I'm new to this site and I have a question that none seems to be able to answer. I have a dual zone heat/ac system in my 2100 sqft 2 story home. Recently my heater has been short cycling, but only when the heat is turned on up stairs. (Downstairs has been working great). When I say short cycling I mean I set the heat up stairs to 69 with the current temp 64. The heater will turn on and blow heat until it reaches 1 degree higher, then it shuts off and restarts. It will continue to do that until it reaches the set temp. So from 64 to 69 it shuts down and recycles 5 times.
I have had a tech out who checked my zone control board and said it was bad. I replaced the board and get the same results. I have also tried replacing the electronic termostat with no luck. Filter is new and vents are up on the walls and clear.
ANy suggestions? I'm out of ideas
Thank you very nuch for taking the time to read this post.