We have a Hydro Air system with 2 separate air handlers, one in the basement for the first floor and one in the attic for the second floor. As the temperature was dropping last few days, I turn on the heat for both the first and second floor and noticed that only the first floor was pumping out the hot air and the second floor was pumping out the cold air. I went up to the attic and noticed that the air handler isn’t getting hot water, pipe was cold. Then I went down to the basement where the oil boiler was and I felt a hot water in the pipe. Apparently the hot water is not getting to the air handler in the attic. Any suggestions? Thank you!