central air with baseboard heating system

The house is heated with a hot water system...three zones: one for first floor; one for second floor; and third for hot water heater. Central air was installed with air handler in the hallway at the top of the stairs (center hall colonial). Because the thermostat is at the top of the stairs and warm air rises, the second floor does not get adequate heat. There are two bedrooms to the left of the stairs and two bedroom to the right with a hall bath in the middle. What would be the best location for the thermostat? It used to be in the master bedroom, the largest room to the right of the stairs, but when the new CA unit was installed, the techs moved the thermostat to the open space at the top of the stairs.

 

Welcome to the forums.

It needs to be in the room where you want it to read.
Why was it moved out of the bedroom ??