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Air Compressor Suddenly Won't Turn On

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  • Air Compressor Suddenly Won't Turn On

    Hello...just joined the group, hoping to get some advice on my compressor issue. I have a 0f601150ha pancake air compressor that is about a year old and not used much. Worked fine won't turn on. Obvious easy fixes tried (plugged in, reset, etc.). Anyone have any thoughts on this? Thanks!!

  • #2
    If you still have air in it, let it out then try again.


    • #3
      Is it giving you any indications at all? I mean, does it attempt to start, do you hear anything like the motor trying to kick on, but sounds strained and it just shuts off, etc.?

      Manutd is correct, if there is air pressure in the tank and more specifically in the discharge line between the pressure switch and the tank, the motor will not start as the motor cannot move against the back pressure. Try opening the drain valve at the bottom of the tank, dump the air and when completely relieved try to turn on the compressor. If it works, then once the compressor comes to full pressure, shut it off and try to start it again. If it doesn't start, then you've got a problem with the pressure switch in that the pressure relief valve (not the safety valve, that is different) is failing to dump the pressure on shutdown. Also, note that the is a check valve located at the tank where the air line feeds from the compressor discharge, and that may be fouled, thus allowing air in the tank to bleed back into the feed line coming from the compressor discharge.

      Basically the way the compressor works is that on normal start-up, there is no back pressure in the cylinder; the piston moves to pressurize the air and that pressure flows through the discharge valve into a line that feeds into the tank. At the tank, the pressure flows through a check valve which allows only air to pass into the tank (and not back out). The pressure switch monitors the pressure as it builds in the tank and upon reaching the Maximum Allowable Pressure, it will shut off the motor and at the same time activate it's pressure relief valve to remove the air in that feed line and also the cylinder. When the motor stops, you can usually hear the pressure being discharged from the feed line. The 'check valve' located at the feed point into the tank will keep the air from bleeding back out and pressurizing the feed line and the cylinder again.

      As you use air, the pressure will drop and at the point where the pressure drops below the factory set-point, the pressure switch will sense that, and turn the motor back on, and the re-pressure cycle will restart. This is a continueing cycle as you use the compressor the drive your tool or your pressurization of a tire, etc. Each time the compressor stops, the pressure switch must dump the pressure from the feed line and the cylinder... it's and ongoing process. If of course you're continueing to use the pressurized air while the compressor is running, the tank will not reach maximum pressure and the pressure switch will not intermittantly shut it down (that's where the "duty cycle" of the compressor comes in).

      When you shut off the compressor, the tank should maintain the pressure build up, until you manually discharge it through the condensate drain valve (always a good idea, you don't want condensate to build in your tank, where it will cause corrosion. When you shut off the compressor, the pressure switch should always immediately discharge the pressure in the feed line and the cylinder, instantly! If it did not, then the cylinder and feed line will remain pressurized; likewise, if the check valve leaks then pressure will bleed back from the tank and repressurize the feed line and the cylinder.

      The motor (any motor) is not powerful enough to push the piston against a pressurize cylinder and feed line, and the pressure switch will just shut off because of the overload.

      I hope this helps, I don't think I missed anything. Usually a problem description as you stated, is because of a bad pressure switch or leaking check valve. Often it may also cause for a circuit breaker to trip or the overload breaker on the compressor to trip.

      Let us know how you make out,



      • #4
        Thanks for taking the time to provide that very detailed response. I appreciate it! The last time I used it (and it worked fine), I drained all the air out of the tank when I was done. The next day I went to turn it on and got nothing. The reset button has not tripped. I don't know if it matters but when I drained the air, I didn't use the condensate drain valve. I just opened the valve at the bottom of the tank and slowly let the air out. Thanks again!


        • #5
          "Condensate Drain Valve"... sorry, just my nomenclature. In this instance, it is the little valve at the bottom of the tank that is used to drain any moisture in the tank; and, as you and I both use it, to quickly drain the air from the tank after each use. In an industrial-size compressor, there is often an automatic valve, much more complicated, that is termed "condensate drain valve" same basic function, but that only drains any moisture that has built up in the tank or someplace along an air line, usually on a drop-leg, built into the industrial air feed to multiple air tools.



          • #6
            CWS...ok. I thought you were referring to the little safety valve. The owner's manual says to pull that valve until PSI reaches 20 and then open the main valve when you drain the air out. I didn't do that. Didn't know if that may have contributed to the issue.

            Bottom line is that the tank is empty and for some reason the compressor doesn't turn on. Absolutely nothing happens when I turn it on. Just hoping someone else may have had the same problem and can provide advice on how to fix. Thanks!!