Off Topic: Air Compressor Question

[XX Case XX]

I just got through using my air compressor. When I opened the valve at the bottom to let all the air out, I could feel moisture in that air. So here's my question: When I'm through using the compressor and I open the valve to let out all the excess air, should I close that valve or leave it in the open position?

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Mike

[Montanaman]

I just got through using my air compressor. When I opened the valve at the bottom to let all the air out, I could feel moisture in that air. So here's my question: When I'm through using the compressor and I open the valve to let out all the excess air, should I close that valve or leave it in the open position?

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Mike

For me , it would depend on how big the tank is and how much humidity? air line dryer? For a busy shop with a big tank in a humid environment, it would be best to drain it every night. For an at home guy with a small tank, just letting the water out should be fine. I have a big tank in a low humidity environment, so I only drain the water out every few months. I would recommend an inline dryer/oiler if you have a lot of moisture in the line, moisture is hard on air tools.

[ea42]

Mike if it's a small compressor I don't think there's a need to leave it open, most of the moisture should have been forced out through air pressure. I have a small pancake compressor that I ran for ten years on construction and been running an additional five years in my shop. If I run it all day I drain it at the end of the day. In the construction days there's actually be a stream of water running away from the compressor. If I use it sporadically I'll drain it after every three or four days of use. Haven't had any problems doing it this way. Knowing me, if left it open I'd forget by the next time I turn I on. Then after an hour of running continuously I'd be wondering why the thing's not coming up to pressure LOL!

As Montanaman said in-line dryers are a big help if you run it continuously in a shop.

Eric

[zzyzzogeton]

How often you need to drain a compressor depends on 2 things - how much it is run and how humid are your environmental conditions.

Out in the deserts of Arizona or west Texas, you could generally run a big shop compressor without in-line dryers literally for days. If there is little moisture in the air, there is littl to condense out.

In humid areas, such as Houston, I know of shops that run their compressors all day 5 or 6 days a week with in-line dryers who still need to drain their tanks at the end of the day.

I have a couple of small compressors (5 gal pancake and 20 gal tank) here in central Texas. I only have to drain them about 1x per month, and that's mainly as a precaution. I could probably go 2 months during the drier times of the year.

[XX Case XX]

Thanks for the information fellas. I use it for about 10 minutes every 5 or 6 months when I check the tire pressure on the cars. Other than that it just sits there. California is pretty dry so there's not a lot of humidity. Here's some pictures.

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Mike

[fergusontd]

I drain mine after every time I use it. 26 gal. Craftsman upright compressor, I've had it since '95. ftd

[kootenay joe]

Why is it that you should not run your compressor using an extension cord ? I assume you can if gauge of extension is correct for it's length but i don't understand why this is needed.
kj

[rexstubbins]

Close it is the simple answer.

Explanation is - if you leave it open in a humid environment then moisture will get in more so than if you closed it because the closed valve and the closed piston will keep the moist air out.

If it's a dry environment then it might dry out the inside of the tank if you leave it open.

The moral is it probably does not matter at all if you leave it open or closed after draining but if you don't drain it at all then there is a huge problem because the compression of air creating the water will leave a huge pool of water within the tank and rust out the tank.

Having said that - I'm almost always completely wrong about stuff like this.

[Mumbleypeg]

If your compressor has a drain, it is there for a reason. It needs to be drained. How often depends mostly on how much it is used. I have a 30 gallon compressor in the shop, but it doesn’t run every day. I turn it on when I need it, and then turn it off when I’m not in the shop. The tank is usually at around 125 lbs when I shut it off and it will hold that pressure. I used to leave it on all the time. I drain it about once every two or three months.

As for the extension cord question: an electric compressor motor pulls a lot of current, especially during start up. I’m no electrician but I know enough to know the longer the cord is and the smaller the gauge of the wire, the less current is delivered at the point of use. Sorta like water pressure - the longer your hose and the smaller the diameter, the lower the pressure will be at the nozzle. So if your application requires a lot of juice/pressure, you want the cord/hose to be large diameter and as near the source as possible. When you buy a compressor it comes with a cord that has been designed to have the right wire gauge for the amps pulled by the motor.

