draining the tank on a piston compressor

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yavniella

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Hi everyone! I have a piston airbrush compressor with the air tank. I would like to drain the tank, but not sure how to do it. At the bottom of my compressor is like a large bolt which looks like it needs some type of tool to unscrew. It doesn't look like the release mechanism that I have seen at the bottom of other compressor tanks. On the other tanks there is valve extending out of the bolt looking thing. Do I need to use a certain tool to drain the tank or am I missing the valve? If I can drain the tank, does the pressure need to be built up (with the compressor off) when I drain the tank?
 
It is probably a drain, it is most likely a 2 piece unit, and you just need to unscrew it a bit to let air and moisture out. I have one that is knurled for grip. Yours may have a hex for the same reason. Try loosening it a bit until you hear air escape and or water. Might be a good idea to turn the compressor off, drain it all
the way, then open the plug/drain valve, and tip it to investigate to make sure it's not just a plug.

similar to the pic i am attaching.
aze5yby7.jpg



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That drain plug is your best photo realistic piece yet wayne !! OUTSTANDING
 
Here is how mine looks. I just want to be sure before I go tampering with things. Somewhere I read that the tank should be drained if there is a valve and the only pics of valves that have seen look like yours. I have not seen any with just the bolt. image.jpg
 
I don't think that the part you show on the pic is for draining, it looks like it's welded to me. So i wouldn't temper with this. The thing you would be looking for should look like the marked area in the pic i attached. Piston tank.jpg
 
I don't think that the part you show on the pic is for draining, it looks like it's welded to me. So i wouldn't temper with this. The thing you would be looking for should look like the marked area in the pic i attached. View attachment 22961

That looks like the Safety Valve to me, not for draining. I am definitely NO expert though.
 
I don't think that the part you show on the pic is for draining, it looks like it's welded to me. So i wouldn't temper with this. The thing you would be looking for should look like the marked area in the pic i attached. View attachment 22961

That is definitely not the drain for the tank. That is the pressure valve for incase the pressure switch does not turn off and the tank gets overfilled.

The previous image is where the valve is. Just have a look and see if it can be removed.
 
Ok unless I am totally wrong, the red circled valve is actually the relief valve, not the drain, unless of course your manual says otherwise. Every safety relief for pneumatics I deal with, and I work with it in an industrial atmosphere, has a pull ring for testing. The fitting on the bottom that was shown has a rubber o ring or seal. Again I would let all he air out with a hose or something and check the fitting on the bottom. If it has a copper disc the it is a safety .


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Sax pull that out with the ring, tank full and and It would probably be a good idea to have ear plugs in LOL Wayne is correct with both his fine piece of art and the relief valve.. maybe you could paint one of those also?? (as well as the others about the valve)
PS I replaced all of mine (7) with these>http://www.amazon.com/BOSTITCH-Ballvalve-Compressor-Drain-Valve/dp/B001PH9EGI way easir to drain especially the larger compressors PSS i didnt pay that much
 
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Thanks again Wayne. I already read my manual and it does refer to the red thing as a safety valve (it doesn't say anything about the bolt at bottom and did not include any instructions for draining the tank). I know that I have to drain the tank after every use. Plus, My airbrush is spitting water randomly as I practice. I am just going to try the bolt at the bottom. Maybe it is a older version of the compressor and I need to purchase a more convenient piece. I will do what Ko did and purchase one of those and an extra moisture trap.

Thanks everyone!
 
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I do not drain mine every time, try it once a week, if you hardly get any water, lengthen the interval. Then see what the results are. I do mine about once a month.


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Thanks again Wayne. I already read my manual and it does refer to the red thing as a safety valve (it doesn't say anything about the bolt at bottom and did not include any instructions for draining the tank). I know that I have to drain the tank after every use. I am just going to try the bolt at the bottom. Maybe it is a older version of the compressor or someone wants me to purchase a more convenient piece. I will do what Ko did and purchase one of those.

Thanks everyone!

Hi yavniella, please let us know if it works unscrewing the bolt at the bottom to drain the tank. It looks like it should. I have the same kind of bolt at the bottom of my old compressor air tank but I have never dared undo it. My compressor manual also did not say how to drain the air tank or what that bolt was for either so I am very curious.
Cheers Mel
 
Will do. I have to try it because my airbrush is randomly spitting water. If it is not that then possibly I need an additional moisture trap. I have already drained the moisture trap on the compressor and it did not work.
 
Finally drained the tank

Hi yavniella, please let us know if it works unscrewing the bolt at the bottom to drain the tank. It looks like it should. I have the same kind of bolt at the bottom of my old compressor air tank but I have never dared undo it. My compressor manual also did not say how to drain the air tank or what that bolt was for either so I am very curious.
Cheers Mel


I drained the tank by unscrewing the thing at the bottom. It really needed to be drained! There was sooo much water and it was also rustey colored. I hope I did not to take to long to do it. I've done it more than once and there was nothing coming out, so I can do it less often.
 
I would recommend though next couple of time you drain it to take that O-ring off and try to find a replacement. In that pic you had that poor thing has seen the best of it's days already and needs to be replaced.
 
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