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Air compressor HELP!

6

69mstng

Member
I have a craftsman 33 gal 6hp air compressor. It only pumps up to 20lbs and then shuts off. I replaced the pressure switch today with a new one and it still does the same thing. Does any one know what the problem could be???
 
:wstup

Has to be the switch. Pop that cover off and watch when it makes pressure contact. See if something is adjustable.
 
There is a little black plastic screw that i have been adjusting but it did not seem to change any thing. Here is a picture of the switch. Any ideas?
 
Should be instructions on the inside of the cover as to how to adjust. It should have two adjustments. One changes the high pressure cut off and the other changes the low pressure cut on...or the difference between the two... It looks like a typical pressure switch used on air and water pump systems. Might check on line for exact directions.
 
Does the motor trip out when it stops or is it just stopping as if it has reached pressure? You may have a bad check valve allowing the tank pressure to prevent the pump from operating.
 
Some times when you turn it on it will start pumping up real fast then after a few seconds or so it starts kind of straining its self to get there. Then it will stop pumping and try to start pumping again real slow for a second or so and shut off. Can you decribe were the check valve might be?
 
It's on the outlet side of your pump. The compressed air passes through it to get to the pump. It acts as a one way valve to allow the compressed air out but doesn't allow any air (pressure) back in. It doesn't take much head pressure to stop the pump from operating.

By your last description of the problem, I'm betting we've found your culprit.
 
The valve is probably where the pump line attaches to the tank (in-tank design). Remove the line and you should be able to see the valve. Most likely, you'll need to replace it. Sometimes it's dirty and can be cleaned. really depends on the age.
 
Thank you all so much for your help. I just got the check valve out. The compressor is probably 10 to 15 years old so it is probably best just to buy a new valve. Thanks again! :coo
 
A question, is the collection tank full of water. Have you drained it lately, this could be the cause as it senses no capacity.
Just a thought as it happened to me.
Ash
 
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