EWC Controls Forum

I want to upgrade my old control panel (EWC ST-2D) to a modern unit (EWC NCM300) with modern thermostats (Honeywell RTH9580WF). The 24V, Zone2, and Zone1 motor wiring seems straightforward, but the system wiring does not seem as easy. I currently have only a Y, W, G, and R wire connected to the ...