Air compressors.....keep em full or not??

[John Kain]

I have always emptied all the pressure from my tank after uses. However, I learned that one of me coworkers has pretty much left his full (pressurized) for the last 5 years.......

Who's right?

[Julio Navarro]

Good question, Ive been meaning to ask that.

[Matt Warfield]

I've heard some pretty nasty stories about tanks rusting through. I usually leave mine pressurized but... The other day I drained my 6 gallon tank and ended up with about a cup of very rusty water.

I think the climate may have a bit to do with your preference. If I were in Arizona, I'd be much less concerned than during the humid summers here in Iowa.

HTH,

Matt

[Darl Bundren]

I'd let the pressure and moisture out.

[Bruce Wrenn]

I leave mine pressurized, but I use it almost everyday. Drain water a couple of times each month. Soon I will be relocating it to upstairs and will put a cable operated drain valve on it, but will still leave pressurized. I don't leave any hoses connected unless they are serviced by a ball cutoff valve. Once when teaching school, I went to surplus property and got a 20 gal compressor that was over half full of water. Air takeoff was at top of cylinder. Tag said cycles too often- I wonder why. It was HEAVY!

[Allen Bookout]

Good question! I am not sure that anyone really know the answer. I keep seeing here that many say to drain water often and some seem to think you should let out the pressure when not in use. I had a 20gallon portable for over twenty years that I only drained every few months and kept pressurized most of the time and the tank was still good. At least it did not explode and held air. I did not run it all of the time so it was low use and that may have had something to do with it.

I am trying to take better care of my new upright but I am not really sure how much difference it makes after my last compressor tank lasted so long.

[Jim Becker]

I have an automatic drain on my compressor, so I can leave it on full time if I want. However, since I've been getting such limited shop time lately, I haven't been leaving it under power outside of when I'm actually using it for a day or so. One thing I do when I leave it on, however, is close the valve just off the compressor as I know my lines leak slightly...no sense in having it run more than necessary.

Relative to the question at hand, I believe that as long as you deal with the moisture, it's probably not going to hurt the system to stay pressurized most of the time. Regular care in that regard is very important, IMHO.

[Larry Cooke]

As long as you drain it regularly, say once a week or so, there's no need to drain all the air off. Just bleed the tank until the moisture stops then close the valve. If you power it off prior to doing so then at least there's that much less the compressor needs to compress when you use it next.

Think of it this way, the tank will rust whether there's compressed air in the tank or not. The secret is doing your best to drain the water out.

Larry

[Bruce Page]

I have an ADV on my 1½ year old IR so I leave it pumped all the time. I didn't have a ADV on my old Speedaire and I left it pumped all the time also. The old Speedaire was 20+ years old when I gave it to my son. I never had a problem with the tank.

[Ray Bersch]

My compressor is a 35 plus year old Craftsman special and I have kept it pressurized just about all of the time - now, there may have been a time when months went by and it did not have pressure because of leaks and the fact that I had a master shut off for all tool circuts in my former shop - but the point is that I keep it pressurized almost all of the time, even here in my new house where it resides in a two car garage.

Ray

[tod evans]

john, i turn the power to mine off every night but they stay pressurized. draining the tank daily is the best tank maintenance a fellow can do. changing the oil every couple hundred hours of run time is good pump maintenance....02 tod

[Stu Ablett in Tokyo Japan]

I cut the power to mine each day I leave the Dungeon. No hoses are kept attached to the compressor.

I don't use mine a lot, I drain it when I think of it, which is about twice a month.

Cheers!

[Cliff Rohrabacher]

Most of the small ( less than 10 machinists) machine shops where I have worked drained the tanks each day at the close of the day. Some did not and the large shops did not. As I recall those little shops were not airconditioned so Humidity was a constant companion.


I have considered adding the same additive to my own tank that many people add to their cast iron forced hot water furnace systems. It is supposed to stop rust.

Wnen I get a good system and trouble myself to install line dryers I likely will do just that.

[Ken Deckelman]

Jim and Bruce,
Can you please go into detail about your auto drain valves?

I would like to put one on my 80 gallon tank that I leave pressurized and powered all the time, but often forget to drain.

[Chris Padilla]

My compressor is on a 24-hour mechanical timer to ensure it doesn't kick on in the middle of the night waking up half the house! Don't ask me why I have a timer on it now! ;)

[Jim Becker]

Can you please go into detail about your auto drain valves?

Mine is an IR auto drain kit that I picked up off of E-Bay at a "very attractive" price...like about $70. If you do an "advanced search" here at SMC on threads started by me, in the General Woodworking Forum with the keyword "drain", you'll fine about four threads that I mention or talk about it.

[Bruce Page]

Jim and Bruce,
Can you please go into detail about your auto drain valves?

I would like to put one on my 80 gallon tank that I leave pressurized and powered all the time, but often forget to drain.
Ken, I think that Jim & I have the same IR brand ADV. Here’s a post on my setup.
http://www.sawmillcreek.org/showthread.php?t=17659
I love the thing and it works flawlessly.

[Mitchell Garnett]

Jim Becker's reply made me go look at that auction site - I saw a bunch of pneumatic auto drain kits for $8.90. Wasn't sure about them so I searched the net for more info and came across this link:

http://www.paragoncode.com/shop/compressor/

...just in case you are interested.

I have a manual drain but I did add an extension with an easier-to-use valve so draining isn't a big deal.

[Mike Kelly]

I have a 33 year old Sears 1 HP compressor that the drain plug rusted shut on about 20 years ago. I had to take the pressure regulator off every 2-3 years and drain a cup of water out which was a pain. About two years ago it finally developed a leak on the bottom. There was still enough steel to drill and tap a 1/4NPT hole and screw in a brass valve where the leak was. This year I welded a small steel plate over the hole and drilled re-tapped the 1/4NPT brass valve. I am not sure draining it more regularly would have extended the problems or not. I never unpressurize it. It will hold air just fine if I don't leave a tool or line plugged in that does leak. Drained weekly would surely be adequate.

[Kent Fitzgerald]

My compressor is on a 24-hour mechanical timer to ensure it doesn't kick on in the middle of the night waking up half the house! Don't ask me why I have a timer on it now! ;)

Chris, great idea!

And yes, I know exactly why you have a timer on it now. :D

[Bob Stegemann]

I leave mine pressurized but try to remember to turn it off every night. I read a thread in one of the forums some time back of someone that had a fire due to a hose breaking and the compressor running continuously until starting a fire.

[JayStPeter]

I leave mine pressured, but turn power off to it when not in use. I have an auto drain valve that is not installed because of clearance issues. Once I remount the compressor and create some clearance, the ADV will be on the 110V switched circuit I use to energize the relay for the compressor.
I unplug all the hoses when not in use since they are the only parts the kids can reach. With them unplugged, I have no leaks in the system, it will hold 125psi for months.

Jay

[Frank Fusco]

I can't answer your question from a standpoint of knowledge. But this thread reminded me that in my fathers shop (he was a professional furniture/cabinet maker) he had a large air compressor. Next to the drain valve was a big decal that read "Drain every Monday". I guess Fridays wouldn't work. ;)

[Steve Clardy]

Well. Mine stay on 24/7

I am not gonna listen to the compressor running filling up two 60 tanks every time I come into the shop in the mornings.
I only power up one compressor, which I never shut off. I have them tied together.