Air compressor tank auto drain

[Darrell Bade]

Replacing my compressor because of a pin hole link in the tank. Many on here state using an auto drain in the tank. My Google searches have provided sketchy results, how does it work and where do I get one?

Thanks.

[Bruce Page]

I installed an IR automatic drain valve (ADV) in 2005 when I bought a new IR compressor. I can set both the cycle frequency and duration by turning 2 small knobs. I wired an on/off power switch and only cycle it when I’m working in the shop. (Our climate (NM) is relatively dry). I bought the IR ADV off of eBay in ’05 but they are available online. Installation was straight forward.

My setup: https://sawmillcreek.org/showthread.php?17659-Finally-some-air!

Some Amazon links: https://www.amazon.com/auto-drain-air-compressor/s?k=auto+drain+for+air+compressor

[Bill Dufour]

I wired mine so it only runs when the compressor motor is running. It gives a little puff on every startup and I believe it vents after every 15 consecutive minutes. I should have a push button and drain it after the tank cools.
The float type have to gravity drain from the tank into the valve body. So the tank has to be several inches off the floor.
Both types can blow the water uphill and out over 200 feet of vertical climb or more.
Bill D

[Tom M King]

I never had good luck with them lasting, and switched to using good ball valves on all of them except the one on a refrigerated dryer. I don't remember what year I bought that Speedaire refrigerated dryer off CL, but I bought the rebuild kit for it. The rebuild kit included an automatic drain, so I swapped them. That thing still works, and I've never touched it since putting it on. I do have a big industrial filter between the compressor tank and the dryer that I change the filter in every few years when I think about it, so that might matter.

[Jim Becker]

The one I had in my previous shop was an IR unit I found on sale. The one I have now was a Husky branded (and nearly identical) unit I got at the Orange Borg...on sale.

[Roger Feeley]

I got one from harbor freight at least 15 years ago and it still works (I think). I hear a little puff when it starts up and shuts down. It was a bit of a pain to install. My compressor is a 26 gallon vertical tank and the ground clearance was too tight. So I had to mess around to raise the tank.

[Cary Falk]

I installed the HF on less than a year ago. It stopped working about a month ago. I displaced one of the internal o-rings. I took it apart and fixed it but am not confident that it is going to last. It looks like they are discontinuing them.

[Darrell Bade]

Guess my Google search wasn't terrible, it brought up a lot of the electronic ones. I had not seen them before, I thought the float type was all there was. Float type makes more sense to me. The one link Bruce listed had one on that page.

[David Buchhauser]

I use a small valve like the ones used on evap cooler water lines, then just leave it cracked open a slight amount with a pan underneath. It is a very small leak, but when it gets humid any moisture in the bottom of the tank drains into the pan and evaporates. I'm not a big fan of the auto drains with timers. I like to keep it simple.

If you look closely between the legs of the belt sander you can see the drain pan (an old pie tin) next to the bottom of the compressor. My compressor came with a drain valve located at the bottom of the tank, but I removed the valve and installed a 90 degree fitting with a short length of pipe which protrudes out beyond the tank for easy access.

David

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[Tom M King]

I did the same piping the drain out to where it can easily be accessed. That's the first thing I do with one. I changed the valve to a good quality ball valve though that's easy to operate.

[Steven O Smith]

I made one using a time delay relay (mechanical) I found at the scrap yard and a solenoid valve. The relay stays on for a second (or whatever I have it set to) whenever power is applied to the motor.

[Keith Outten]

Darrell,

You had a pin hole in your tank and it didn't explode...your very lucky.

Years ago a 20 gallon air compressor blew up and totally destroyed a one car garage here in the county where I live. The owner had just left his shop and went inside for lunch. It blew all four walls out and the roof dropped straight to the ground.

Based on that accident and a few more we did a comprehensive non-destructive testing program at NASA Langley that included every high pressure vessel from huge air compressor stations and massive bottle fields to very small portable compressors. We kept very busy for several years replacing and repairing what we found from our inspection program.

I have been seriously considering purchasing an Ultrasonic Testing instrument to test my shop compressors and possibly do some free inspection for people in my area just because the danger of an exploding tank is a very serious event.

For all of you who have installed an auto-drain feature on your shop compressors, you did good!

[Jerome Stanek]

Darrell,

You had a pin hole in your tank and it didn't explode...your very lucky.

Years ago a 20 gallon air compressor blew up and totally destroyed a one car garage here in the county where I live. The owner had just left his shop and went inside for lunch. It blew all four walls out and the roof dropped straight to the ground.

Based on that accident and a few more we did a comprehensive non-destructive testing program at NASA Langley that included every high pressure vessel from huge air compressor stations and massive bottle fields to very small portable compressors. We kept very busy for several years replacing and repairing what we found from our inspection program.

