Air compressor in garage attic - Not your typical compressor thread

tig · Feb 10, 2011

I've really tried to read through all the air compressor threads before posting this. I do not want to start yet-another-air-compressor-thread, but I don't think I have a choice.

I currently have a cheapo Craftsman portable compressor that is inadequate for my needs. I am going to pull the trigger on a new compressor in the next week.

Requirements:

Will be installed in the attic of my garage. Attic is insulated and will significantly mute sound. It has a vent to the outside which is right near where the compressor will go.
I had the garage plumbed for air when it when built. Copper pipe has been installed to location in attic. It runs down to 4 locations below.
I have had a 220v circuit (single phase) wired to the location in the attic.
Attic is only about 5'4" high (!).
Besides standard air hand tools such as impact wrenches, I will use the air for an air powered scissor jack, die grinder, and (someday) a blast cabinet.
This is not a commercial situation and my usage is relatively infrequent and irregular (I guess on average I use my current compressor once a month; this will increase, but not significantly).
Being the attic, fairly inaccessible, I require reliabilty and limited regular maintenence.
I don't want to spend more than $2000. I'd rather spend far less.

Looks like horizontal tank compressors are significantly rarer and more expensive than vertical. Why is this?

What should I be thinking about regarding ongoing maintenance?

Anything regarding dealing with condensation beyond good filters? FWIW, the photo below shows the copper lines going down from the attic...

tig · Feb 10, 2011

One more question:

Norhtern Tool lists two categories of compressors: Reciprocating Air Compressors and Electric Powered Air Compressors. What's the difference?

1931S/X · Feb 10, 2011

i had the same plans but my garage has a hip roof and i would only be ably to put my big compressor right in the center. i didnt hook up the big one yet but i have my small compressor up there and i like it. i have a 50' hose coiled up into one down pipe with a trap on the bottom and a regulator and seperator. my air is pretty dry.

Addrock · Feb 10, 2011

I like the thinking ahead! I would plumb in an automatic drain, and run a line to the heated space and out or to the drain ideally. If the attic vent faces a neighbor or even a loved one of the female persuasion I might still box it and have garage air as the air in (out to the attic). This would also be my suggestion if you live in a cold climate. I built an enclosure like this for soundproofing in a shop the improvement was -50db.

Addrock · Feb 10, 2011

I've been thinking about buying a big tank and putting it into my knee wall.

pipsters · Feb 10, 2011

I saw a local craigslist offer for a Rol-Air (I believe is how you write it) 30 gallon horizontal that did 17 CFM @ 100 psi for $300. That is better than most of the uprights. If you needed more air you could always plumb in another 30 gallon tank or something. It was a 220V unit. Maybe look for something similar.

sfckiddo · Feb 10, 2011

you have to periodically drain the tank of water or it will rust from the inside. have you thought of the wieght of a bigger unit? i have mine outside under a small leanto on the back side of my shop.

impulse922 · Feb 10, 2011

Eaton makes a 80 gal/5hp for $1400 + freight. It is available with a horizontal tank. Next best thing would be a Quincy.

http://www.eatoncompressor.com/catalog/item/504747/206953.htm

tig · Feb 10, 2011

impulse922 said:
Eaton makes a 80 gal/5hp for $1400 + freight. It is available with a horizontal tank. Next best thing would be a Quincy.

http://www.eatoncompressor.com/catalog/item/504747/206953.htm

Looks good. Any commentary on Eaton quality?

tig · Feb 10, 2011

sfckiddo said:
you have to periodically drain the tank of water or it will rust from the inside. have you thought of the wieght of a bigger unit? i have mine outside under a small leanto on the back side of my shop.

Looks like many compressors now include automatic drain systems (like the Eaton linked to above).

When we built the garage we anticipated the compressor going there and so the framing was re-enforced. Getting it UP there will be tricky, but not insurmountable.

larry_g · Feb 11, 2011

tig said:
Looks good. Any commentary on Eaton quality?

