I have a 16 y/o Water Furnace Intellizone 17P519A01 (serving 3 zones and controlling an AirZone vacuum damper system) and want to upgrade my thermostat system to the Honeywell Prestige IAQ. I have a couple of options and want to know if anyone has any experience with this. Option 1. Completely replace the Intellizone system (since I will need to replace the Water Furnace geothermal system soon anyway) with the Honeywell Prestige IAQ thermostats linked by equipment interface modules to a zone controller (HZ432K). There are a couple of problems with this in that Honeywell indicates that the HZ432K is obsolete and being replaced, but they won't say by what, and they won't give me information about possible use of the HZ432K since I am not a contractor. Also, I don't know if the HZ432K outputs to the dampers will interface with the AirZone unit. Option 2. I can keep the Water Furnace zone controller since I know it works with the AirZone damper system and then just use a single Honeywell Prestige IAQ thermostat to replace one of the current Water Furnace thermostats. The thermostat is a 2-wire model that would then use the equipment interface module to connect to the Water Furnace Intellizone board in place of the old thermostat. The thermostat is a 24VAC model and output amps range from 0.5 - 1.0, but I don't have any idea what the Intellizone board input ranges are. Maybe this is an industry standard, but I don't know. If this option worked, I could potentially then continue to use the Intellizone controller to serve as the input to my next geothermal system. Any advice or information would be greatly appreciated.