Compressors

Hi,

I am new to compressors and would like to know the best way to use one. I have a 6 gallon electric pancake unit. The manual says that when idle I should shut it off and let out the air so condensation doesn't build up in the tank. I wasn't expecting that. Is that really necessary? I'll only really be using the unit on weekends. Mostly to run my bike lift table and air in the tires. Etc. All light duty general stuff. Can I leave it on all weekend, and just let the air out at the end of the weekend?

Doug

Hi,

...Can I leave it on all weekend, and just let the air out at the end of the weekend?

 

Doug

That's the way I always intend to use mine. Then I hear it running Tuesday midnight after I'm in bed and trudge out to the garage in my bare feet to turn it off.

Better to turn it off when you quit working.

I see you're in Texas. The dry side, or the humid side?

I have several compressors at work. They run 24/7 (or I guess I should say the air is in use 24/7). Yes, they do fill up with water. For instance I empty one about once a week. There's maybe 1/2 gallon in there, in a 20 gallon tank. It all depends on your ambient humidity, the on-time, and perhaps some other factors. It doesn't matter if it's warm or cold out.

If you're just using it occasionally on weekends here and there, you could probably ignore it. Of course, yes, the best procedure would be to shut it off and drain the tank, especially if you're looking at long term storage. But I've seen a lot of compressors with remarkable amounts of water in them, and the owners don't seem to know or care. Besides the tank rusting, a significant amount of water reduces the useful size of the tank. Eventually it will lower your CFM, increase the on time of the motor, and lead to premature failure.

Use it for a day, open the drain, see how much moisture you get, if any. With small amounts of use, in a dry climate, you'll just get damp air. Wait progressively longer periods between draining it, and then do what you think is right. You probably have a limit as to how much effort you want go to, for a thimbleful of water. But yes, you can leave it on all weekend, all week or all month. And you can leave compressed air in the unit. Just keep in mind that there is probably a little water in there too, and there's nothing reasonable that you can do to prevent it. Really, the moisture problem becomes significant when your humidity is high, and you have constant usage or leaking. Then the compressor cycles on and off, and continues to put more moisture in the tank. And then you end up with a 1/2 gallon in there like me....

Another thing that can be done (and perhaps is something I should be doing) is crack that drain valve ever so slightly so it's always pushing water out the bottom of the tank. The trouble with that, though, is that you start thinking you can ignore it, and before long a speck of rust clogs the valve, and you're back where you started, only it's been 2 months since you thought about it.

Hope that helps.

Dougs location of Flour Mound - near Dallas Fort Worth....less humid than the swamp of Houston I live it where moisture is a big problem with everything. Doug.......I have a standup compressor and a small portable. They get water from the air. Water rusts tanks. Rusted tanks can do bad things given enough time, enough rust, and enough pressure. My tanks are for my hobbies not used professionally. When I know I'm done with them for a couple of days or longer, I let the air out, and open the water drain at the bottom. There is always some water after a day or two of usage. Once a year or so, I take the valves off and inspect them visually for rust. I just recently threw away a 30 gallon unit that had some rust. I had the unit for about 25 years and for precaution, I thought it had served enough cycles.

I shut mine off & bleed the tank after each use. That way I don't have to listen to periodic recharging of the tank at all hours.

You'll notice some moisture leaking from the tank release valve every time you engage it, confirming moisture does indeed collect in the tank.

Really no right or wrong here, just personal preference.

......

 

I have several compressors at work. They run 24/7 (or I guess I should say the air is in use 24/7). Yes, they do fill up with water. For instance I empty one about once a week. There's maybe 1/2 gallon in there, in a 20 gallon tank. It all depends on your ambient humidity, the on-time, and perhaps some other factors. It doesn't matter if it's warm or cold out.

I suggest the installation of an electronic auto drain valve (solenoid type with a strainer) but still check it occasionally.

Besides the tank rusting, a significant amount of water reduces the useful size of the tank. Eventually it will lower your CFM, increase the on time of the motor, and lead to premature failure.

Yes water will reduce the storage volume so the on/off cycles will be Reduced in proportion to the amount of accumulated water (water doesn't compress).

