Compressor draining

[John Coloccia]

Do you guys completely empty the compressor every night, or do you just open the drain until water stops coming out, close it and call it a day?

[Jeff Monson]

John, we have 2 90gal. compressors at work, we drain them once a week. We installed black pipe extensions with 1/2 turn gates, makes draining them a very simple and quick job. My compressor at home 30 gal. gets drained maybe once a month.

[Ray Newman]

Even though the 25 gallon compressor tank has Teflon lining, I completely empty the tank of air. Some opine that is overkill, but I look at it as cheap and easy preventative maintenance.

At first, I closed the valve when water stopped draining. Then one time I noticed that more water started to drain after it stopped and air was still draining. No air; no water.

[del schisler]

once a month . I have i belive a 20 or 30 gal. works for me. I take it out and open up the valve and with air the water come out very fast. I tilt the tank back and forth so water still blow's out than when it is through so are you

[Bob Wingard]

I installed one of these, maybe 8-9 years ago ... ... ...

http://www.grainger.com/Grainger/WILKERSON-Pneumatic-Auto-Drain-4KT04

it drains itself, maybe a dozen times a day or more ... but only for a few seconds each time.

[Myk Rian]

Whenever I remember to, or once a month. Whichever comes first.

[Gene Howe]

Usually, after each day of use. Sometimes, I forget.

[David G Baker]

I have a portable compressor that I don't use very often, I drain it after every use. When I managed a motion picture lab I had automatic drains that opened up every time the compressor cycled on. Once a year I had an inspector evaluate the tank for wall safety as was required by code in San Francisco CA. I have a couple of auto drains and oil separators that I am going to install when and if I set up a large stationary compressor that I have had for several years but haven't put on line yet.

[John Coloccia]

So I guess the general consensus is to drain the tank of water, but it's okay to leave it filled with air otherwise.

[Steve Jenkins]

you got it

[mickey cassiba]

John,et al... please be aware that rapidly expanding air cools quite rapidly. when expanding through a small port or nozzle it can drop to 32 F quite rapidly, thus freezing any water trying to pass through. If you shut the cock at the first sign of sputtering, or even complete airflow you may not be draining all of the water from the tank. Also do not attempt to 'test' this by holding your hand in front of the nozzle. This can result in a severe injury...ice crystals embedded in your flesh.There is a scientific name for this effect that I never bothered to learn...it's the same effect that allows your air conditioner to cool the air passed through the coil. I drain my 4 gallon at the end of every day. The small tank can be refilled in minutes. The larger tanks I managed at work were drained every week.
Mick

[Scott T Smith]

I installed one of these, maybe 8-9 years ago ... ... ...

http://www.grainger.com/Grainger/WILKERSON-Pneumatic-Auto-Drain-4KT04

it drains itself, maybe a dozen times a day or more ... but only for a few seconds each time.

+1, except that I bought mine at McMaster Carr. It was about 30% less than Graingers...

[Brian Penning]

I treat my compressor the same as my TV. I leave it on. ;)
That way I can get something newer and better sooner.:D

[Tony Bilello]

I drain mine according to humidity. If it is really humid, I will drain it completely every night. If the ambient air feels dry, I wont drain the tank at all-just the filter.

[Clint Olver]

I drain mine completely every night, then tighten it back up in the morning before I turn it on.

C

[Thomas Canfield]

I want to again caution anyone using a pancake type compressor that just opening the valve will not drain the tank. You must tip the tank to make all the water go to the drain. Left on its feet, there is possibly about an inch of water in the bottom of the tank. That is a bad design and I will keep saying it until the manufacturers get their act together and either tip the pancake or move the drain to the bottom of the tank.

[Gary Hodgin]

I have a small 13 gallon compressor that I use infrequently. I drain it and leave the plug loose after each use unless I know I'll be using it the same day. Might be overkill but normally after I use it I don't really know when it'll be used again. I've had it for about 10 years (Campbell-Hausefield) with no problems.

[Gary Hodgin]

I have a 13 gallon Campbell-Hausfeld that I use infrequently. I drain it after each use unless I'm pretty sure I'll be using it again the same day. Probably overkill, but I haven't had any problems in the 10 years I've had it. I leave the plug loose until I need it.

