I am trying to build a control system for a 3 stop dumbwaiter. I would like to use latching relays and magnetic contacts for simplicity. The lift motor is a 120V reversible hoist that draws 7A. The wall switches I have are Leviton LVS-003. I need help with the circuitry design and sourcing of materials. The open door safety and the slack cable safety are in place, as is a 24V DC power supply for the relays. There are basically three circuits 1 to 2 / 2 to 1, 1 to 3 / 3 to 1, and 2 to 3 / 3 to 2 . If it were only two floors it would be quite simple. My difficulty is how to bypass the middle floor when needed. I want to stay away from electronics that because of my remote location would be unserviceable. Just simple relays and contacts. Can anyone help with a schematic and parts list. Thanks . BOB S.