Search around her for eaton, I seem to remember a thread about Eaton and it was not good. It may have been another brand. Seems to to me it was in the last few weeks. Link in this thread; http://www.garagejournal.com/forum/showthread.php?t=88404&highlight=eaton

lg
no neat sig line

scott37300 · Feb 11, 2011

pipsters said:
I saw a local craigslist offer for a Rol-Air (I believe is how you write it) 30 gallon horizontal that did 17 CFM @ 100 psi for $300. That is better than most of the uprights. If you needed more air you could always plumb in another 30 gallon tank or something. It was a 220V unit. Maybe look for something similar.

Sounds like the same compressor I have. That's a great deal considering they are almost 1500 new and made in USA.

GeorgiaHybrid · Feb 11, 2011

If you can find a used Quincy, Champion, etc that is mounted on a vertical tank, you can always sell the tank and buy a new, horizontal, ASME tank to put the compressor on. I have a local company that will sell a 60 gallon horizontal tank with a std mounting plate for $344, an 80 gallon for $419 and a 120 gallon for $610.

pipsters · Feb 11, 2011

scott37300 said:
Sounds like the same compressor I have. That's a great deal considering they are almost 1500 new and made in USA.

Damn I knew I should've bought it. I did see the "Made in USA" on the placard in the picture. It was a 2 hour drive and I was feeling lazy, plus I really couldn't justify buying it as it would be mothballed for a while as I'm not going to put 220 in my current garage.

Specs looked good, seemed like a really powerful compressor and a good compact size.

scott37300 · Feb 11, 2011

pipsters said:
Damn I knew I should've bought it. I did see the "Made in USA" on the placard in the picture. It was a 2 hour drive and I was feeling lazy, plus I really couldn't justify buying it as it would be mothballed for a while as I'm not going to put 220 in my current garage.

Specs looked good, seemed like a really powerful compressor and a good compact size.

It is a great compressor, they don't get mentioned as much as some big names but they are a solid two stage compressor. The smaller ones are a standard in the construction industry around me. I bought mine used and it sat for almost five years till I got it set up. For the price you listed I would pick it up and store it till ready to use.

tig · Feb 11, 2011

How do you folks think this SnapOn unit would meet my requirements (assume I can get it slightly used/cheap). The only downside i see is the relatively smallish 40 gallon tank; but for my infrequent use I doubt that will be a problem.

http://buy1.snapon.com/catalog/item.asp?store=snapon-store&item_ID=77751&group_ID=13098

Stock # BRA5140H
Name Air Compressor, Stationary, 40 gallon, 5.0 HP, 175 max. PSI
Price** $2,443.85
Brand Snap-on
Country Of Origin Canada
Horsepower, HP 5
Pump Stages Dual
Tank, gal. 40
Tank Style Horizontal
Electrical Req. 208/230V, 1-phase
Amp Req. 30 @ 208/230V
Mag Starter Not Req.
Hour Meter No
Auto Tank Drain No
Air Delivery (SCFM @ PSI) 14.0 @ 175
Max. PSI 175

pipsters · Feb 11, 2011

In your situation don't focus on storage. For guys like me with the 120V units, storage is needed. But with a unit that will do, my guess 17-18ish CFM @ 90 PSI (it does 14 @ 175, which is a lot at that high pressure) you will be fine running it continuously doing things like sanding or using it for a blast cabinet. Anything that needs higher flows like an impact won't use up anywhere near that much air, if it does just wait 2-3 mins and let it fill up again.

If I were to build my perfect home compressor it would be about like that snappy unit, 30 gallon horizontal with wheels horizontal build with about 20 CFM @ 90 psi running continuously but capable of filling the tank to 175 psi. At those numbers I don't think there is anything you can't run continuously that would require it (DA sander etc if you want to use air).

SpeedwayRyan · Feb 12, 2011

I've thought about doing something like this, but for occasional use, I've decided to leave my compressor in the corner of the garage where it is.

