Midlife gets the prize it appears. I tossed my problem over on the "Garage Journal" forum as well. A few guys had these Harbor-Freight compressors and have had to clean and/or replace the check valve out of the tank, that is in hte line before that switch bleeder valve. I'll try cleaning it this evening, they believe dirt or other got into it sticking it up, constanstly sending air to that switch bleeder. Here's one reply:
This is exactly the problem. The check valve usually will get a little piece of trash in it and stick open allowing the air in the tank to bleed off and drain the tank. The air is coming out of the pressure pop off valve that allows the 'head' pressure to bleed off after the contactor has opened. This allows the compressor to start up quickly the next time the contactor closes and does not have to fight or 'strain' against the pressure of the tank. Turn the breaker off for the compressor, drain the tank and remove the line going from the pressure pop off on the contactor assembly to the check valve on the tank and then remove the check valve that is screwed into the tank. Some check valves have a small internal snap ring that you can take apart and clean the seat then reassemble and reinstall. I generally keep a spare on hand at work because it happens every several months or so. I throw the spare in and then disassemle and clean the spare and throw it into the toolbox for next time. Quote:
Typically there is a valve plate assembly. One valve opens to let air in then closes on the compression stroke, the other (to the receiver) opens on the compression stroke and closes on the intake stroke. Ok so far, this is the obvious.
There is another valve that automatically releases pressure on the head of the unit each time the pressure switch stops the motor. This allows the motor to restart with zero head pressure. This is the hiss of air that you normally hear when the motor stops. This is the "bleeder valve" you are talking about. It always released air, just not the whole tank. I think your problem is with the valve plate in teh head.
Try this:
1) Turn compressor on and as you get to around 70psi, pull the plug.
2) Does it hold pressure. If no the bleeder switch is stuffed. If yes, leave unplugged and turn the compressor of using the switch. A small amount of air should released from the head. If all air is released, you "probably" have a problem with the valve plate in the head.
