I've a Carrier zone thermostat and want to remove it from the wall far enough to install some insulation padding and radiant barrier between it and the wall. I cannot figure how the plastic casing comes apart to get at the mounting base.

This is the zone thermostat, which is smaller than the main thermostat. It looks like a standard Carrier non-programmable thermostat.

Ralph

No model #, will do my best here. Are there hinges on the left side of the thermostat? If so, the thermostat swings/snaps into the right side of the sub-base. Look for a seam where the two parts separate.

Thanks, KC13.

Found the hinges on the left. The front just swung out, attaching to the lead wires with some little metal prongs that automatically came out when it was swung open.

Swinging the front out of the way gave me access to the 2 screws attaching it to the wall. Found that all the insulation had been mashed out of the way when they put the thermostat in. I cut off a little bit of insulation and stuffed it into the wall cavity. The outside wall may have been giving an incorrectly low reading on the thermostat, making it kick the whole house unit on line in really cold weather that we had this last month.

I also attached a couple of those electrical box insulation pads to the back of the unit before screwing it back into place.

Ralph

Exterior walls are not recommended locations for thermostat installation, for just that reason. If possible, you would be well-served by relocating it to an interior wall, avoiding direct sunlight and supply air discharge.