I have been seriously considering purchasing an Ultrasonic Testing instrument to test my shop compressors and possibly do some free inspection for people in my area just because the danger of an exploding tank is a very serious event.

For all of you who have installed an auto-drain feature on your shop compressors, you did good!

My last compressor got a pin hole leak in the bottom and didn't blow up. Also 2 of the compressors at work got pin hole leaks and they didn't blow up

[mike calabrese]

Pin hole leaks are a result of corrosion mot likely. Corrosion in a compressor tank is dangerous. Think of it this way, it is like seeing a mouse in your house. If you see one you can bet your neck there are more. Check out compressor failures on youtube they are extremely powerful and potentially deadly.
be careful........
https://www.youtube.com/results?search_query=compressor+tank+failure
https://www.youtube.com/watch?v=W2LbTHfU5fQ
calabrese55

[Chris Parks]

A good way to minimise tank corrosion is to remove the drain valve and add a high pressure line in its place and then put the drain valve at the end of that line. set the compressor on a slight angle and the condensate should collect in the extended line instead of the tank.

[mreza Salav]

What would be a reasonable approach for someone (like me) that doesn't use the compressor frequently? Currently whenever I want to use the compressor, shut the valve and turn it on, once done for the day open the valve (at the bottom) to drain (both air and water) and leave the valve open until you want to use it next time.

[Jim Becker]

I don't use my compressor "a lot" either, Mreza, and while I turn off power to it when I'm not in the shop, I just let the auto-drain take care of blowing out any moisture. It does drain down the tank eventually, but I know it's dry.

[Bill Dufour]

I have an electric drain powered from the same switched power to the motor. It lets out a puff every time the motor starts. It puffs about every ten minutes of continuous run time. I really should add a push button switch to drain it at the end of use. It takes.a long time for a 60 gallon tank to build pressure. It holds pressure for more then one month before the gauge gets below the low pressure cut in pressure. I had to repalce the check valve into the tank wehn I bought the used tank.
Bill D

[Bruce Page]

I power off the compressor at the end of the day and usually cycle the ADV once or twice. I will cycle it the next morning when I power up the compressor again. As I said above, I live in a dry climate. If I lived in a wetter climate I would likely do things differently.

[Tom Bain]

Is there a an expected life of a compressor tank (like a pancake compressor)? In other words, after some amount of time should one just replace the whole unit (given they aren’t that expensive)?

[Mike Goetzke]

I bought a California Air compressor because of the low sound ratings. I added an auto-drain and it works great but it makes terribly loud noise when it fires.

[Malcolm McLeod]

I bought a California Air compressor because of the low sound ratings. I added an auto-drain and it works great but it makes terribly loud noise when it fires.

If the discharge port is threaded, you can get a sintered bronze muffler/silencer (<$10) that will help.

[Carl Beckett]

Is there any merit after a few years to trying to 'coat' the inside of a compressor tank to help control corrosion?

I would think all tanks corrode. Even with a water relief (given the water comes out brown...).

Hydrostatic testing is one thing but not so practical. Putting some rust prohibitor (like undercoating) I always wondered about.

[Steve Jenkins]

Is there any merit after a few years to trying to 'coat' the inside of a compressor tank to help control corrosion?

I would think all tanks corrode. Even with a water relief (given the water comes out brown...).

Hydrostatic testing is one thing but not so practical. Putting some rust prohibitor (like undercoating) I always wondered about.
I don’t know about compressor tanks but years ago for awhile they were putting an epoxy coating on the inside of steel scuba tanks. They were finding pinholes in the coating and rusting underneath.

[Carl Beckett]

yes... pretty hard to stop rust. I like the 'greasy' type of undercoats (fluid film esk) since they dont have a film to trap moisture underneath. Not sure how the vapors would be in my air line though...

My compressor head is an old one I rebuilt. It works great. But I happened upon a newer tank from a failed compressor which I swapped out just for this reason. Figured a 30/40/50 year old tank is just not worth the risk.

[Jerome Stanek]

I remember a long time ago that our fire department would buy Amway silicone and spray a couple of cans into the tanks to keep it from rusting

[Bill Dufour]

Be careful if pouring oil into a compressor tank. I bought a used tank with a comprssor that pumped oil. Replaced the pump and it's all good. The tank is coated with oil so no rust.
After I was done I realized I almost had a diesel engine explosion. I had considered adding paint thinner to help rinse out some of the oil that was flowing into the air hoses. I could smell burnt oil while using air. If I had added thinner the flash point might have dropped low enough that 125Psi would cause self ignition and blow up the tank. Acetelyne at about 30 psi will explode unless it is dissolved in acetone.
Bill D

[Jim Becker]

Don't even THINK about getting any oil in a compressor tank if one is going to use it for finishing work. Even with an oil filter, it's going to get by and make the system useless for spray finishing.

