I have a 13 gallon, 4HP, Campbell Hausfield air compressor that I have trouble with. It will start and run until it reaches the cutoff pressure, at which it blows the circuit breaker. I bypassed cutoff switch and wired it straight to the wall oulet to test the compressor and motor, and it ran fine. I reinstalled the pressure switch and ran it again but stopped it before it reached the cutoff point. When I tried to start it again, the unit dragged like it was under a large load and tripped the breaker. I did this again but before trying to restart, I bleed the air off and it starts fine, repeatedly.
That is when I ordered the CHCW210100SJ pressure switch.
Now I have the new switch on and I have the same problem. Do I have something else wrong or did I receive a new-defective switch assembly?

1 FURNAS TO CONDOR P/S part # CHCW210100SJ $32.54
This is a standard 115 volt, small compressor. It has been running very well for two years on a standard garage outlet. I have replaced the breaker with a 20amp, checked all connections. REMEMBER, if I drain the air down it will start just fine.