For one, I drain the water from my compressor when I'm done using it. I know there are automatic drain systems that can take care of this, or you could run a hand-operated valve into the shop, but just something to note. Another thing is that I don't like to leave my compressor sitting full of air if I'm not planning on using it again soon, so I vent it when I'm done working -- again, either automate this, or set up a remote valve to let you do this from the shop area. It's also nice to keep an eye on the pressure, so you might want remotely mounted pressure gauges...for me, it just turns into too much complexity for not enough convenience -- I'd rather listen to the thing run than deal with all that. But, I don't use my compressor all day every day either. If I made my living with it, it would be worth the trouble...but for once a month, I wouldn't bother. I use mine more than that and I'd rather spend my money on something else...but that's just me.

Your attic might get pretty hot in the summer and cold in the winter too...just something to consider (running hot in the summer and condensed water freezing in the winter). Structural loading and vibration are the other issues to consider.

tig · Feb 13, 2011

I just wasted a bunch of time (sitting in an airport lounge in London!) reading this massive thread on compressors:

http://www.garagejournal.com/forum/showthread.php?t=4901

I see a lot of pictures of setups like this with lots of pipes going vertical and different filters here and there. Is there a writeup somewhere I can read that describes the mechanics/physics of what poeple are trying to accomplish by doing this?

impulse922 · Feb 13, 2011

tig said:
I see a lot of pictures of setups like this with lots of pipes going vertical and different filters here and there. Is there a writeup somewhere I can read that describes the mechanics/physics of what poeple are trying to accomplish by doing this?

They are trying to cool down the highly compressed hot air. When it cools back down it creates water in the air lines. The idea is to cool it down plenty by the time it gets to the drier so that it doesn't cool down even more in the air line and **** out your air tools.

51rider · Feb 13, 2011

tig said:
I just wasted a bunch of time (sitting in an airport lounge in London!) reading this massive thread on compressors:

You should have dropped me a PM-I can get to most of the London airports easily. Would have been great to meet a fellow GJ member.

Maybe next time?

pipsters · Feb 13, 2011

impulse922 said:
They are trying to cool down the highly compressed hot air. When it cools back down it creates water in the air lines. The idea is to cool it down plenty by the time it gets to the drier so that it doesn't cool down even more in the air line and **** out your air tools.

Running a 1/2" ID line from a compressor pulling 25 CFM (typical 1/2" impact load) the air speed is over 300 feet per second. That means in a 50' run the air passes thru in 0.17 secs. I have to laugh at people when they say the above (not at you) because how much cooling is done in 0.17 secs?

The way to cool air is either with a specially built cooler/drier ($$) or to expand it. In aviation, you take high temp compressed air and expand it, run outside air over it to cool it, compress it again, expand it, run outside air over it again, compress it, and repeat one more time. This can cool 500+F air to sub zero temps (Google "PACK").

If you want a home use application, and I've never tried this, but I would run the compressed air to a large tank where it expands and condenses out the moisture, then from there out of that tank to your line. If you want to go nuts, you'd bury that tank underground to maintain a lower temp of say 50-60F.

If you don't believe me, look at what a commercially bought direr is, it's a small expansion tank with a decadent in it of some sort. You expand, condense moisture, take it out, then condense again (going out the other side).

tig · Feb 22, 2011

tig said:
How do you folks think this SnapOn unit would meet my requirements (assume I can get it slightly used/cheap). The only downside i see is the relatively smallish 40 gallon tank; but for my infrequent use I doubt that will be a problem.

http://buy1.snapon.com/catalog/item.asp?store=snapon-store&item_ID=77751&group_ID=13098

Stock # BRA5140H
Name Air Compressor, Stationary, 40 gallon, 5.0 HP, 175 max. PSI
Price** $2,443.85
Brand Snap-on
Country Of Origin Canada
Horsepower, HP 5
Pump Stages Dual
Tank, gal. 40
Tank Style Horizontal
Electrical Req. 208/230V, 1-phase
Amp Req. 30 @ 208/230V
Mag Starter Not Req.
Hour Meter No
Auto Tank Drain No
Air Delivery (SCFM @ PSI) 14.0 @ 175
Max. PSI 175

Score! I was able to purchase this compressor via craigslist for $850. It's in almost brand-new condition and the guy threw in a 2nd 60 gallon tank I can optionally plumb in if I want.

