Junair Air Compressor help

Goldjockey

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Thread starter #1
I've got an old Junair 25L, model number 1452000. Had it since 2006. Moved it recently and heard water sloshing around in the air tank. There's a large drain plug on the very bottom, but I don't think it's been off since the compressor went into service when it was brand new.

The compressor still runs like new. I'm a jeweler and not an air compressor mechanic, but I'm betting that someone here on the forum has one of these, and can guide me as to how to remove the drain plug and dry out the tank without screwing anything up.

Thanks in advance for your help!

Mike
 

papart1

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#2
yes sir..........just a plain plug? 4 sided? Heat with a propane torch,a little butane guy would work too. Blue flame tip just at the collar of the thread-0-let, (plug goes in iT) .........say 20 to 30 seconds, stop and spray PB blaster on.....it'll stink a bit. Brace the tank and take the plug out with a 10-12" creasent wrench.
 

T.G.III

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#3
^^^^^^^^^^^^

What Pap said, old school plumbers solution to remove a stuck plug. You'll want to position the tank so as to manipulate the water away from the plug while applying the heat as the water will draw the heat away from it's intended purpose possibly creating steam that could build pressure in the tank leading to an unsafe situation. also make sure the tank is completely bled off before you start due to previously mentioned safety issue.

Hooking up an open ended air hose would eliminate the pressure building safety issue.
 
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Leonardo

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#4
Hi Michele!
I do not think that the plug is stuck. I never needed to heat up one of these.

These drain plugs are usually made of brass with a conic sit so just unscrewing a couple turn will suffice to let the water start draining.

First release the air pressure and let the air escape of the tank till its empty, then look for a place to drain the water. The water contained in the tank will be really dirty and brown because of the oxide of the internal wall of the tank and may ruin your floor.

If the drain valve is to one of the sides of your tank you may want to tilt the compressor a bit to that side. After a while, when you are sure there is no pressure in the tank, you can take the plug all the way out, let the water drain totally, clean the plug and screw it again in its place.
Do not tighten the plug very hardly. Many of these plugs are made to be operate just by hand with a cross bar or a knurled surface.

Please excuse the bad pictures but anyway, this is my 100 litres dirty compressor and its valve:

fr_364_size1024.jpg

fr_363_size1024.jpg

You will need to unscrew just the knurled part of the valve not all the valve (the hex part) out of the tank.

Hope this helps a bit!
 
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mitch

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#5
Step 1) Unplug it. Don't just turn off the switch.
Step 2) Bleed all the pressure out of the tank until gauge reads 0 psi.
Step 3) Are you sure the plug is the ONLY drain? If it's a factory unit- not modified by a past owner, it really, really should have some sort of a drain valve. It's possible that a past owner got tired of the valve leaking/dripping/clogging (a very common problem) and replaced it with a plug, figuring they'd just take it out whenever necessary.
Step 4) Drain it well and replace with a ball valve & tubing to make future draining easier- and thus more likely to be done regularly.

NOTE: Rust and crud can and will build up over time in the new valve and you'll occasionally have to poke a nail or wire through to clear it. You'll want to bleed all pressure out of the tank before doing that. I can attest that 20-30psi is still plenty to make a big exciting mess when you punch thru that rust plug...
 

Dave London

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#6
Also from a dumb old plumber turn it on its side and use kroil pentrating oil at the threads let it sit over night, then A large wrench
 

papart1

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#8
don't know yet if it's a bleeder style, brass........or a iron plug 4 sided.........so lots of speculation and no answers yet. Could also be a socket style plug which would mandate a allen wrench.........so many questions.................pics would be nice too
 
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#9
Just checked my Jun-Air, it’s got just the this valve to get the water out, no plug at the bottom of the air tank.

From my own bad experience, when I let the water out the first time after buying the compressor: this could be messy, rusty water and oil stain clothes and floor quite effectively...

Cheers

Ralf
 

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Goldjockey

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Thread starter #10
Thanks to everyone for the help. Wish I had a picture of the plug. It's literally on the very bottom in the middle of the tank, and I'm concerned that if I tip the machine too far to one side or the other, oil will go where it shouldn't.