[mickey cassiba]

I have a small 13 gallon compressor that I use infrequently. I drain it and leave the plug loose after each use unless I know I'll be using it the same day. Might be overkill but normally after I use it I don't really know when it'll be used again. I've had it for about 10 years (Campbell-Hausefield) with no problems.
Down here in south Tejas, we have a small wasp that likes to build it's nest in small holes. More of a 'dauber' to you northern guys. Their cement like mud has been known to keep fire extinguishers from firing. Leaving the cock open is an invitation...it's bad enough when they block the outside orifice.

[Tom Esh]

So I guess the general consensus is to drain the tank of water, but it's okay to leave it filled with air otherwise.

Yeah, purging the water is the important part. I try to do it daily. Decompressing the tank just wastes the energy it took to pressurize it.

[Bruce Page]

John, it's been six years since I installed my ADV on my new IR compressor and I have never needed to drain the tank once. I just cycle the ADV once or twice when I'm using air and it is always crystal clear. IMO, it's crazy not to have one of these installed.
http://www.sawmillcreek.org/showthread.php?17659

[Curt Harms]

Yeah, purging the water is the important part. I try to do it daily. Decompressing the tank just wastes the energy it took to pressurize it.

Not only waste energy but I wonder if pressurizing/depressurizing tanks daily could cause fatigue failures. I'm not familiar with compressed air tank engineering but I know that pressurized airplanes' lives are determined partially by cycles i.e. number of pressurize/depressurize cycles contributing to metal fatigue. One reason DC-3 are still flying is that they're not pressurized. Compressor tanks are built heavier than airplane pressure vessels but the principle seems like it'd be the same. Fewer pressurize/depressurize cycles=good.

[Kent A Bathurst]

+1, except that I bought mine at McMaster Carr. It was about 30% less than Graingers...

Thanks, Scott - I've got that one in my gunsights now....

[David Hostetler]

My first career was as an auto / diesel mechanic (Everything from Bulldozers to Ferraris, literally... BTW, I HATE Italian cars after having to fix them!) and we had typically 60 - 90 gallon compressors in the shops. One of my nightly duties was to power off, and drain the compressors completely. This was particularly important here in Houston where the air is so stinking humid. In my home workshop, I have a simple Central Pnuematic 2HP 8 Gallon cheapie compressor. I do not drain it as I should, mostly out of forgetfulness. Actually it is now pressured up holding air from Saturday that I need to bleed off...

I really need to pull the OEM bleed valve off of this thing, put a black pipe 90 on there, and install a ball valve so that opening / closing the bleeder valve isn't so much of a chore. Just flip a lever instead of fiddling with the petcock valve. I know HF went cheap there, but this is a pain in the tail! And it's not just HF compressors I have seen like this. I have seen the Porter Cable, and DeWalt compressors set up with the same style bleeder valve. Industry standard nastiness on small compressors I would think...

I honestly would much rather just open the valve until the water is gone, then close it up. No real need to blow out all the air. Might make things easier on the seals in the long run, but I doubt it. Plus like others have mentioned, it is a waste of time, and energy to have to recompress / refill the tank(s) the next usage from dead empty...

[Steve Ryan]

I had to build a crate about a year ago. 10HP screw connected to an 80 gal tank about 4 feet below it. 50 feet of hose on the floor. Had not used that hose for about a year, but used the compressor a lot. Plugged the const nail gun in and ignored the funny sound it made as it filled with "air". First nail went halfway in and water sprayed from the exhaust. What happen next was just pure dumb. Grabbed the gun backwards with my left hand and pulled the quick connector off. Male end on the gun was pointed at my right arm and right chest. Let me tell you this, a spike gun half filled with pressurized smelly oily stinking water will ruin your shirt. Took about an hour to drain the tank.

[Neil Brooks]

:rolleyes:

Guilted me into it.

Don't remember the last time I drained mine, but ... I do, now ;)

Gonna' look into an auto drain valve, like the ones already mentioned. One less thing to keep track of, in the shop :)

[Charles Lent]

I leave my 5 hp 80 gal system on 24/7, but I unplug all rubber air lines after each use. Pressurizing and de-pressurizing the tank every time I want to use it is not a good idea, so I avoid doing it. I just make sure that the whole system is kept as leak free as possible to avoid cycling when it isn't being used. The condensate gets drained about every month in the warmer weather and about every 3 months in the colder weather.

