20 Most Recent Craftsman 3 gal. Air Compressor, 1 hp, Tank - Page 8 Questions & Answers

Start Capacitor isn't working

Check the condition of the piston rings, then the reed valves.

The regulator knob may not be letting any air past it. It's the only valve that controls the amount of air pressure is let into the hose.

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Did you try to insert a nipple into it ... maybe something has to be inserted to release it. Maybe try to tap it lightly to see if it will pop loose? Be careful not to mess anything up in case you need to return it. Since you just bought it I would check with the store or manufacturer. They can tell you if it should be back or not ... if not I would return it. If you do not want to deal with returning it just replace the coupling with a good one.