I'll see if I can get a snapshot and post it tomorrow.
 

allan621

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#11
I've had this problem with my silent air. I commented to someone who came over to pick up some work that I might need a new compressor since it was running a lot more frequently than it used to. He looked at my compressor, took a small bucket from the corner of the shop and a lot of paper towels. He lifted the compressor on a stool so the plug was off the floor. Then a small pair of vise grips and started to loosen the plug a little since it was pretty stubborn. Then he used a textured rubber square that I use to open stubborn jars lids and used it to open the nut all the way and the water came out. Nearly filled the bucket. When the water was almost out he turned on the compressor again to flush any remaining liquid out the air compartment and used the paper towels to block the spray from the remaining liquid. Put the nut back in and tightened it until the air stopped leaking through the plug.

That was about ten years ago, and the silent air still runs fine. But I make sure I open the plug twice a week and drain it.

Allan
 

Goldjockey

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Thread starter #12
Great post, Allan. Since this is likely to be something I will need to do periodically, I think what I'll do is invest in a wooden stool, cut a 4" diameter hole in the center, rest the Junair on top of it with the drain centered over the hole, and remove the plug from the bottom draining into a small bucket positioned underneath. This will eliminate the need to tip the machine on its side, and mitigate the risk getting oil in the compressor head.

Thanks to all for your advice and suggestions!
 

papart1

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#13
oil is sucked up through the center hole of the motor to the head anyway to lube the head and the crank pin, piston rod and piston
 

Goldjockey

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Thread starter #14
Just checked my Jun-Air, it’s got just the this valve to get the water out, no plug at the bottom of the air tank.

From my own bad experience, when I let the water out the first time after buying the compressor: this could be messy, rusty water and oil stain clothes and floor quite effectively...

Cheers

Ralf
Hello Ralf,

Set up my engraving bench today in the new workshop here in San Leon, Texas.

There is a large drain plug on the bottom of my Jun-Air 6-25. Didn't take a snapshot, but it's right at the bottom of the tank, pretty large, about 2.5" (6.4CM), and I thought..." well, this kind of looks like a 'last resort solution', big pain in the ass, can't believe a company that sells these damned compressors for nearly 3K has this kind of half assed engineering" (grumble, grumble, grumble.... lots of swear words).

Still unpacking my tools and looked up and down for a pipe wrench I knew I had but still can't find, and swore even more!

Then I thought.... "Google". "Google and find a damned manual, goddamnit!!!"

Well, I googled, and there was a list of compressor specs and manuals as long as your arm with all kinds of pictures and diagrams that looked nothing like what I had, and the list went on, and on and on.......

Finally, I searched for the term "6-25" and there it was...... It showed a pictured of the compressor (mine!) and a picture of a knob on top which didn't quite look like the knob on my compressor.

The instructions said to push down on the knob (which was weirdly on the top of the tank as in your photo) to drain water. Well, I pushed down, and nothing happened.....

Alright.... the knob had grooves in it, so I gritted my teeth expecting to break it, and turned it counter clockwise...

Success! Although the tank was mostly depressurized, a bit of rusty water sputtered out of the nozzle. That was encouraging, so I fired up the compressor, set a bucket up directly under the nozzle, let the compressor get up to pressure, and opened up the valve.

A pressurized steady stream of rusty water poured out of the valve, and finally petered out, with a bit of ancient oil oozing out as the last effluent.

Problem solved!

YMMV.
 

John B.

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#15
Hello Goldjocky,
I have the same drain system. I installed a plastic hose, using a small hose clamp, to the nozzle on the top of the tank. Drilled a hole in the cap of a half-gallon juice jug to fit the end of the hose. No splash or mess when I drain my condensation water and juice jug only needs draining about once a year, YRMV.
 

John B.

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#18
Great advice, John. I'll do that next time I need to drain the tank. Thank you!
Thanks Michael,
I failed to say that I also drill a couple of small vent holes in the cap of the bottle to release the
pressure when draining the tank.
And hold a shop cloth over the cap/hose area while venting the tank.
 

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