air compressor dryer

[70Tom]

Hi. I just posted this in the Ask RapidAir! thread, but I wasn't sure how much traffic it might get (and the question is directed at one person), so I'm starting my own thread. Hope that's ok.

I just purchased a C-Aire A075V080-3230 7.5 HP 208-230 Volt Three Phase Two Stage 80 Gallon Air Compressor, along with a RapidAir 3/4" MaxLine 100 ft master kit for my home shop.

I have restored several vehicles over the years, and other than for a short period of time, I've never had a really good compressor. Well, I've never had a compressor as good as this one, period.

I bought it to allow me to work on all phases of vehicles, including rust removal (blasting) and painting.

I'm located in Phoenix, AZ, so humidity is a non-issue, but air temps obviously are. I won't be painting full time, but will paint projects here and there, as need be. As I dropped a ton of money (for me) on the compressor, I'm not in the market for a really expensive dryer system (I've seen many that are $1000+) at the moment.

My question is this: what air dryer/filter system would you recommend?

Thanks for the help.

 

[arrowhead]

i got the Harbor Freight refrigerated air dryer and never looked back. Use it all the time and have painted 4 cars with it. Say what you will about HF, but it's been a good unit and with a discount coupon it's almost as inexpensive as all the copper tubing, fittings and valves people buy for home made contraptions.

https://www.harborfreight.com/compressed-air-dryer-40211.html

 

[70Tom]

i got the Harbor Freight refrigerated air dryer and never looked back. Use it all the time and have painted 4 cars with it. Say what you will about HF, but it's been a good unit and with a discount coupon it's almost as inexpensive as all the copper tubing, fittings and valves people buy for home made contraptions.

Wow. Thanks. I had no idea they even had one, and it has good reviews as well.

 

[Bretny]

I have a split maze of 1/2in copper between the compressor and tank. All my water is collected before the tank thus not needing further drying and saving my tank from rust.

 

[engineer2]

HF honors the 20% and 25% coupon for the Air Dryer in the store?
That would be good news.
I priced it on the website and it wouldn't accept coupons.
I'm not sure how much longer my 52 year old IR air dryer is going to last.
I hate to keep feeding it a shot of R-12 every year, so an HF unit is on the horizon.

 

[bczygan]

Picked up one free.

Any will do the job.

Look at the inlet temperatures and pick the one that fits.

I will have the copper maze before it, to cool the temp adequately before the cooler.

Bill

 

[70Tom]

HF honors the 20% and 25% coupon for the Air Dryer in the store?
That would be good news.
I priced it on the website and it wouldn't accept coupons.

I was wondering the same, no go for me online as well.

 

[70Tom]

I also notice that the Harbor Freight unit says it accommodates compressors up to 21.6 cfm, 140 psi. My compressor puts out 24 cfm @175 psi. However, I can't see ever using that much pressure on anything. Also, I'm guessing there's some pressure loss by the time it gets to the air dryer. So probably nothing to worry about.

 

[Kaizen]

I also notice that the Harbor Freight unit says it accommodates compressors up to 21.6 cfm, 140 psi. My compressor puts out 24 cfm @175 psi. However, I can't see ever using that much pressure on anything. Also, I'm guessing there's some pressure loss by the time it gets to the air dryer. So probably nothing to worry about.

For your environment I think I’d just run the dryer on one leg that you would use for painting and blasting. No sense running it all the time if not needed nor to be forced to reduce air pressure on the whole system.


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[Kaizen]

I have a split maze of 1/2in copper between the compressor and tank. All my water is collected before the tank thus not needing further drying and saving my tank from rust.

Did you do any write ups on this? Interested in this approach for a new tank I’m hoping to get


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[SickSpeedMonte]

I had my HF refrigerated air dryer delivered last year and it showed up a little beat up. Pretty typical from what I remember reading. I went to the store for one and they didn't stock them but I thought I was able to take advantage of a discount somehow. I did have a small pinhole develop in the hard line (air side, not refrigerant) inside of the thing after a few months and brazed it up and it's back in business.

 

[engineer2]

i would think the pressure limitation is due to the water drain system. If you add your own, no need the worry about theirs.

 

[Lucky13driver]

I've seen some guys put a trans cooler between the compressor head and the tank and have had decent success.

 

[like2wheel]

Wow. Thanks. I had no idea they even had one, and it has good reviews as well.

Not sure I agree with this. If you read the reviews, even many of the 4 star have problems. Let alone what all the 1-3 star reviews had to say.

That said, the price is hard to resist. I'll prob take a chance on one someday...

 

[UglySign]

I've seen some guys put a trans cooler between the compressor head and the tank and have had decent success.

Hayden 1260/1290 ? I've put a small 10 gal tank after that to collect the water before the tank w/ auto drain. Works pretty good for now until I get to finish it off. WIP.
Get good hoses also along with filters sized for your outlets.

Alot of good info on the Compression - Show Off Your Compressor thread

 

[engineer2]

Even if it is a bit sketchy, it's a pretty simple refrigeration system. If something goes wrong, it should be an easy fix. About the only fatal defect would be a leak in the refrigerant-to-air heat exchanger.

