Do you leave your compressor pressurized?

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  • bing!
    Forum Newbie
    • Apr 2010
    • 33

    Do you leave your compressor pressurized?

    I have no experience with air compressors. I got a Ridgid twin tank 4.5 gallon compressor in trade a few months ago. I have since fixed her up, replaced a few screws, tightened things up to reduce vibration and bought a basic air kit.

    My questions is, the manual says to de-pressurize and drain water from the compressor for storage. My neighbor, "the tool guy", says to leave the pressure on indefinitely, just turn the motor off.

    What do you do?

    Thanks. /bing
    Last edited by bing!; 04-29-2010, 08:47 PM.
  • Uncle Cracker
    The Full Monte
    • May 2007
    • 7091
    • Sunshine State
    • BT3000

    I do not leave mine on all the time, as I have a piping network with enough quick connects that it leaks down and cycles the compressor every hour or so, and it's loud...

    I have a tube and ball valve piped to my compressor drain, and I open it briefly if I have used the compressor for any appreciable time. With the humidity here in FL, it's hard not to get some condensate build-up from time to time, but I have been on this same tank for nearly 20 years without a rust problem.


    • charliex
      Senior Member
      • Mar 2004
      • 632
      • Spring Valley, MN, USA.
      • Sears equivelent BT3100-1

      I don't depressurize mine even and I don't use it every day. I do drain it about once a month. I don't leave the switch on because when it kicks on it scares the **** out of me.


      • Ed62
        The Full Monte
        • Oct 2006
        • 6021
        • NW Indiana
        • BT3K

        I drain mine after using for the day. The petcock stays open until I'm ready to use it again.

        FWIW, my neighbor, whose opinion I have a great respect for, doesn't drain his. But I think leaving the tank with water in it, invites problems.

        Do you know about kickback? Ray has a good writeup here...

        For a kickback demonstration video


        • Rich P
          Established Member
          • Apr 2003
          • 390
          • Foresthill, CA, USA.
          • Powermatic 66 (1966 vintage)

          I have a 30 year old Craftsman unit that I leave pressurized all the time. I periodically depressurize and drain it but usually don't get much condensation. Here in the Bay Area it's pretty dry. Went not in use I also switch it off...if it kicks in when you're not expecting it, it can give you a start.
          Don't ever ask a barber if you need a haircut.


          • LCHIEN
            Internet Fact Checker
            • Dec 2002
            • 21117
            • Katy, TX, USA.
            • BT3000 vintage 1999

            i turn mine off but don't bleed it down.
            when i drain it I drain it with pressure on it until it no longer drips water then close the stopcock leaving the remaining pressure in it.

            When i come back a few days later apparently it leaks enough it'll be at zero pressure more or less.

            I don't leave it powered on
            it'll come on when the pressure falls as it leaks, that'll be noisy and power wasting.
            If something comes loose and springs a leak as piping might do when pressurized, it'll make a mess and your motor will run continuously until you find it. If a hose comes loose it can do a lot of damage whipping around unattended for a long time.

            Doesn't take long to refill the tank from off.
            Last edited by LCHIEN; 04-29-2010, 10:01 AM.
            Loring in Katy, TX USA
            If your only tool is a hammer, you tend to treat all problems as if they were nails.
            BT3 FAQ -


            • LinuxRandal
              Veteran Member
              • Feb 2005
              • 4889
              • Independence, MO, USA.
              • bt3100

              Both. Drain the portables so I am not driving around with a pressurized tank, and leave the fixed compressors.
              She couldn't tell the difference between the escape pod, and the bathroom. We had to go back for her.........................Twice.


              • dbhost
                Slow and steady
                • Apr 2008
                • 9261
                • League City, Texas
                • Ryobi BT3100

                Your neighbor either has no clue about how pnuematic tools work, or he wants you to ruin your compressor. The idea behind draining the pressure out is that air contains water, when it compresses the water drops out of suspension, and in turn, if left in the tank will rust out that compressor quick...

                Take a look at what the auto repair shops do at the end of each work day. They throw the breaker on the compressor circuit, and then bleed the lines and compressor tank. Each and every day, which usually takes a tech 15 minutes or so of billable time to do... In the evening. Then in the morning they reverse the process and have to wait until the compressor comes up to full pressure before they can get to work and start making money.

                If guys billing $50.00 plus an hour as a regular part of their practice take the time to blow and charge the tanks, there is a REALLY good reason for it...