Now on to adapting my air plumbing.

I need to get an automatic tank drain. Anyone know of a good source that sells them. I haven't been able to find them for sale in the usual places.

tig · Feb 26, 2011

And here she is!

As you can see this Snap-on model BRA5140H is in near brand-new condition. The extra 60 gallon tank that the seller threw in looks completely serviceable but I'm not sure I'm going to use it yet or not.

I might plumb it in such that I can optionally use it, decreasing the time to fill the tank in most cases. Thoughts on that idea?

Not bad for $850 I think.

tig · Feb 26, 2011

Question:

If I wanted to adapt an hour meter to this compressor, how would I do that? How do hour meters work? Ideally I'd be able to remotely mount the hour meter separately from the compressor (since it's going to be in the attic)?

tig · Feb 26, 2011

tig said:
Question:

If I wanted to adapt an hour meter to this compressor, how would I do that? How do hour meters work? Ideally I'd be able to remotely mount the hour meter separately from the compressor (since it's going to be in the attic)?

I think I just answered my own question by reading this thread ...

Which, in summary, says "If it's used infrequently just change the oil regularly...like every few years. Plus if you use a timer based automatic drain then the compressor will run every few days keeping things lubricated."

I have already ordered this automatic drain:

scott37300 · Feb 26, 2011

Nice compressor. Looks like a rolair pump, very similar to my rolair except my head is different and is a two stage. But the oil drain, sight, and fill/vent looks just like mine. And for some reason that 303 stamped in it sounds familiar.

tig · Feb 28, 2011

Anyone have thoughts on the pros/cons of me plumbing in the 60 gal tank in with this Snap-On compressor?

If I simply connect the output of the 40 gal tank to the input of the 60 gal tank it'd be the same as having a 100 gal tank, right?

Pros:
* Longer run time
* May help keep the air cooler (see @pipsters post above)

Cons:
* Will take longer to fill
* More couplings to go wrong
* Requires 2 tank drains

Anything else you with more experience can think of?

fordbroncodave · Feb 28, 2011

thats a very nice snap on compressor. i was going to buy it at one point in my life but i settled on something else for the time being

scott37300 · Feb 28, 2011

If it were me I would hook it up so you can use just the SO tank when you only need 40 gallons, or add the 60 when you need the extra capacity. A couple valves can do this pretty easy, or even a hose with quick connect.

Yes this would give you a "100 gallon" tank size.

You wouldn't need another drain on the craftsman, if you are only using it every once in a while I would just drain it from the tank drain when done using it.

tig · Feb 28, 2011

scott37300 said:
If it were me I would hook it up so you can use just the SO tank when you only need 40 gallons, or add the 60 when you need the extra capacity. A couple valves can do this pretty easy, or even a hose with quick connect.

Yes this would give you a "100 gallon" tank size.

You wouldn't need another drain on the craftsman, if you are only using it every once in a while I would just drain it from the tank drain when done using it.

Thanks.

The problem is both the compressor and the 60 gallon tank will be in the attic which will not be easily accessible. Thus I'd have to do some sort of remote valve. I have tried to think of a way to put the 60 gallon tank downstairs, but while it's possible, I don't want to waste the floor space.

Serj · Feb 28, 2011

one possibility is you could have the drain valves piped to a shared outlet, then you only need to use that one automatic drain timer you picked up. one would think based on pipster's post above is that the majority of cooling and condensation would occur in the remote, 60gallon tank, so i would tend to think that's a bigger deal to keep drained. you could facilitate the draining of both and temporary use of the 60gal with a closable valve up top (close when you don't need the extra 60gallons) and at the drain put a one-way check valve on the 60gallon side so on a drain cycle it doesn't inadvertantly pressurize the 60gallon tank.

scott37300 · Feb 28, 2011

tig said:
Thanks.

