# Air Compressor Drain Replacement : Warning Picture Heavy



## abrace (Jan 30, 2016)

In my garage (not the shop that I am building) I have a 15 year old craftsman 60 gallon compressor. It is an oil-less model made by Devilbliss, with a "2.9" HP motor. Compressor is direct drive.

I have dreams of replacing the motor and pump, as I have a brand new oil pump, but since it is my only compressor at the moment I can't afford to have it out of commission while I monkey around with the upgrade. I have a 5HP Quincy QT on order for the shop, so once that is in and I get the town off of my back for inspections, I can redoing the craftsman.

Anyways the drain at the bottom of the tank stopped turning easily. Too much rust built up and it got jammed because it was always such a PITA to drain it. So, now since I can't close it all the way and it leaks, I had no choice but to address it. I figured I would share as there has to be someone else out there that could use this info.

First step was to take the plastic cowling off of the top. Then you see what a bunch of nothing these units are. The plastic cover makes them look a lot more stout than they really are.




On the plus side, since the motor and pump are such a joke, the thing only weighs about 190 lbs. So with my wife's help we were able to carefully lay it down on the ground and work on it. Here is a shot of the bottom with the drain showing. It is all chewed up because I had to resort to using slip joint jaw pliers to open and close it for the last few months (till that even stopped working 2 weeks ago)




The drain came right out with a box wrench, easy as pie. Wasn't in there super tight. After I removed it I could see silt/rust through the hole. Poked it out with a screw driver. Not sure how long this tank has to live. Below is a shot of the drain after it was removed, and the hold in the bottom of the tank with the sludge showing.








I am replacing this drain with a brass street elbow, 6" brass nipple, ball valve, and another street elbow to redirect the junk towards the ground for safety when I drain/burp it. All parts are 1/4" NPT

The below shots are it being installed. I used pipe dope.








And the tank was stood back up and bolted down, this is the finished product. Nipple could have been another inch longer, but I made it work.



Next problem was to adjust the pressure this thing runs at. It is factory set for a 140ish PSI cut in, 175PSI cutoff. That is a ridiculous pressure for this level of machine and the last 30PSI takes forever. I wanted to lower it down to something more reasonable, and since it is a dual stage, I still get the efficiency advantages of the cooling effect of the compressed air moving between the two stages (through the intercooler, which is nothing more than an extra 12" of tubing bent into a U shape, but it is better than nothing). The pressure switch is 'non adjustable' but a cheap keyed torx bit took care of that. I got it down to a 110PSI cut in and a cutout of about 145PSI. It really couldn't go any lower than that with this pressure switch. I expect this will help the unit perform better overall.




Thought I would share my morning of polishing this turd up a bit, hopefully it will buy some time.

All in all, the brass parts and valve cost me about $20, so I probably doubled the compressors value. That said I should have done this years ago.


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## jpfabricator (Jan 30, 2016)

Plus one on a ball valve.
Good job

Sent from somewhere in East Texas Jake Parker


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## Billh50 (Jan 30, 2016)

I have been wanting to do that to mine. Maybe I should do it now before I have problems.


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## TOOLMASTER (Jan 30, 2016)

i use a timer and a solenoid valve..drains for 2 seconds every day(changable)..with a manual button for heave use


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## abrace (Jan 30, 2016)

TOOLMASTER said:


> i use a timer and a solenoid valve..drains for 2 seconds every day(changable)..with a manual button for heave use



I ordered my new Quincy with an automatic drain valve. They are nice.

This craftsman I put the valve on gets intermittent use.

---Aaron


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## FOMOGO (Jan 30, 2016)

That's one of those jobs that just makes life a lot more pleasant for a small investment in time and materials. I've done the same thing to all of mine even the portables. The two big ones going in the new shop will be getting auto-drains. One less thing for my increasingly foggy mind to have to keep track of. Mike


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## onetrack (Jan 30, 2016)

That's good work that improves the original design - that is basically cost-cutting at the expense of important accessibility.
Down here in the underworld, 98% of air compressors have a horizontal air receiver. The vertical receiver appears to be the major design in the U.S.

I have a nice big U.S.-made vertical air compressor, made by a company called C.A.S.E. (Compressed Air Supply Engineering, I think was the origin of the name.) The company appears to now be defunct.
My compressor was sourced from a car wash that was being demolished, and I scored it for $200!
It still had the original top-notch Lincoln Electric 5HP motor, but the original compressor head had apparently failed, and someone had fitted a cheaper and much smaller Italian Peerless compressor head.
The Peerless head was waaay below the motor and tanks potential, so I sold the Peerless head and sourced a new 3 cylinder, Taiwanese Fu Sheng compressor head - which produces around 28cfm FAD with ease and really turns the compressor into the beast it probably was originally.