An extension cord wire probably isn’t the same gauge - it’s likely too small. It won’t deliver sufficient amperage to efficiently (quickly) start the electric motor. It may start, but in doing so it will probably damage the start mechanism (due to overheating).

That’s my theory anyway.

Ken

[zoogirl]

I don’t handle the big compressor, but when we use the machine that forced leges into plastic drakes, I always drain it’s tank and then close it. Coastal BC is pretty humid.
In the summer, we often get water in the hoses and just stick a blower nozzle on the hose and blow until it clears.
Both my drill and my riveter, as well as the nail gun, are all air.

[kootenay joe]

Thanks Ken, What i don't understand is why the electric motor on a compressor needs so much more current than other electric motors, e.g. electric lawnmowers run on a long fairly light weight extension cord. Yet even a small compressor should not be used with an extension cord, or if you do it has to be short and big gauge wire.
kj

[FRJ]

I never drain mine ............ Until just a little while ago.

I used mine for several years for trim carpentry and usually drained it.
After I kept it in my shop, with much less work, for several more years I just forgot about it.

[Mumbleypeg]

I never drain mine ............ Until just a little while ago.

I used mine for several years for trim carpentry and usually drained it.
After I kept it in my shop, with much less work, for several more years I just forgot about it.

That’s a great example of why you should drain it. If not drained, the moisture inside will accumulate and eventually rust the inside of the tank. Which will in turn weaken it and eventually cause it to fail. Plus the water displaces area which could otherwise be holding air.

Roland, I think it is related to the amount of amps required to perform the work being done. Compressing air is not easy work - apparently more work than cutting grass. A compressor operates by sucking in air on one stroke of its piston, and compressing it to 125+ pounds and pushing it into the storage tank on the opposite stroke. As the amount of air (and pressure) inside the tank increases, the effort required to push air into the tank is progressively increased, up to the desired pressure of the stored air. The electric motor running a compressor typically requires a large motor start capacitor to boost the energy to start it.

By comparison a lawn mower has a relatively stable work load, therefore a relatively smaller electric motor. It is turning a blade, not a compressor piston or pistons (depending on whether it’s a single-stage or dual stage compressor).

Again, that’s my theory anyway. Maybe a real mechanical engineer will see this and enlighten us.

Ken.

[Old Folder]

Great OP Mike (xx Case xx)
I normally open my drain valve after every use, but I was not totally sure if it is required. So....I dug out my "Operators Manual" to research the proper procedure.
(I have posted pictures below of the Maintenance and Storage pages from the original manual.)
I purchased this 30 Gallon 6 HP beast in 2001 from Sears. It is a bit overkill for my every day Air Compressor needs but comes in handy for my nail and staple use pertaining to my woodwork hobbies. In 2001 there was not as many Compressor options as there are now. I would now purchase a much smaller unit.
It remains in my garage during activation and use. I must inform my wife before I activate it due to its extremely high Decibels and reassure her that I did not purchase a RF4 Phantom Jet Fighter. I must use noise-cancelling headphones when I activate the on switch.
If you take it outside an enclosed garage for activation, the noise reciprocates to a tolerant noise level. However, if I took it outside the garage it would require an extension cord no longer than 50 feet in length with a 12 gauge (AWG) or larger. (Wire size increases as gauge number decreases) The manual states: "DO NOT USE 14 OR 16 AWG."
Fortunately, I have a #12 gauge GFCI 20 AMP outlet leading into my garage. I use a 50 foot recoil extension air hose (Pictured below) instead of an extension electrical cord. The hose is 3/8" diameter with common 1/4" NPT fittings. Therefore I do not have to roll this monster machine around to accommodate its use.
You will also notice the small red tubed bowl at the end of the air hose connector, this is an aftermarket "Moisture Absorb-er" add-on I attached to filter out airline moisture and to assist in keeping my air powered tool mechanisms dry.
So, yes! our Air Compressors should be air drained after every use.