The problem is both the compressor and the 60 gallon tank will be in the attic which will not be easily accessible. Thus I'd have to do some sort of remote valve. I have tried to think of a way to put the 60 gallon tank downstairs, but while it's possible, I don't want to waste the floor space.

You can make a valve setup that comes down out of your ceiling and supplies your air lines. Here is a picture but you could adapt it to fit your needs.

Grinder Bill · Feb 28, 2011

Interesting idea... Not suitable for cold climates though; I take it you live someplace warm...?

As for maintenance issues, I'd suggest a few things:
1) put a valve on the compressor oil drain then cap or plug the valve finger tight only. You could also run an oil drain line to ground level. The idea is to minimize tools and dirty oil handling in the attic...
2) mount the compressor in a drip pan of some kind (see #1)
3) put a light & switch above the compressor
4) if you're wiring the motor direct, put a disconnect at the compressor (or an alternate method of positive isolation to keep little fingers from messing up your day while you're in the attic...)

tig · Mar 7, 2011

Used pickup truck on the Backyard Buddy lift to raise the compressor and tank to the attic door. I didn't take a pick of the scaffolding we put on the bed of the truck sorry.

Compressor and tank in attic!

Next up get it plumbed in...

tig · Mar 9, 2011

I do not have a manual for the Snap-on BRA5140H compressor. Can anyone provide instructions on how to set the output pressure? I just want to make sure I'm doing it right.

The issue I have is my secondary 60gal tank has a pressure relief valve that maxes out at 120psi. The Snap-On wants to keep going past 150psi+. I don't think I need more that 120psi in the tanks and want to dial the snap-on back to 120.

I'm going to run my air regulator at ~100psi.

EDIT: Never mind - called Big Red and they stepped me thorough it. The top adjustment screw is the cut-out adjustment. The bottom is cut-in. The cut-in is set to be 30 psi delta from cut-out. Turning cut-out counter clockwise adjusts the cut-out down.

I performed the adjustment and now the compressor cuts out at 145psi. My regulator is set for just below 100psi. Just used the compressor "for real" for the first time adding some air to the tires of the FJ40 and my hand dolly. LOL.

tig · Mar 9, 2011

The compressor install is basically DONE!

Here are some pics:

Here's the attic with the compressor and 60 gal tank all plumbed in.

Here's the auto-drain.

The auto drain is pumbed to a tube that runs out the eve of the garage to the ground:

And the plumbing to the 60 gal tank and my air regulator/filter:

pipsters · Mar 9, 2011

Depending on the size of your line and how long it is, you'll want to run a lot higher pressure coming out the tank than 100 psi. In fact, if I were to have something like that set up, I would run full pressure and use a regulator downstairs at the tap. IIRC using 3/8" line a 50' run loses 20 or so PSI. So 100 coming out the tank will be 80 at the tool.

With mine, once I get it set up, I plan to have two taps, one regulated @ whatever (probably 110 psi accounting for some loss in the hose) and the other unregulated to run full pressure (150 psi in my case).

You can probably easily and cheaply replace the Craftsman tank pop off valve. They are a few bucks, and can buy one rated for 150 psi. This will allow you to store more air with longer times in between your compressor kicking on.

scott37300 · Mar 9, 2011

Couple of things I see.

First, the auto drain is higher than the bottom tank drain. I would think you would want the auto drain lower than the drain on the tank, but maybe the pressure will blow the water out?

Second is an observation about your insulation. Your whole attic looks to be insulated but then you have 2 vents and I assume more vents on the other side of attic. Doesn't this deffeat the purpose of insulation? Or do you cover those vents in the winter? Also those vents should be above the flat area of the trusses and not sure if you do or not but there should be eave vents and foam baffles along the roof sheathing on the angle part of your trusses.

reinhardt · Mar 9, 2011

before you swap the pop off valve (relief valve) for a higher one, verify the tank is rated to support the higher pressure. should be stamped on a tag on the tank.

ben

Air compressor in garage attic - Not your typical compressor thread

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Active member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member