I just spoke to a trane salesperson who said that the xv90 won't work "right" with zoning ... in effect you won't get
variable speeds out of the unit with all zones calling. He says when it gets installed w/zoning something gets wired that basically makes the furnance operate in single speed? This makes no sense to me? I have 2 other proposals that recommend the xv90 and say it works great with zoning. Now I am really confused?