However, the big bugbear with this unit is the same problem you encountered - an inaccessible drain that is mounted too low to the floor for access, anyway (the receiver sits on 3 legs, but the drain nearly touches the floor.
I was considering raising the receiver by installing additional length to the feet - but your idea of a fixed drain extension with an easily accessible tap is a much better way of attacking the problem. Thanks for the heads-up.


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## David VanNorman (Jan 30, 2016)

I wondered why you laid the tank down till I seen how much of a pain it was. The Quincy is a real machine . Most people don't drain their compressors as often as they need to.


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## cvairwerks (Jan 31, 2016)

Onetrack: Instead of hard plumbing the new drain, convert to a flex line and put the drain where it's convenient to you. We did that at one shop I used to work in. Compressor was buried under a staircase and a brute to drain. I replumbed it with the drain valve at an easily accessible  location and no more problem to drain.


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## uncle harry (Jan 31, 2016)

cvairwerks said:


> Onetrack: Instead of hard plumbing the new drain, convert to a flex line and put the drain where it's convenient to you. We did that at one shop I used to work in. Compressor was buried under a staircase and a brute to drain. I replumbed it with the drain valve at an easily accessible  location and no more problem to drain.



At a shop/lab that I managed when working we installed a timed automatic drain & routed the moisture outside through the building wall with nylon air tubing. It worked great & the air in the lines was kept relatively dry. Now it's time to do the  same @ home.


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## juiceclone (Jan 31, 2016)

if u look around online/eBeast, there are auto drain fittings u can adapt. they usually dump momentarily when the compressor shuts off.  read description carefully as some require special controls to operate.   if u can, look at a compressor with auto drain to scope how they work.


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## great white (Jan 31, 2016)

TOOLMASTER said:


> i use a timer and a solenoid valve..drains for 2 seconds every day(changable)..with a manual button for heave use


care to add a few details?

As in: what type of components to look for if wanting to duplicate?


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## TOOLMASTER (Jan 31, 2016)

i use industrial timers ...set the first one to 999 minutes...that is your interval....then the second one is your air duration...i set it for 2-5 seconds depending on usage..
then a 1/4" solenoid valve under the compressor.


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## TOOLMASTER (Jan 31, 2016)

now you don't have to make your own like i did mannnny years ago

http://www.amazon.com/Electronic-Automatic-Tank-Drain-Compressors/dp/B00273WV78


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## abrace (Jan 31, 2016)

TOOLMASTER said:


> now you don't have to make your own like i did mannnny years ago
> 
> http://www.amazon.com/Electronic-Automatic-Tank-Drain-Compressors/dp/B00273WV78



If I bought that for the craftsman I put the ball valve on yesterday it would quadruple it's value.

Saylor Beall has a neat drain on their compressors. It is pneumatically operated and triggered by the unloader. So every time the compressor stops it triggers the drain. Doesn't require any 110V power like most of the other automatic drains since alot of people don't have 110V close to their 220V compressor and would need to resort to extension cords.


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## Silverbullet (Jan 31, 2016)

When we moved mine I did the same thing only I hard piped it thru the wall to the outside , I added a ball valve to drain it plus I installed a quick connect there also. I can run hoses in the back of the garage instead of around the whole thing. I have the auto drain on mine also but it seems to hang up often even tho I have it set for 5 seconds every 45 mins. So I just use the ball valve.


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## gr8legs (Jan 31, 2016)

I'm not sure how good the quality is but we used a $9 Harbor Freight automatic drain kit on our compressor. I really should check on it when the weather clears and make sure it is still working lest I end up with half a tank of ugly water.

http://www.harborfreight.com/automatic-compressor-drain-kit-68244.html

It appears to be pretty much the same device as the 'high price spread' - it works on the differential pressure when the cutoff/unloader valve opens at the end of a compressor cycle.

Stu


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## DKD228 (Feb 1, 2016)

Silverbullet said:


> When we moved mine I did the same thing only I hard piped it thru the wall to the outside , I added a ball valve to drain it plus I installed a quick connect there also. I can run hoses in the back of the garage instead of around the whole thing. I have the auto drain on mine also but it seems to hang up often even tho I have it set for 5 seconds every 45 mins. So I just use the ball valve.


I have the same "Craftsman Professional " compressor and had nothing but trouble when I put on an auto drain right after I bought it some 15+  years ago. After a few months with auto drain 
screwing up all the time, I switched to a ball valve setup.   I think the problem lies with the "oilless compressor"  design adding way too much HEAT ( and therefore moisture ) to the air being 
compressed.  The units have sadly inadequate cooling fins on the cylinders and no help at all from the transfer tube ( intercooler ? ).  The manufacturer(s) also run these things at very high RPMs
 in order to get ( barely ) the air pressure and volume they claim in their specs.  They do OK overall, if not run to death, so I guess " we got what we payed for "  in the end.    BTW, I always shut 
the power off to mine whenever I leave the garage.


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