If you need to keep your 2 buttons, the cheapest way that will work safely is to add 1, DPDT control relay.
1.) Wire "L" or "Hi" to N.C. "OFF" button to N.O. "ON" Button to relay coil to OLs to "N" or "Lo"
2.) Wire relay N.O. contact in parallel with the "ON" button. (Holding contact for the control ckt.)
3.) Wire "L" or "Hi" to other N.O. relay contact to P-switch with differential to contactor coil. (Normal compressor cycling when control circuit is active.
Add any E-stop switches to Line 1. Just about any starter assembly should have the volume to add a control relay. I can do the ladders up on CADD if you want.
Joe
