Carbon_One Posted July 12, 2017 Share #1 Posted July 12, 2017 My garage air compressor started dumping air at the unloader valve last week. So I ordered a new regulator assembly which has a new unloader on it. Installed it but now I'm getting the same results. Any ideas guys? Larry Link to comment Share on other sites More sharing options...
CMCOFFEY Posted July 12, 2017 Share #2 Posted July 12, 2017 Can you take a picture and tell us what all you replaced and where the air is coming from? I am a visual thinker Link to comment Share on other sites More sharing options...
slowrollwv Posted July 12, 2017 Share #3 Posted July 12, 2017 Do you have a pressure gauge on it? What is the pressure when the unloader kicks off? Link to comment Share on other sites More sharing options...
Condor Posted July 12, 2017 Share #4 Posted July 12, 2017 Drained the tank lately?? Link to comment Share on other sites More sharing options...
Marcarl Posted July 12, 2017 Share #5 Posted July 12, 2017 Drained the tank lately?? Next time can I ask this question? Oh OK, you were first!! Link to comment Share on other sites More sharing options...
Condor Posted July 12, 2017 Share #6 Posted July 12, 2017 Next time can I ask this question? Oh OK, you were first!! LOL... But not very often.... Link to comment Share on other sites More sharing options...
baylensman Posted July 12, 2017 Share #7 Posted July 12, 2017 In my old shop I had a big blackmax system. In Florida where the humidity is in the 85% to 90% every day, once every year i had to replace the POP off valve. Now I had a 175 PSI system so that may make a difference. I've had several be bad right in the box. Took them back to the local warehouse they replaced them no problem. evidently the spring plate can go weak just sitting around Link to comment Share on other sites More sharing options...
Condor Posted July 13, 2017 Share #8 Posted July 13, 2017 In my old shop I had a big blackmax system. In Florida where the humidity is in the 85% to 90% every day, once every year i had to replace the POP off valve. Now I had a 175 PSI system so that may make a difference. I've had several be bad right in the box. Took them back to the local warehouse they replaced them no problem. evidently the spring plate can go weak just sitting around I also have one of those BlackMax 60 gal upright compressors. Even operating in 25-30% humidity I have to drain the tank once a year. On mine there's a valve at the bottom of the tank. Under pressure it only takes a nano-sec to blow the moisture out... Link to comment Share on other sites More sharing options...
saddlebum Posted July 13, 2017 Share #9 Posted July 13, 2017 (edited) check the one way check valve going into the tank. The unloader valve is only supposed to drain the discharge line between the compressor and the tank, too make it easier for the compressor to start when it kicks on. If the one way check valve sticks open or has lost its seal the unloader valve will drain the entire tank. The one way check valve is usually built into the fitting at the tank that the discharge line and often the small unloader line go into. Disconnect your big line between the compressor and the tank and remove the fitting to check it. Edited July 13, 2017 by saddlebum Link to comment Share on other sites More sharing options...
Carbon_One Posted July 13, 2017 Author Share #10 Posted July 13, 2017 check the one way check valve going into the tank. The unloader valve is only supposed to drain the discharge line between the compressor and the tank, too make it easier for the compressor to start when it kicks on. If the one way check valve sticks open or has lost its seal the unloader valve will drain the entire tank. The one way check valve is usually built into the fitting at the tank that the discharge line and often the small unloader line go into. Disconnect your big line between the compressor and the tank and remove the fitting to check it. I think Saddlebum is on the right track. The compressor shows all the symptoms he mentioned. I have a 135 psi pop off valve that works properly. The unloader starts bleeding air off first on the bottom of the regulator and continues to do so till the tank is empty when the switch is turned off. With switch on it'll still continue leaking even after the motor kicks on & compressor builds pressure again, running continually at that point. I'll check that one way valve tomorrow. Thank all, Larry Link to comment Share on other sites More sharing options...
Carbon_One Posted July 26, 2017 Author Share #11 Posted July 26, 2017 Thought I'd give an update on my compressor problem. I ordered a check valve and a gasket kit prior to going to the Ontario rally. A "O" ring in the head was leaking so I ordered a gasket kit plus the check valve looked questionable so replaced that as well. Got it all back together today and everything is functioning as it should be. Thanks to all who responded here. Larry Link to comment Share on other sites More sharing options...
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