We have problems with our HVAC zone system. There is one outside 5 ton unit and two zones, main house with its thermostat and the smaller upstairs zone 2 with it's own thermostat.
The problem has been the dampers was sticking and causing the whole unit to freeze up in ice, the repairman cam yesterday and put in new damper, the old one looked warped. he also replaced the board inside the unit. Now he says the unit gets a signal from the thermostat but will no obey it. he plan to replace the board on the wall today. This unit has up on damper motor and fried one inside board in the past. No one seem to no how to fix it. I did put on new thermostats that said OK for zone last year and wonder if that is the problem but HVAC guy says no but I am no so sure. Any suggestions for when he come s back today?