[Old Folder]

I thought I would add: "If you need an Air Compressor for light duty compression such as Tires, pool toys, sports equipment etc. I suggest the below "Goodyear" unit. I have had it for over a year now, available from Amazon. It will not break the bank and I am very happy with it. I do not need ear muffs nor do I have to inform the boss when I activate is."

[kootenay joe]

With the small 'compressor' as there is no tank, i think it would not work for cleaning purposes, like blowing dirt out of a tool.
Is this correct ?
kj

[orvet]

You will also notice the small red tubed bowl at the end of the air hose connector, this is an aftermarket "Moisture Absorb-er" add-on I attached to filter out airline moisture and to assist in keeping my air powered tool mechanisms dry.
So, yes! our Air Compressors should be air drained after every use.

Dan,
if you are getting moisture and in your air tools & paint guns in spite of your moisture trap you might try moving the trap off of your compressor, mounting it somewhere else and run about 25 feet of air hose to the moisture trap and then run the hose from the trap to your tools.
The reason for that is; the air is heated when it is compressed & hot air can carry more moisture than cold air.

The 25 feet of air hose even if it’s just coiled up on the floor between the compressor and the moisture trap gives the air time to cool off considerably and increases the effectiveness of the moisture trap dramatically.
If you’re in a drier climate that may not be necessary, but if you find your air tools are spitting a mist of condensation, or you are finding water droplets in the paint when spray painting, then an extra 25 to 50 feet of hose can make a big difference in the effectiveness of your moisture trap.

[Old Folder]

You will also notice the small red tubed bowl at the end of the air hose connector, this is an aftermarket "Moisture Absorb-er" add-on I attached to filter out airline moisture and to assist in keeping my air powered tool mechanisms dry.
So, yes! our Air Compressors should be air drained after every use.

Dan,
if you are getting moisture and in your air tools & paint guns in spite of your moisture trap you might try moving the trap off of your compressor, mounting it somewhere else and run about 25 feet of air hose to the moisture trap and then run the hose from the trap to your tools.
The reason for that is; the air is heated when it is compressed & hot air can carry more moisture than cold air.

The 25 feet of air hose even if it’s just coiled up on the floor between the compressor and the moisture trap gives the air time to cool off considerably and increases the effectiveness of the moisture trap dramatically.
If you’re in a drier climate that may not be necessary, but if you find your air tools are spitting a mist of condensation, or you are finding water droplets in the paint when spray painting, then an extra 25 to 50 feet of hose can make a big difference in the effectiveness of your moisture trap.

Thank you for the great advise Dale
That makes a lot of sense, I will adjust the moisture trap accordingly.
My above post duplicated the Air Compressor picture , it should have shown the added hose below.

[Old Folder]

With the small 'compressor' as there is no tank, i think it would not work for cleaning purposes, like blowing dirt out of a tool.
Is this correct ?
kj

You are correct kj, the small compressor I posted above would be of no help to eliminate moisture as in cleaning.

[mrwatch]

in the 1960's - 1980 my dad had a large gas station with two lifts. The air hose outside was more like a water hose with a nozzle instead of a tire inflator. Could drain into a bucket. I once bought a smaller used air compressor at a garage sale with out trying it first. As said= rusted thru under the top unit. $5 wasted and now have the motor and pump parts.

[XX Case XX]

You will also notice the small red tubed bowl at the end of the air hose connector, this is an aftermarket "Moisture Absorb-er" add-on I attached to filter out airline moisture and to assist in keeping my air powered tool mechanisms dry.

I've never seen one of those. Maybe they have one for my compressor too. I will definitely look into that. Thanks!!! And thank you for posting the instructions as well. That's good information to know.

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Mike

[XX Case XX]

I thought I would add: "If you need an Air Compressor for light duty compression such as Tires, pool toys, sports equipment etc. I suggest the below "Goodyear" unit. I have had it for over a year now, available from Amazon. It will not break the bank and I am very happy with it. I do not need ear muffs nor do I have to inform the boss when I activate is."
IMG_0003.JPGIMG_0004.JPG

Thank you for that information. I was thinking about getting another smaller unit and that might do the trick. Many thanks!!!

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Mike