                Of course YMMV depending on your climate... Here in coastal Texas the air is almost a liquid anyway...
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                • LarryG
                  The Full Monte
                  • May 2004
                  • 6693
                  • Off The Back
                  • Powermatic PM2000, BT3100-1

                  charliex's practices most closely match my own. I used to faithfully drain the tank down every day, as Ed62 does. After a while I tired of that little chore, and noticed that very little condensation would drain out even after two or three weeks. I generally assume that the manufacturer knows his own tool design better than anyone else, but the recommendations in a manual have to allow for a lot of variables. For some owners, "storage" might mean two weeks. For others it might mean two years. So I would suggest developing your own schedule, depending on your frequency of use and local conditions.

                  One thing to watch out for: on some compressors, such as my Porter-Cable 6gal pancake, the drain petcock is not at the lowest point of the tank. Tilt the compressor as necessary to ensure that any accumulated water actually does drain out.


                  • pecker
                    Established Member
                    • Jun 2003
                    • 388
                    • .

                    I don't drain mine daily, as it would be a real nuisance to wait 5 minutes for it to charge back up just to blow a little dust off something.
                    Even draining it once a month only produces about 1/4 cup of water.

                    To keep the connected lines from bleeding down the air tank when not in use, I removed the quick disconnect right at the output of the regulator, and inserted a ball valve. When I'm done for the day, I close the valve and it maintains the charge in the tank.

                    Mine's a portable, but not real portable


                    • sweensdv
                      Veteran Member
                      • Dec 2002
                      • 2860
                      • WI
                      • Baileigh TS-1040P-50

                      Other than an occasional emptying for maintenance purposes I always leave my compressor's tank full of air. I do shut off the power switch and back the pressure regulator back down to zero but I also found emptying the tank all the time to be just a big pain. The reason I set the pressure regulator back to zero is that the quick connects would leak and drain the tank in a day or two and this eliminates that from happening.
                      "Have a Great Day, unless you've made other plans"


                      • cabinetman
                        Gone but not Forgotten RIP
                        • Jun 2006
                        • 15216
                        • So. Florida
                        • Delta

                        I leave the tank pressurized. My air system is set up similar to this layout. I only have a ball valve at the output from the tank (mine is a vertical). The regulator and filters are piped a distance away.

                        When I'm done for the day, I shut off the air valve and turn off the power to the motor. The tank doesn't leak, so it will hold the air. As for draining, I may have to do that daily depending on the humidity. I do that with pressure in the tank to help blow out the gunge at the bottom if any.

                        If the water is allowed to build up, it will reduce the volumetric capacity of the tank.


                        • SHADOWFOX
                          Veteran Member
                          • May 2005
                          • 1232
                          • IL, USA.
                          • DELTA 36-675

                          I only have a PC pancake compressor so I drain it when not in use and unit is left unplug unless I am using it.

                          "The first key to wisdom is constant and frequent questioning, for by doubting we are led to question and by questioning we arrive at the truth." -Pierre Abelard 11th Century philosopher.


                          • cwsmith
                            Veteran Member
                            • Dec 2005
                            • 2745
                            • NY Southern Tier, USA.
                            • BT3100-1

                            I've spent most of my life in the employ of a compressor manufacturer. As DBHost stated, the compression of air will cause any moisture to condensate (fall out) in the tank. If left in the tank, it will cause corrosion and the chances of a tank leak or burst is increased... increasingly so as the unit ages.

                            I have two compressors... the small one only takes a minute or so to charge so I open the drain valve after each daily use and let the discharge blow out any moisture. I then leave the tank drain open, until I need to use it again.

                            On my larger 33-gallon, it takes some time to fill fully pressurize that tank. So, there I don't blow off the pressure every day. But, I do open the drain valve after each daily use to drain off any condensate. I then shut the valve and keep the remaining pressure.

                            Again, it is absolutely essential that you ensure that no condensate is left in the tank for any period of time. The inside of the tank is not treated to prevent corrosion and I guarantee you that you do NOT want to be around should your tank ever rupture. Usually such tanks only leak, but "ruptures" do happen and you don't want to be there. Keep the tank drained, for a small 4-1/2 gallon receiver, it should fully pressurize within very few minutes.

                            Think it Through Before You Do!


                            • jdon
                              Established Member
                              • Feb 2010
                              • 401
                              • Snoqualmie, Wash.
                              • BT3100

                              Anybody have suggestions about how to dry out (and keep dry) the tank after draining?

                              I always seem to get condensate in my compressor (HF 8 gal), so always relieve pressure by opening the drain petcock. However, the tank interior never seems to dry out (even leaving the drain valve open between uses). I'm afraid that with a moist interior, corrosion is going on even though I've drained as much water as I can. Maybe a heating cable wrapped around the tank exterior to promote evaporation???