Question about Craftsman 3 gal. Air Compressor, 1.5 hp, Horizontal k

2 Answers

Leaking Pressure Switch

My compressor suddenly developed a leak in the pressure switch. This is an "L" shaped switch easily visible on the compressor. However, when I went to Sears and showed them the part from my compressor and the part as it looked installed on the same compressor in the store they said they couldn't find the part. They recommended that I start ordering pieces paying for shipping and return shipping until I get the right piece. The part does not show up on their parts breakdown illustrations or lists so they don't know what to do. Can anyone help? Thanks!!

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  • riveroaks05 Feb 19, 2009

    can i just block off the 1/4 inch pressure wswitch line at the check valve and still be safe to use the compressor?

  • Anonymous Mar 11, 2009

    I believe that I was wrong in my initial wording of the problem. My leak is not in the pressure switch but instead in the little L shaped brass device that is connected to the pressure switch. This piece has a small pin that extends to turn on the compressor when, I guess the pressure in the tank drops below a certain point. The leak is in that small piece and it does not show up on the sears schematic. I can't even find the number or name of this piece on the Sears website and when I show the people at Sears my faulty piece and point to the same piece on the compressor in the store they say that they can't find this piece. I can't seem to locate the piece at Grainger because I'm not sure what this piece is called so I don't no really what to look for. Thanks for all of the above help but my compressor is still on the blink!



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You can go on sears web site in there parts replacement with your model # and it will show a full schematic

Posted on Mar 10, 2009

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Leaks at the pressure switch are usually associated with the unloader valve due to leaking checkvalve at the tank. To determine the faulty part requires a couple of tests. Run compressor till it shuts off and is full of air then unplug the unit. Spray soapy water or (windex) around the base of the pressure switch to find where air is leaking from. There is a rubber diaphragm incorporated into the base of the pressure switch that may develop leaks. If the base is leaking check for loose parts or screws. If the air is leaking from a valve that looks like a tire stem, then leak is a result of faulty check valve in tank. Follow the 1/4 tubing that is connected to the pressure switch down to the brass valve at the tank. This brass valve is not holding tank pressure causing leak at the pressure switch. Replace as neccessary. The pressure switch is expensive. Do not replace unless you have looked at checkvalve. A universal pressue switch can be and should be used to same money. The check valve need not be replaced with exact replacement. Universal parts are available at . Just match tubing and thread sizes and pressure range for the switch. Good Luck on your project and email if you have more questions. Please wait for the soapy water or windex to dry before you plug in the unit.

Posted on Feb 13, 2009


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