Kobalt Tank emptying

by Glenn
(Moss Point, MS )

Compressor is a Kobalt 30 gal. vertical tank.

Everything I read says bad relief valve, but has to be something else or reason.

Compressor has run faithfully for about 5 years.

Started loosing air around unloader valve.

Replaced pressure switch which had a new unloader valve. Would still loose air but not all the time.

In the past few days it started leaking air continuously, and it seems to start leaking as soon as the pump starts.

I read it should be relief valve. Replaced with an old one I had laying around that did work when I removed it (compressor was destroyed in hurricane katrina). Still compressor would pump to cut off and air would drain from unloader valve.

I then purchased a new check valve. Made no difference. Will pump to cut off. After it shuts off it all of the air in the tank will leak out.

If I use the pressure switch cut off switch or unplug it, the air continues to leak until 0 psi pressure.

This has me pulling my hair out, as it is my main supply in a small furniture shop where most tools are air drive. Can you give me any solution to get it back up and running. Or give me other troubleshooting branches I can run down.

Thank you

Comments for Kobalt Tank emptying

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Aug 29, 2017
Kobalt Tank emptying
by: Bill

You are welcome, though it would seem that you figured it out all by yourself.

Glad it's back to snuff.

Aug 28, 2017
Finally Done
by: Glenn

Hey Mr. Bill,
I received the new tank check valve, replaced the old and the compressor is operating as it should. Was a bugger to get changed. Check was between the pump and the motor. To get to it with a wrench would have had to remove either the pump or motor. Other option was a socket but the unloader fitting kept that from happening. Had to take a adjustable wrench and break the hose nib off of the 90 deg. brass unloader fitting. Once that was off I could remove the rest of the fitting, and get a socket on the check valve. Had to purchase a 1/8"mpt x 1/4" compression 90 deg fitting at my local hardware store, and back to good as new, with a couple spare pressure switches and switch check valves. Makes for a easier job when you change the right part.
Thanks for you help.

Aug 18, 2017
Pressure switch
by: Bill

Glad you found the problem, Glenn.

Also puzzled by the fact that your Kobalt has a check valve at the pressure switch. That's news to me.

There is a valve at the pressure switch, and typically that's the unloader valve or bleeder valve that allows air over the pump to escape when the compressor stops.

Anyway, if your Kobalt is fixed, that's good news.

Aug 18, 2017
Problem Found?
by: Glenn

I think I have found my problem. I have two check valves. One on the pressure switch and one on the tank itself. I was stumped how the little rinky dink one on the pressure switch was letting air escape from the unloader. While ordering another check valve for the pressure switch, I noticed there was a fitting under the tube that went to the tank and low and behold it was a check valve. I started putting 2 and 2 together and come to the realization I was a moron. Wife been telling me for years, guess I'm gona have to start listing to her....Naaa!
I have one ordered and will let you know the outcome.
Thank you for your help.

Aug 17, 2017
by: Doug in s.d.ca.

Knowing the actual model number would be helpful.

Are you certain the new check valve is installed correctly?

And the problem IS the check valve, for sure.

Aug 17, 2017
Soapy water to find leaks
by: Neil

Make a spray bottle of water and dish soap.
Spray it where you think the air is coming from.

Aug 16, 2017
Kobalt leaking
by: Bill

Take a moment to think about, when the compressor is stopped, and air is leaking out of the unloader valve / pressure switch, where that air has to be coming from?

It has to be coming from the tank, right?

If it's coming from the tank, and there isn't a hole in the tank under the pressure switch to allow air to bleed out, then the only place the leaking air can be coming from is the tank, and if that's the case, it MUST be bleeding past the tank check valve.

So, you may have a new tank check valve, but unless the tank itself has a hole in it, that new check valve isn't working.

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