 

I shut mine off & bleed the tank after each use. That way I don't have to listen to periodic recharging of the tank at all hours.

 

You'll notice some moisture leaking from the tank release valve every time you engage it, confirming moisture does indeed collect in the tank.

 

Really no right or wrong here, just personal preference.

I have had mine for about 30 years or more. I got it to paint a car, now it is just handy for tires and blowing things clean. I do the same: shut it off and open the drain on the tank after every use. Sometimes I let is sit for awhile before opening the drain valve. I don't like to listen to the loud sound of air coming out the valve when the tank is fully pressurized.

Hi,

I am new to compressors and would like to know the best way to use one. I have a 6 gallon electric pancake unit. The manual says that when idle I should shut it off and let out the air so condensation doesn't build up in the tank. I wasn't expecting that. Is that really necessary? I'll only really be using the unit on weekends. Mostly to run my bike lift table and air in the tires. Etc. All light duty general stuff. Can I leave it on all weekend, and just let the air out at the end of the weekend?

 

Doug

Morning Doug

My compressor is just a bit bigger, 120 gallon with a 4 cylinder pump so it makes big water (especially in damp weather) so I need to drain it often. I just drain the water from the bottom

drain but don't release the air in the tank (ever). I also have a large air drier/water separator on the compressor outlet to cool & dry the outlet air

The compressor is on most of the time I am home or working but I do turn it off when I leave my shop overnight or traveling. If it blows a line off or pops a hose (I run 175 psi shop pressure) I don't want it running continuously until I return.

If your compressor has a moisture drain on the bottom then no real need to drain the air out every night (just drain the moisture out the bottom after the air in the compressor cools & the water condenses & falls to the bottom of the tank). You can leave the tank charged with air all weekend if using the compressor next day or so but should drain it the release the air when storing it or if it will sit for weeks.

Those little pancake compressors make a lot of heat in compressing the air so do make a lot of water while compressing/heating the air so should be drained often. You should also run some sort of water separator so you don't run a lot of moisture through your lift cylinder or air tools as that will eventually corrode them up inside.

Maybe think of getting a second (non compressor) air storage tank then charge that before you shut your compressor down. That way you will always have a shot of air handy to run a blow gun or fill a tire without having to run your compressor then re-store it.

I've had my 33 gallon Sears Craftsman compressor for 11 years. I use it and just turn the power off so it doesn't cycle. I've never drained the tank and all my air tools work accordingly. Just my experience.

I have 3 compressors, 2,6 and 33 gal. All are the oil less type which is fine for hobby and moderate use. Commercial grade units typically have oiled compressors which need their oil changed. While I do not drain the air off after each use I do turn the unit off or unplug it when not actively using. I do drain off the moisture at least every month. And weekly if I am using it daily. Less so in the ultra dry winter. You should do it at least weekly until you get a sense of how mush moisture accumulates in the tank and adjust freaquency as needed. I do use a moisture separator on the 33 gallon unit to keep water out of my pneumatic tools and drain that whenever I see water in it and if the separator accumulates a good amount of water when using the compressor I will drain the main tank as well.

Since you are in Texas you likely will not have the below freezing caution. In any case you can always assume there is some moisture in the compressor and if frozen could damage it if you try to run a frozen unit. For winter use I bring my 6 gallon unit that is kept in a unheated pole barn into a warm space overnight before use.

...

 

Besides the tank rusting, a significant amount of water reduces the useful size of the tank. Eventually it will lower your CFM, increase the on time of the motor, and lead to premature failure.

Yes water will reduce the storage volume so the on/off cycles will be Reduced in proportion to the amount of accumulated water (water doesn't compress).

 

Yeah, I kinda glossed over how that works. With large proportions of water, you effectively wind up with a small tank. Individual on cycles are shorter, but the unit runs more often to push the same volume of air. In extreme situations, it'll practically be on all the time. But I realize now, that I'm assuming that the thing is connected to some equipment that consumes air 24/7 (that's what I see most often). Perhaps that's not a good example for this discussion.

 

Living the Dream,

You might be surprised at the amount of water your Craftsman compressor is making and storing for you.

