I think this control might be what your looking for to control the two furnacesand if you call them maybe they could do all three for you
The thermostat you are suggesting is a two stage thermostat. We currently have two LR1620's and one that looks just like a standard round honeywell. I could only find the this number: T87F2808 2 8030. I did not take it apart other than removing the ring. They are heating and cooling thermostats. From other research I have done, I think they are single stage thermostats.
The furnaces are twinned to run as a single unit. They both run, or neither one runs. We have three sets of twinned furnaces. I have tried to get several local HVAC guys to come look, buy our area is in a huge growth spurt, and no one we trust has the time for a little job.
Are our current thermostats single stage, or are they two stage?
I live in Gillette, WY. I do not believe we have any Johnson Controls here. I will check. I know I have seen them here, but they are from out of state. Our mild weather heaters are usually to put on another layer, or take one off. I was under the impression you have to have a two stage furnace to have a two stage thermostat. From what you have said, I am assuming this is a false assumption.
Thank you so much for your help. Hope you have a blessed day!
Any good Honeywell Thermostat will work
http://customer.honeywell.com/techlit/pdf/67-0000s/67-5099.pdf I like this better