Charley

[mickey cassiba]

Let me tell you this, a spike gun half filled with pressurized smelly oily stinking water will ruin your shirt.

Not to mention your underwear:eek:

[Chuong Nguyen]

I have an IR 5HP 60 gallon A/C that I had for about 10 years now and will just drain the water on average once a month. Water comes out crystal clear everytime.
I also have a portable Craftsman 30 gallon A/C, and initially didn't drain it immediately, so I go to drain it a week later, and the water came out rust color. So I now drain that after each use.

[Matt Day]

I just picked up an auto drain kit from HF, and will install with copper fittings rather than the tube. I've seen some good reviews on it online.

My local HF had the kit on clearance for $1.87 (which includes a 20% off coupon).

[Jim Becker]

My compressor is never, um....de-compressed. I do have an automatic drain system on it, however, to keep moisture from accumulating.

[johnny means]

I drain mine when I start seeing water at my end of the hose:o I keep tellin myself I should do better.:D

[Brian Penning]

Aren't most of those drain valves something like a 1/2" from the floor and pointed downwards?
I know on my old PC pancake and present Makita compressor it is.
How do you install the ADV?

[Byron Trantham]

+1, except that I bought mine at McMaster Carr. It was about 30% less than Graingers...

+2, except I got mine free from my brother-in-law! :-)

[Matt Day]

Aren't most of those drain valves something like a 1/2" from the floor and pointed downwards?
I know on my old PC pancake and present Makita compressor it is.
How do you install the ADV?

The stock petcock (drain) on my CH horizontal compressor is about 1.5" from the floor. I'm in the middle of installing my HF ADV, and the only thought was to put a 2x4 under both the front and wheels to raise the compressor and still allow water to drain. I though about hardpiping it out, but I figured the ADV needs to be at the lowest point. Any suggestions are appreciated.

[Peter Hanson]

Anyone have the part number for the HF ADV - can't seem to find it on their web site...

Thanks!

[David Hostetler]

The petcock on my HF compressor is 2" off the floor. (I measured it when I started thinking drain valves...).
FWIW, I still haven't drained mine from this weekend...

[Chip Lindley]

Those little "finger-getter" petcocks were installed in the most inconvenient place by Satan himself! Replace it with a 1/4" 90 degree nipple and a length of 1/4" pipe so a ADV can be threaded on. It is really worth the effort!

These are pricy from commercial sources but can be had verrrry reasonably if you hawk eBay for one. I installed a brand new Ingersoll-Rand ADV and Norgren regulator on my 60 gal. Quincy for cheap!

The I-R auto drain has a timer to set the blow duration in seconds, and interval from 1 to 60 minutes. Really Neat! That open exhaust port can be piped out through a wall to reduce noise AND water in the shop.

[Chris Tsutsui]

So is the purpose of draining water to prevent corrosion on the inside of these tanks? I wish more tanks were well coated... I know mine isn't.

I wonder why cathodic protection is never used in conjunction with these other drain methods for compressed air tanks...

Securing aluminum to the bottom of the tank can sacrificially protect a steel tank bottom (Galvanic). Basically the aluminum will sacrifice itself to protect the bare steel, but the aluminum has to be submerged in the condensed water (if there is any). You could insert the steel rod in a pipe that gets attached to the drain valve. Or fabricate a drain valve that has aluminum rod in it, or manufacturers could weld a bracket in the tank bottom that aluminum anodes could get bolted to.

Another idea is to use a non-evaporative fluid such as aliphatic alcohol on the bottom of the tank will prevent evaporation of the settled water. This fluid is lighter than water, floats on the top, and prevents the water from evaporating and causing surface rust.

BTW, there may be pitfalls in these ideas as I just shot these out there as food for thought.

Personally I like the idea of the auto-drain, though a sacrificial galvanic cp system could leave water in there and the tank will be protected.

[mickey cassiba]

Lot's of great ideas...but for me and my $90 compressor, opening my (self installed ) ball valve just works. I worked in maintenance for a while at DeVilbiss, before moving up the road to Porter Cable( all now divisions of Stanley/B&D). The bottom line there was not about making efficient, long lasting compressors...it was about making lots of bucks, quickly. I suspect some of the higher end labels(IR, and Quincy) have pretty much the same motivation. Besides, if the unit won't wear out, how are they gonna sell you another in a few years? Capitalism 101.

