# Should air be flowing while filling air compressor?



## JGalovin (Mar 14, 2011)

I recently inherited an air compressor and I'm not sure that it is working right. When the compressor is running, there is air coming out of the silver tube where it meets the top of the tank. (see attached photo) Should I have air coming out while the tank is filling? Also, the silver tube seems to be kind of loose feeling. The tank holds the pressure without leaking but seems to vent while filling. Is this normal? Also, the silver pipe gets quite hot while running. Not sure if this is normal either. Can someone please let me know what I should expect? Much thanks.


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## Jackofall1 (Dec 5, 2010)

Hi and welcome JGalovin, to the best darn DIY'r site on the web.

Tube gets hot ----very normal, don't touch thats how hot it gets!

Tube leaking while filling tank --- not normal;

Tube loose feeling -- not normal

Tighten compression nut at connection on tank (top nut) and this should remedy the problem.

Mark


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## JGalovin (Mar 14, 2011)

Thanks for your help Mark. I tightened the compression nut pretty tight and it still seems to leak while filling. Any other suggestions? What about putting a little plumbers tape around the connection to help seal?


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## Jackofall1 (Dec 5, 2010)

Question, you say its leaking, can you physically feel it? or just hear it.

If the latter, its the sound of the air going into the tank.

A word of caution-- Compressed air is one of the most unseen dangers. The stored potential energy in CA is deadly, please be careful when using and working with CA.

Mark


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## rditz (Jan 6, 2011)

undo the nut completely and slide it away from the tank. check the flare to see if there are any cracks or chips in the flare, this may be where your air is leaking from.. if the air is leaking between the tube and the nut, then plumbing tape will not resolve your issue. if the air is coming from between the nut and the tank, then try some tape and see whether it fixes the leak.

agreed, the tube should get hot because of the heat generated by compressing the air.


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## Jackofall1 (Dec 5, 2010)

I really can't see how air could be leaking while the compressor is running but not leaking when the compressor stops and there is pressure in the tank.

Mark


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## JGalovin (Mar 14, 2011)

I'm with you there Mark. I thought the same thing. Air is not leaking after the motor shuts off. Weird.


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## rditz (Jan 6, 2011)

is it possible that there is a check valve at the tank and once the pressure switch has shut off the compressor, the check valve prevents air from escaping the tank??

rod


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## DexterII (Jul 14, 2010)

The arrowhead is a bit in the way, but I believe that the line threads onto the check valve, which in turn threads into the tank. Repair the connection there, as Mark and rditz said, but do not remove the check valve if there is any pressure in the tank. In fact, the safest thing would be to drain the tank pressure completely before doing anything. Since you said that the tank is holding pressure, there is no reason to remove the check valve; you only want to remove the nut that attaches to it.


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## JGalovin (Mar 14, 2011)

I assume that there is a check-valve and it seems to be working. Air only leaks while the tank is being filled. It has to be a problem with the tube and where it meets the compression nut.


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## Thurman (Feb 9, 2009)

The "Silver" colored piping gets hot because new, compressed air is hot and is passed through this pipe to the tank of the compressor---normal for that. The fitting the silver piping (nickle coated copper) goes to has a compression fitting in it, not a flared fitting. The "ferrule" of the compression fitting has been tightened too tight and probably has created a small crack in the piping where the ferrule fits onto the piping. Removing the nut will show the ferrule ( a little ring that fits onto the piping) compressed into the copper piping. YES, there is a check valve within the fitting that screws into the tank itself, and the silver piping connects to. This is why he can hear the air escaping when the unit is running, and no air leaking when the unit is shut down. This also indicates that the check valve is holding very well--that's good. The proper repair would be to replace the piping from the compressor head to the check valve adapter fitting. This would require the silver colored piping, bent properly, a new ferrule and nut for the compressor head, and an new ferrule and nut for the check valve/adapter. A DIY job? Yes, with patience.


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