EWC Controls Forum

I currently have a ST-2D control, Gas furnace / AC / 2 Zones. I want to add another Zone possibly 2 for a total of 4 zones.

I have another ST-2D Contol, can I use the "Additional Zone Panel" on both panels and use 2x(ST-2D) controls to control 4 zones? Help would be appriciated.

Any negatives on ...