I have owned and operated more than two dozen air compressors, both at home and at work, single stage, handheld, to two-stage vertical 50 gal 220V shop compressors. They ALL "make water". It's nothing personal, it's physics, very similar to the "refrigeration cycle" that makes your AC's work. The problem with the water, as others have said, is that it keeps accumulating and it will rust steel.

The best solution I've found is to have a VERY EASILY ACCESSIBLE and EASY TO OPERATE drain valve, like a 1/4 turn, 1/4 inch brass ball valve with a discharge to a drain or outside. I have yet to see a production compressor/storage tank with one of these, even the better "industrial" compressors.

Thanks everyone. I can always get the information that I need on this site.

Living the Dream,

 

You might be surprised at the amount of water your Craftsman compressor is making and storing for you.

 

I have owned and operated more than two dozen air compressors, both at home and at work, single stage, handheld, to two-stage vertical 50 gal 220V shop compressors. They ALL "make water". It's nothing personal, it's physics, very similar to the "refrigeration cycle" that makes your AC's work. The problem with the water, as others have said, is that it keeps accumulating and it will rust steel.

 

The best solution I've found is to have a VERY EASILY ACCESSIBLE and EASY TO OPERATE drain valve, like a 1/4 turn, 1/4 inch brass ball valve with a discharge to a drain or outside. I have yet to see a production compressor/storage tank with one of these, even the better "industrial" compressors.

 

Might be so, but all is well after the 11 years I've had it and if it rusts through,...I've got my money's worth.

I've always thought the tanks should have an interior plastic coating, at least on the bottom half. Wonder if a gas tank sealer like Kreem or POR 15 could work...

I've always thought the tanks should have an interior plastic coating, at least on the bottom half. Wonder if a gas tank sealer like Kreem or POR 15 could work...

Afternoon Larry

I don't know about POR 15 but Kreem is probably not a good choice as that stuff can flake off in sheets & chunks. Not a big deal if an inline filter or separator is used to protect air guns & air equipment but it is a very BIG deal if a piece would break loose & plug off the pressure control switch or plug the overpressure blow-off valve.

Kind of like oil threads. Lots of different opinions from drain often to "don't worry, be happy".

I had a dewalt 6 gallon tank on wheels. When the pressure regulator switch bit the dust. I decided I had received full value and bought a new one.

YMWV

I've always thought the tanks should have an interior plastic coating, at least on the bottom half. Wonder if a gas tank sealer like Kreem or POR 15 could work...

The problem with an interior coating here (actually, ANY coating) is the SURFACE PREP. You would need an SSPC Near White sandblasted surface, about 95-98% of the rust removed and the surface profiled for paint/epoxy bonding. You really can't do that in a small tank. That's why the coatings come off "... in sheets & chunks." as Dirt Rider said above.

Just doing the bottom half will not accomplish much as the condensation forms on ALL the inside surfaces. Pre-coating the inside wouldn't work because welding the seams would burn off any coating and would then need to be re-blasted and coated themselves. The cost would be prohibitive anyway. Usually, the pump fails several times before the tank rusts thru and the entire thing is tossed for a shiny new one.

If you want a small A/C, get a SENCO PC1010 on Amazon for $104. These are very durable, very quiet, all parts are on Amazon, commercial grade compressors. I found one on craigslist for $40. Stay away from DeWalt compressors.

 

I shut mine off & bleed the tank after each use. That way I don't have to listen to periodic recharging of the tank at all hours.

 

You'll notice some moisture leaking from the tank release valve every time you engage it, confirming moisture does indeed collect in the tank.

 

Really no right or wrong here, just personal preference.

Ditto! This is how I have used mine for the past 15 years with zero issues.

I have 2 compressors I use somewhat regularly......a 33 gallon craftsman, and a 2.5 gallon Dewalt cordless compressor. The Dewalt always get its valve flipped open to let the air out when I'm done with it. When I need it, it pumps back up quickly enough that there is no down time waiting for it, so why not? With the larger 33 Gallon, I decided last summer that I should probably empty the "water" from the tank.....its ~13 years old and had never had the tank bled for any reason. I always shut it off when done as it is in the garage right under our bedroom, but never let the air out. So, I drug it outside, bled all the air out, unscrewed the drain, and proceeded to get about 6 drips of water out of it. I'm never doing that again.

