so things should be ok for the most part...but if I can fix it today I would be thrilled..instead of waiting to go to the states...

Thanks again

You have a bad check valve and YES it can and will harm the compressor.
It will run too much and has to start under load.
Replace the check valve and you should be OK.

Everyone is talking upload valve, BUT what is even a more common problem is the check valve at the tank. On the smaller compressors it is located at the tank it screws in, has two lines on it, on the smaller compressors, it has a 1/4", and a 3/8" line, the 1/4 goes to the switch and upload valve, the larger one goes to the cylinder head of the compressor pump.When it reaches the correct high limit the up loader valve kicks off the compressor, at that point the air pressure is taken of the head so it can restart easy when the pressure gets to the low limit, but at that point the check valve moves to a closed position after the head bleed off, to not keep draining air. Without good maintenance that check valve gets rusty, and junked up. When it does the little plastic flap that closes off the air gets hung-up and the spring can't close it. Take off the two lines, and remove the valve, spray some WD40 in it, and try to work it free, most the times you can, if not pay the $25 fr a new valve. When this check valve sticks the air is released and leaking at the up load valve, so it becomes misleading and most look at the up load valve, not the check valve. I just went through all this with my compressor, after trial and error....Hope this helps, Tom

Everyone is talking upload valve, BUT what is even a more common problem is the check valve at the tank. On the smaller compressors it is located at the tank it screws in, has two lines on it, on the smaller compressors, it has a 1/4", and a 3/8" line, the 1/4 goes to the switch and upload valve, the larger one goes to the cylinder head of the compressor pump.When it reaches the correct high limit the up loader valve kicks off the compressor, at that point the air pressure is taken of the head so it can restart easy when the pressure gets to the low limit, but at that point the check valve moves to a closed position after the head bleed off, to not keep draining air. Without good maintenance that check valve gets rusty, and junked up. When it does the little plastic flap that closes off the air gets hung-up and the spring can't close it. Take off the two lines, and remove the valve, spray some WD40 in it, and try to work it free, most the times you can, if not pay the $25 fr a new valve. When this check valve sticks the air is released and leaking at the up load valve, so it becomes misleading and most look at the up load valve, not the check valve. I just went through all this with my compressor, after trial and error....Hope this helps, Tom

Tom - you just responded to a 2 year old post. Maybe they'll still see it, but just sayin'......