Air Compressor leaking Water out top?

RTR

Well-known Member
I was sitting about a foot in front of the air compressor working on a little Cub Cadet Mower tractor when i heard a chirping/bubbling noise. I turned around to see water coming out the top small soft line of the air compressor as marked in the picture. That line ties into the very top of the tank. Should I be concerned? Maybe that line got loose over the years? I don't want to mess with it until I asked. The compressor was bought new and installed in 1992.
mvphoto26926.jpg
 
That is the air release line. When the pressure switch gets to the
correct pressure it shuts off your machine. That line goes to a little
unloader valve on the switch it self. When your compressor shuts off
you should hear a little Pusssh from that area. The water is
condensate from your machine making air for you. The line might be
cracking, or the little valve on the switch is going bad. You can
replace that line or you might need a new on/off switch. By the way,
that plastic line uses special little fittings that keep the tube from
being crushed. If you get into this i can list the little parts you
will need. Sounds like you need to drain your compressor more often.
 
Is the little line connected to the tank or to the fitting that connects the line from the compressor
head? If it connects directly to the tank then it's the pressure sensing line, not the bleed off line.
Either way, you need to fix it and drain the tank. I can't believe the tank is full of water, but it's
possible. I drain my tank once a year, when I blow out the sprinklers, and only get a few oz.
 
If you keep the tank drained I wouldn't be concerned. They leak water all over including the rubber air hoses. Sometimes even nail guns will spit water at you.
 
The unloader line should be installed between the switch and inlet check valve on the tank. Once the compressor kicks off a small lever on the pressure switch opens a valve to release the pressure between the compressor head itself and the switch. This allows the compressor to start back up with no pressure. Without a bleeder the motor would have a very hard time starting and would not last long.

In the winter you have a lot of condensation in a compressor due to cold air hitting hot parts. You need to drain the system more often and keep the intake air filter clean. If it does not have an air filter, one should be installed.
 

I hate to say this, but the compressor has been drained 2 times in the past 26 years. It has a petcock valve from the factory and around 2 years ago I realized it was supposed to be drained often and tried to do so. With the valve approx 1.5 inches from the floor it was hard to get to and seemed finicky and stuck. I was worried to turn it too much in fear I would break it and keep me from using the compressor. With the plumbing installed it makes it tough to raise the tank to install a ball valve and extension. I got it open them and let it drain til it stopped. Not sure if it completely drained or not. The las time before that my grandfather said was in the 1990s and he just left it barely cracked since he shut Power off each time he left shop. This compressor has worked flawless for the past 26 years with he exception of a pressure switch replacement and changing the oil in the compressor once or twice.
 
Look at it this way... when you start a compressor with an empty air tank, MANY cubic feet of atmospheric pressure air get smooshed/packed into that tank, along with any humidity/water vapor it contains.

So, over time, most of the humidity/moisture in the air taken in by the compressor turns to non-compressible liquid water that builds up in the bottom of the tank until it's drained.

The more hours of use the compressor "sees"/runs/takes in air over time and the greater the surrounding humidity is the more water builds up.
 
It's possible that when you opened the valve or pulled the plug it didn't drain all out. The bottom of the tank can accumulate rust and dirt. I delt with that
last time I drained mine. I had to stick a wire up in the hole to dislodge all the crap that has accumulated in the bottom of the tank. Yes, I know that means I
don't drain it enough. But leaking out of the top doesn't necessarily mean it's full of water. Occasionally mine will bubble water out of the top line also, I
think that's just from condensation.
 
Hello RTR,

That small line is the pressure switch line. Goes to the to the top of the tank, where the unloader valve is. It should be a 1/4 in line and should be tight. It has a furrel on the line as a seal. Probably cracked if it was bumped. Try to get it tight, It may be just loose. It should be tight, so the pressure switch is able to cycle the compressor properly,

Guido.
 
(quoted from post at 05:45:37 11/19/18) Hello RTR,

That small line is the pressure switch line. Goes to the to the top of the tank, where the unloader valve is. It should be a 1/4 in line and should be tight. It has a furrel on the line as a seal. Probably cracked if it was bumped. Try to get it tight, It may be just loose. It should be tight, so the pressure switch is able to cycle the compressor properly,

Guido.

Thank you all for the suggestions. I will check it all out but I'm wanting to break down and do some maintenance on he compressor. It deserves it. I will try to raise the compressor and put a pipe extension and ball Valve on it.

Any suggestions as to any maintence besides steam cleaning the fins on the compressor, changing the oil, replacing air filter, and draining the water? I'll leave the belts alone since they are still working.
 
If you are going to steam clean the pump do it before you change the oil. There is a vent on the pump which you could get water in the oil reservoir. If you don't drain the tank of condensation on a regular basis you might consider getting an automatic drain valve to put on a tank. It uses a timer to automatically drain the water out of the tank so you don't have to think about it that often. https://www.amazon.com/CNBTR-Automatic-Direct-Acting-Electronic-Compressor/dp/B01DIXZINO/ref=asc_df_B01DIXZINO/?tag=hyprod-20&linkCode=df0&hvadid=241989147482&hvpos=1o2&hvnetw=g&hvrand=1666616115997905395&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1026339&hvtargid=pla-476667043675&psc=1
 

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