Compressor stops working

[ThomaStudios]

I have a CH compressor with a 20 gallon tank, 230volt. I've had it for 16 years and no issues, until today. I noticed I wasn't getting much air pressure and in looking at the regulator meter it was only showing about 20 psi. Additionally, the gauge on the tank also showed about 20 psi.
The switch is always in the Auto position, and turning it off and back on again did zip. I went over to the breaker panel and sure enough, the breaker had tripped at some point. When turning it back on and then turning on the compressor, all I get is a very loud hum from the motor. Something is definitely awry.

Any suggestions from the knowledge conglomerate here?

[daddo]

When was the last time you changed the oil in the compressor?

[AlanBienlein]

Sounds like the reed valves gave up the ghost.

[BloomingtonMike]

Unloader valve or check valve or start cap.

http://www.about-air-compressors.com/hum...essor.html

[iamrfixit]

Drain all the air from the tank and try again to see if it will start, if it does it could be as simple as the check valve between the tank and compressor. The check valve keeps the stored air in the tank. If it sticks open the pressure gets back against the compressor and can stall the compressor on startup. Without pressure in the tank it may start fine, as long as the motor did not get damaged.

Could also be the unloader. This valve, usually located on the pressure switch dumps off the pressure between the check valve and the compressor each time the psi switch kicks the motor off.

Either of these are likely possibilities, or it could just be that the motor went bad. Unfortunately, the motor might have been damaged if it did try to start under load.

Another thing to check is if you actually have 240 volt to the outlet where it is plugged in. To do this you must use a multimeter to test between the two hot leads. It is possible to have power, but not the full 240 volts to start the motor. A 240 motor trying to run on 120v runs slow and hot, and may not start the load correctly.

[JIMB49]

+1 for reed valve