Compressor justification?

[Charc]

So the TD turned on the compressor during a work call on Saturday, and left it on. Evidently to test it to "see if it works" because "it won't hold air". So he left it on for the 6 or so hours during the work call. I came in Tuesday afternoon. (72 hours later, compressor still cycling to maintain pressure [unused{for months} since it was charged, but still charged since Saturday]). I figured why wear down the equipment, waste power, and leave condensation in the tank? So I switched it off, and opened the release valves. I left a note to the TD informing him of the change of status. He sorta jokingly sorta angrily brought it up, and mentioned he was still testing it by leaving it running...? I don't know much of anything about compressor maintenance besides switching 'em off and opening valves at the end of the day, so I'd like to know some of your thoughts on the situation.

[thelightingmancan]

I have a compressor in my wood shop, and I have it on a timer, so it runs once a day when I am not using it. Since it is at my house, I do use it for lots of small things. It is a 20 gallon tank, so it takes a while to charge but, if you have a smaller tank this might not matter to you. In my opinion, and I'm no expert either, but leaving the tank at pressure reduces stress on the metal, and makes life easy.

[Charc]

Originally Posted by thelightingmancan

I have a compressor in my wood shop, and I have it on a timer, so it runs once a day when I am not using it. Since it is at my house, I do use it for lots of small things. It is a 20 gallon tank, so it takes a while to charge but, if you have a smaller tank this might not matter to you. In my opinion, and I'm no expert either, but leaving the tank at pressure reduces stress on the metal, and makes life easy.

Just to clarify, it wasn't left on to use (at all) just to "test". And for a small tank, it takes what, 5 minutes to charge? (As you can tell, I'm not familiar with it, we've used it once in 18 months... 18 months ago.)

[derekleffew]

Originally Posted by thelightingmancan

I have a compressor in my wood shop, and I have it on a timer, so it runs once a day when I am not using it. ...

My 2.5gal compressor is on a timer also, but only so it won't annoy the neighbors. When I remember, I switch it to "off," but usually it sits at 90psi for months between uses. Takes 2.0 minutes to go from zero to fully charged.

[icewolf08]

If the compressor motor was just running without stopping for all that time, then you did the right thing turning it off. If the motor never stopped running then you have a pretty serious leak in the system somewhere. The motor should run until you reach operation pressure, then shut off. When the pressure drops below a certain point the motor should kick on again. From the way you tell the story, it sounds like your compressor, or whatever it was connected to has quite the leak.

We leave our compressor powered almost all the time. We turn it off during shows, and if we remember at the end of the work day (and any time that it just starts driving us nuts and is not being used). There are a few small leaks in the system, so the motor kicks on every couple hours if no one is actually using any pneumatic tools. When people are using tools it kicks on more frequently.

[Charc]

Thanks Derek and Alex, both are interesting responses.

Derek, you leave yours pressurized? So you don't buy in to the tank corrosion from water? Also, if it takes 120 seconds, why not just open the release valve for the couple month hiatus?

I'm sorry if my original post wasn't clear, but there was no apparent serious leak with the tank, not even an audible hiss. The motor did run every once in awhile (annoying), but not enough to raise any eyebrows.

Learning from observation (and hands on), at my internship there were two compressors. A 60 gallon unit in the shop, and a smaller portable unit for use in the theaters. Both of these units were powered off and had pressure released at the end of the day.

The reason why it was being run is the TD thought there was a serious leak issue, and apparently was monitoring the compressor by leaving it on through the work day. I don't see how an extra 72 hours would prove anything, especially because with the compressor on, it's just going to keep shoving more air in.

[thelightingmancan]

My compressor runs about every 15-18 hours, so it drove my parents nuts. They would wake up, but I sleep right through it, but I got the timer out of it, which has all of my shop equipment on it so someone can't accidentally start something. I know it sounds strange, but our neighbors always think I'm in there and want to borrow something, or talk, but a little kid neighbor could go in while I have the garage open and mess with stuff, cutting fingers off or something. It's a small community, nobody really locks anything, and they all leave cars unlocked.

I still think filling and draining puts undue stress on the metal, and I do drain the water valve once a month, but nothing really comes out.

[Charc]

Originally Posted by thelightingmancan

My compressor runs about every 15-18 hours, so it drove my parents nuts. They would wake up, but I sleep right through it, but I got the timer out of it, which has all of my shop equipment on it so someone can't accidentally start something. I know it sounds strange, but our neighbors always think I'm in there and want to borrow something, or talk, but a little kid neighbor could go in while I have the garage open and mess with stuff, cutting fingers off or something. It's a small community, nobody really locks anything, and they all leave cars unlocked.
I still think filling and draining puts undue stress on the metal, and I do drain the water valve once a month, but nothing really comes out.

That interesting, I've felt noticeable spitting and wetness when draining tanks, not to mention what seemed to have been a chunk of ice inside a tank, clogging up the valve.

[derekleffew]

Originally Posted by charcoaldabs

...Derek, you leave yours pressurized? So you don't buy in to the tank corrosion from water? Also, if it takes 120 seconds, why not just open the release valve for the couple month hiatus?...

This is Las Vegas in the desert, where average relative humidity is around 6%. A friend with a 30gal tank, opens his once per year, and rarely gets more than a few drops, if that.

[Van]

******* Danger Warning Danger Will Robinson*******
A Compressor is technically referred to in most OSHA type safety manuals as a "Charged Battery" Most states safety regs requires you to relieve the pressure form the tank every night. When not in use a compressor should be de-pressureized. Metal fatigue is not a valid excuse for storing a pressurized vassel. A compressor should be drained weekly if not daily. Now Derek, in Vegas, is right that he can go for much longer given the average relative humidity, but those of us living in more hospitable climes need to be much more vigilant in compressor maintenance.
I don't think it's worth getting into a heated discussion with your TD about though. But if he was checking for leaks that shouldn't take more than an hour. Charge it up. Turn it off. Come back in an hour and see how mor pressure drop there is.