I've got a Carrier Infinity Zone Controller with four zones in a 3000 sq ft, 2 story, open floorplan house. A/C is a 5/3-ton 2-stage unit and heat is gas all driven by a variable speed blower. Our configuration won't allow for a bypass duct so there is a designated dump zone to handle excess capacity. My problem is that I'm getting constant errors that are apparently coming from the zone board as we just had the furnace mainboard replaced for a cool $1k. Replacing the zone board is going to set me back almost as much and I'd like to step up to an internet connected thermostat but that's another $1K for the Carrier version.

I'd like to scrap the Carrier system and get a ZoneFirst board with Nest thermostats which will add learning in addition to internet connectivity. Talking with both Nest and ZoneFirst I discovered that I have to replace the dampers as well because the ZoneFirst board won't operate without a bypass duct and fail-closed dampers.

Does anyone have experience with this kind of swap-out and would you share your thoughts? Are there other zone controllers that will work more seamlessly with my existing dampers? Am I completely mad and should I abandon this project and just accept being married to Carrier for another 15 - 20 years?