[mickey cassiba]

The stock petcock (drain) on my CH horizontal compressor is about 1.5" from the floor. I'm in the middle of installing my HF ADV, and the only thought was to put a 2x4 under both the front and wheels to raise the compressor and still allow water to drain. I though about hardpiping it out, but I figured the ADV needs to be at the lowest point. Any suggestions are appreciated.

If your pump is an oil lubricated one, you need to maintain the pump alignment...if it's an oil less unit you can run it upside down if you wish:)

[Mike Harrison]

Mine has been "on" for ten years in this shop. I drain it once a week during late spring, summer, and early fall. Change the oil at Christmas time. I installed a street el, piece of 1/4" pipe, and a ball valve for draining.

http://i670.photobucket.com/albums/vv62/mikeinkcmo/WW%20tools/Air%20Compressor/Aircomp1.jpg

[Jim Foster]

The pressurized tank for compressors will be/should be designed for infinite life, otherwise it's a bomb waiting to go off. Since most tanks are made of steel, infinite life is reasonably straight forward to design for. Airplanes have weight to contend with and are often made of aluminum pieces which have finite load cycles regardless of maximum stress levels seen in service. There may be other negative usage issues associated to cycling the pressure, but fatigue should not be one of them. It might be that the biggest danger point is corrosion on the welds from minerals/chemicals in the water or air.

[Tony Zaffuto]

I open the drain and let it open until the next I use the compressor.

[Chris Parks]

Mine has been "on" for ten years in this shop. I drain it once a week during late spring, summer, and early fall. Change the oil at Christmas time. I installed a street el, piece of 1/4" pipe, and a ball valve for draining.

http://i670.photobucket.com/albums/vv62/mikeinkcmo/WW%20tools/Air%20Compressor/Aircomp1.jpg


This, just make the pipe larger and the water settles in the pipe not in the tank and the tank should last longer. The bigger the pipe the less it needs draining if the user forgets. Me, I like ADV's, they save me having to access the compressor which is outside the building and a pain to get to.

[Mike Schuch]

I drain my compressor EVERY time it charges!

Well the $20 auto drain from Harbor Freight does at least. And I never worry about it.

[Ole Anderson]

I wall mounted my otherwise horizontal tank. It allowed me to slant the tank toward the drain end and to extend the drain with a 4" piece of 1/4" pipe with a ball valve at the bottom. Very easy to empty. The water gets stored in the pipe and not the tank. I empty about once a month.

[Brian Penning]

OK...another reason to drain the tank? ;)

http://www.foxnews.com/health/2011/05/25/man-turns-human-balloon-falling-air-hose/?test=faces

[Jim Davenport]

I added an extension, and ball valve. I drain the water from mine every day, when I'm done for the day in the shop. but I leave the tank pressurized
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[McKay Sleight]

My Sanborn is 30 years old and is drained whether it needs it or not every 6-12 months. Always pressurized. It's like a gun. What good is it if it isn't loaded. I think you guys are making way too much of this.

[John Coloccia]

Well, I'm pleased to report that I haven't drained the tank since I started this thread (I drained it that night, and haven't used it since so it's just sitting static). Nothing's blown up yet. LOL. Seriously, thanks everyone for all the ideas and a bit of reassurance that there's no magic to why we drain the tank. I gave it a little spritz tonight, and it's bone dry, as it should be.

Thanks!

[Karl Card]

I empty mine once a week or sooner. I have 80 gallon and I just empty it, then open the valve then turn the unit on. By turning it on, as others have said, it forces the water out and mostly never leaves any behind... then turn it off, screw the valve back and lett r rip...

[Jimmy Horrocks]

Don't you mean, tanks!!

[Neil Brooks]

And thanks from me, too.

I happened to be at the hardware store, and -- thinking of this thread -- bought the necessary hardware to run a ball valve out, at 90* from the existing valve, making it _infinitely_ easier to drain the water out of the tank if/when I think about it.

Which ... doesn't automatically change my _behavior_, but ... it DOES remove yet another obstacle ;)

[John Nesmith]

Thanks from me three. I usually drain my little 7 gal Grizzly after each use, since is often a week or more between uses. I hated getting down on my hands and knees on the concrete floor to open close the little valve. Problem now solved. (I had to raise the compressor up to make room for the installed parts I bought.)

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