 

[like2wheel]

Anybody know what kind of refrigerant it uses?

 

[engineer2]

Anybody know what kind of refrigerant it uses?

134a

 

[Bretny]

Did you do any write ups on this? Interested in this approach for a new tank I’m hoping to get


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Sorry no. You want to expand the pipe to get the moisture to drop out/cool the air. I did this by a manifold of tees.

I have about 30' of 3/8 coiled copper before this 1/2in split maze. I have a poly line from the 1/2in copper to the tank..that tells you how cool the air is going into the tank. The setup is about 10yrs old.

 

[Kaizen]

Sorry no. You want to expand the pipe to get the moisture to drop out/cool the air. I did this by a manifold of tees.



I have about 30' of 3/8 coiled copper before this 1/2in split maze. I have a poly line from the 1/2in copper to the tank..that tells you how cool the air is going into the tank. The setup is about 10yrs old.

So out of the compressor it’s still coiled and doesn’t rattle when running?


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[pcmeiners]

https://www.garagejournal.com/forum/showthread.php?p=556948&highlight=db1290

 

[engineer2]

If you get a refrigerated air dryer, you don't need a maze of aftercooler tubing. An air dryer does a better job removing moisture than any aftercooler could do.

 

[pcmeiners]

True but an after cooler provides cooler/dryer air so the refrig unit can produce dry air at a lower cost and more efficient, especially since an after cooler uses very little power to cool air. Most refrig dryers want input at near ambient temperature, not at 200- 300 degrees, which could happen if a compressor is being used constantly for extended periods. Many refrig units have a pre-cooler coil, but most are undersized.

 

[engineer2]

True, pre-cooling will save energy. There are high-temp input air dryers that can take air right from the tank. It's a pretty common set up for industrial applications. They use more energy because they often are designed to run continuously instead of cycling.

Does the HF air dryer run continuously or does it cycle the condensing unit?

If the compressor tank temperature reaches 200-300 degrees I would think that's abnormal. I've never seen a tank that hot.

 

[bsaint]

True but an after cooler provides cooler/dryer air so the refrig unit can produce dry air at a lower cost and more efficient, especially since an after cooler uses very little power to cool air. Most refrig dryers want input at near ambient temperature, not at 200- 300 degrees, which could happen if a compressor is being used constantly for extended periods. Many refrig units have a pre-cooler coil, but most are undersized.

You should see how much hot refer is passed onto the evap with a hot gas bypass to keep the heat load right. Most of the time your air isn't hot enough to turn the refer back into vapor. Most air dryers are also NOT cycling at the cfm he needs.

I have a customer with our brand of air dryer without a aftercooler in a 115*F-120*F room in the summer and it doesn't skip a beat.

OP - if you're really interested we sell the BEST brand of air dyers. 5 year full warranty. No pro-rated ****. I could drop ship you one for a killer deal. PM if you're interested. With paint you want at least a 33*F dewpoint which not all refer dryers have either.

 

[engineer2]

^^ Tell us about your air dryers.

 

[bsaint]

^^ Tell us about your air dryers.

Okay so they have stainless steel evaporators. So right away they beat all the ****** European ones with aluminum evaporators (i.e. kaeser, Sullair, MTA, etc). They are charged with easy to get r134a that you can pickup anywhere. Not 407c. They all have hot gas bypasses. They all have electronic timer drains that so far have lasted years without dying. Those ****** float bowl drains die at least once a year with the crust that comes through a dryer. They have oversized cabinets so they are a cinch to work on.

**THEY ARE MADE IN MICHIGAN**

All parts I can get at a refer store locally if I needed too. I mean the list goes on. I dont know a better air dryer.

 

[pcmeiners]

Not saying there are many rferig units which work great. My point, with an after cooler, for almost no power use , temp outlet is near ambient, 65% of water drops out, a great deal of latent heat of condensation is dispersed for nothing. Yes a really expensive refrig unit will have a large pre-cooling coil which will act as a decent after-cooler, but that is not common.

 

[bsaint]

Not saying there are many rferig units which work great. My point, with an after cooler, for almost no power use , temp outlet is near ambient, 65% of water drops out, a great deal of latent heat of condensation is dispersed for nothing. Yes a really expensive refrig unit will have a large pre-cooling coil which will act as a decent after-cooler, but that is not common.

The OP said he wants to paint. If inlet temperature in 100*F out of the tank and ambient humidity is 14% like today, your dewpoint is still 45* which is too high for painting.

 

[engineer2]

So how much is a unit in the 10 cfm or 15 cfm range?

 

[pcmeiners]

"The OP said he wants to paint. If inlet temperature in 100*F out of the tank and ambient humidity is 14% like today, your dewpoint is still 45* which is too high for painting"

We all have gone off topic from the OP. In Arizona when I was there high humidity was under .5%. So an after cooler/frig unit would only lower the output temperature, humidity would not be an issue.
Bsainter, I never meant further moisture removal is not needed after the output of an after-cooler. If they had 14% humidity in AZ they would declare it a national disaster zone.

"Okay so they have stainless steel evaporators."
Nice, agree most companies cut back quality for profit. Aluminum fins just do not do it for me.