compressor motor switch

[37chief]

Mt compressor has a lagge line from the comressor to the tank. Also a 1/4 inch line to the switch. When the compressor gets to 120 pressure it shuts off, and the 1/4 inch line to a valve on the switch starts leaking. I plugged the 1/4 line to the switch and the compressor shuts off at 120 lbs, and starts agin at 90. The switch seams t work without the 1/4 in line hooked up. What is the purpose of the 1/4 in lint to the switch? Stan

 

[wore out]

Mt compressor has a lagge line from the comressor to the tank. Also a 1/4 inch line to the switch. When the compressor gets to 120 pressure it shuts off, and the 1/4 inch line to a valve on the switch starts leaking. I plugged the 1/4 line to the switch and the compressor shuts off at 120 lbs, and starts agin at 90. The switch seams t work without the 1/4 in line hooked up. What is the purpose of the 1/4 in lint to the switch? Stan

The little line and the valve on the pressure switch "unload" the compressor and line to the tank check valve so the motor doesn't have to start the compressor against pressure.

The symptom of leaking air you are seeing indicates that the tank check valve is not holding pressure/is leaking.