I inspected a 4 year old home this week that had a Geo unit installed unlike any I have inspected before.
It was a two story one system unit with supply and returns from the ceiling.
Both levels had their own thermostats that could activate the cooling or heating mode separate of each other or both call for A/C or heat at the same time. Needless to say one stat could not be in heat and the other stat in cool both stats have to be in the same mode. There were 24 volt controlled dampers in the supply duct that would open and close according to what stat was calling. If the down stairs was calling for cooling the upstairs dampers would go closed and VS if the upstairs was calling and not the down stairs and both would open if both stats were calling at the same time.
This unit had two vertical loops one for each level of the home that were drilled to 200 feet in depth. This was all controlled with an electronic logic board. I liked this system. I was just wondering how many inspectors have ran into this type of system any comments.