07-05-2021, 04:49 PM
I think you need a solenoid that is normally open & closes when energized so the air system can build pressure when the compressor comes on. Then when the compressor shuts off the solenoid is deenergized, opens and releases the water from the air dryer bowl & the head pressure on the compressor.
Steve Bare
1999 Newell 2 slide #531