Keith,

I guess being next to a giant lake would make for more humidity here, but that little moisture coming out after 13 years is almost too weird. I would get that amount in a day of use. And you don't hear water sloshing in the tank as you move the compressor around

Keith,

 

I guess being next to a giant lake would make for more humidity here, but that little moisture coming out after 13 years is almost too weird. I would get that amount in a day of use. And you don't hear water sloshing in the tank as you move the compressor around

No argument from me. I had talked to a buddy that claimed he had almost 1/2 of his 50 gallon tank filled with water. So much so that he couldn't move it and had to drain the water into a catch pan and manually carry it outside. I was expecting the worst. I got so little out, that if I would have had a wash cloth under the compressor, I wouldn't have been able to wring it out when I was done. Beats me.....our humidity fluctuates through the seasons here, but its not like its the Sahara

I've always thought the tanks should have an interior plastic coating, at least on the bottom half. Wonder if a gas tank sealer like Kreem or POR 15 could work...

 

 

The problem with an interior coating here (actually, ANY coating) is the SURFACE PREP. You would need an SSPC Near White sandblasted surface, about 95-98% of the rust removed and the surface profiled for paint/epoxy bonding. You really can't do that in a small tank. That's why the coatings come off "... in sheets & chunks." as Dirt Rider said above.

 

Just doing the bottom half will not accomplish much as the condensation forms on ALL the inside surfaces. Pre-coating the inside wouldn't work because welding the seams would burn off any coating and would then need to be re-blasted and coated themselves. The cost would be prohibitive anyway. Usually, the pump fails several times before the tank rusts thru and the entire thing is tossed for a shiny new one.

 

If you want a small A/C, get a SENCO PC1010 on Amazon for $104. These are very durable, very quiet, all parts are on Amazon, commercial grade compressors. I found one on craigslist for $40. Stay away from DeWalt compressors.

 

Plus one on the Senco. Good unit , great price, quiet to boot

Check out this review of a super quite small compressor

Compressor Review

 

No argument from me. I had talked to a buddy that claimed he had almost 1/2 of his 50 gallon tank filled with water. So much so that he couldn't move it and had to drain the water into a catch pan and manually carry it outside. I was expecting the worst. I got so little out, that if I would have had a wash cloth under the compressor, I wouldn't have been able to wring it out when I was done. Beats me.....our humidity fluctuates through the seasons here, but its not like its the Sahara

Evening OoPEZoO

It depends on the relative humidity of the intake air & how much pressure that you are running. (how much you reduce air volume)

At 10-15% relative humidity & only compressing to 100-125 psi then you probably won't be compressing the air to reach 100% humidity therefore the water doesn't fall out of the compressed air inside the storage tank.

At 50% or higher relative humidity and/or compressing the air to higher PSI then the air volume decreases under pressure but the moisture in the air doesn't so it easily reaches 100% humidity & the water drops out into the tank.

I run 175psi in my system so it makes lots of water even at moderate to low humidity intake air.

Evening OoPEZoO

 

It depends on the relative humidity of the intake air & how much pressure that you are running. (how much you reduce air volume)

 

At 10-15% relative humidity & only compressing to 100-125 psi then you probably won't be compressing the air to reach 100% humidity therefore the water doesn't fall out of the compressed air inside the storage tank.

 

At 50% or higher relative humidity and/or compressing the air to higher PSI then the air volume decreases under pressure but the moisture in the air doesn't so it easily reaches 100% humidity & the water drops out into the tank.

 

I run 175psi in my system so it makes lots of water even at moderate to low humidity intake air.

 

 

I used to get water in mine when it was new and I lived in San Francisco. Since then I moved first to Colorado and now to Guadalajara. I never see any water come out the drain. I think it is a combination of: lower pressure that it runs at now and the drier air in Colorado and Mexico, as DirtRider points out.

I don't close my drain valve tightly. Water just dribbles out and it doesn't affect the number of restarts. My compressor is on 24/7 and starts about 2 or 3 times in 24 hours...

If you already have a compressor and it isn't big enough to seat the beads on your rims, or you need a portable air supply to walk around and air-up tires with, this might be just the thing, $60:

5 and 10 gal air tanks on Amazon