[George Yetka]

What I dont like about the autodrains is they all seam to be setup for constant run systems. I would like something that drains every 10 min of run time ideally. My home compressor isnt an issue because I can set it to work when compressor works both being 110. My work one is 3ph 208.

[Bill Dufour]

George, I wired mine up so it is powered only when the compressor motor is powered. It puffs at every startup. But, it only puffs every 10 minutes or so of continuous runtime after that. It really only time fires when I am sandblasting and the ac runs all the time to keep up.
I have no idea if they all puff when first energized.
Bill D.

[Jim Becker]

What I dont like about the autodrains is they all seam to be setup for constant run systems. I would like something that drains every 10 min of run time ideally. My home compressor isnt an issue because I can set it to work when compressor works both being 110. My work one is 3ph 208.
I agree...I've been considering putting mine on a regular timer so it's off for a lot longer time period than the 45 minute maximum native to the device.

[Bruce Page]

I added a simple power switch to my ADV to power the ADV when needed. I did not care for the automatic cycling which can be loud and startling in a small garage shop. YMMV

[Bill Dufour]

I know for AC intake they recommend a motorcycle muffler. You could add one to the drain vent hose. I added. an oil bath air cleaner to my ac intake. I figure it quiets the intake and oils the valves.
I drilled a hole through an outside wall and vent the auto drain under a tree.
Bill D

[Malcolm McLeod]

I added a simple power switch to my ADV to power the ADV when needed. I did not care for the automatic cycling which can be loud and startling in a small garage shop. YMMV

You can also power the ADV off of the shop's lighting circuit. It won't bleed down when you're not there.

Another option is to power the ADV off the switched side of the AC motor power. This requires some wiring surgery, but cycling quits when the motor stops; likely you will only 'vent' once per pressure cycle in typical hobby usage.

See sintered bronze filter/muffler for noise.

[Patrick McCarthy]

I bought a California Air compressor because of the low sound ratings. I added an auto-drain and it works great but it makes terribly loud noise when it fires.

Mike, mine had a shot like sound when at the factory default setting of 0.5 second, but when i moved it to approx 1 1/2 seconds i now get just a psssstt sound; much less startling.

[Patrick McCarthy]

I added a simple power switch to my ADV to power the ADV when needed. I did not care for the automatic cycling which can be loud and startling in a small garage shop. YMMV

Bruce, what type of power switch? Is it like surge protector strip that you can just turn off? Or it a different set-up?

BTW, i copied your brilliant idea of running the discharge drain tube into a 5 gal container, but did low tech zip ties to keep the hose from whipping out with each discharge. Yours is much more elegant.

Thank you, Patrick

[Bruce Page]

Thanks Patrick. The switch is just a simple lighted rocker switch.

[David Dille]

This is a puzzler to me. I had a 20 gallon Cambell-Hasfield for nearly 30 years. Would drain it about once per year. Mostly just a very tiny bit of moisture. Sold it 6 years ago but I know the guy. So this almost 40 year old compressor is still working fine without being drained constantly. My current compressor is a 30 gal oil. The drain plug for it, is not on the absolute bottom so I can’t drain it completely. When I do pop the cock, all I get is a tiny, tiny bit of oily mist. When I was young, about a thousand years ago, I worked in a Cat shop. We had several huge compressors. One was a 12.5 hp, the other a 10 hp. Huge tanks. I asked the head mechanic about draining them and he just laughed and said sure, if you can get to the drain, go for it. Well, I couldn’t get to the drains.

I did seismic drilling up on the North Slope of the Brooks Range in the very early 80’s and one year, we used what they call mud guns out on the ice of the Beaufort Sea. Seven stage compressors with a 7500 psi charge. I could see those taking out a house but it’s hard to believe a tiny shop compressor, maybe 20 gal, 2 hp, could rupture a tank enough to take out garage walls, just not enough volume, but hey, what do I know.

Anyway, I just don’t think it’s a huge deal. Again, totally unsupported opinion. Just based on my own 50 years of experience but certainly, err on the side of caution. 😀

[Jimmy Harris]

What would be a reasonable approach for someone (like me) that doesn't use the compressor frequently? Currently whenever I want to use the compressor, shut the valve and turn it on, once done for the day open the valve (at the bottom) to drain (both air and water) and leave the valve open until you want to use it next time.
Keep doing what you're doing. That's why I've always done, and pretty much everyone I know who owns a compressor outside of a commercial setting. It works fine if you're not using the compressor often. It's how they are designed to operate.

I've had several jobs where compressors ran at least 8 hours a day, five days a week, and often more. They need those automatic release valves. They cycle literally tons of air a day. So they'll build up lots of water without them. They have a near constant drain on the tank. And when the automatic valves do go off, they leave enough water to pool up on the floor. That's enough to rust a tank. On my home compressor, there might be enough water that you can feel the spray is wet when you empty the tank. But it doesn't make a pool of water below it. It just doesn't cycle enough air under my normal use to be a concern.