After installing the RTH3100C, you can enjoy maintaining a comfortable temperature within your home, even when the snow is falling. The RTH3100C by Honeywell is a non-programmable digital thermostat with features including a large backlit display, displays of both room temperature and temperature setting and one-touch temperature controls. This thermostat is only for use with heat pumps with auxiliary heat. Safety features include emergency and auxiliary heat indicators; temperature control within +/- 1-degree Fahrenheit and battery power that retains memory during power outages. Most thermostats have similar wiring, easing the installation process for the installer.

Enjoy your inside temperatures even when the outside is snow-covered or cold.


Step 1

Cut the power to your heating and cooling system (your previous thermostat). Use your breaker box to do this. Disconnecting the power ensures your safety when disconnecting the wires from the previous thermostat and connecting them to your RTH3100C.

Step 2

Remove the entire old thermostat except for the wall/baseplate. Leave the wires connected to the terminals on the old baseplate.

Step 3

Remove and mark each wire, doing this one at a time to avoid wire confusion, with the included wire labels. If you do not have the labels, use small adhesive labels and write the wire's corresponding terminal letter on it with a pen or marker.

Step 4

Remove the old wall plate once the wires are all marked and disconnected from the terminals. Hold onto the wires to prevent them from slipping into the hole in the wall. Wrap them around a pencil if the hole is too large and the wires may slip.

Wiring the RTH3100C

Step 5

Remove the wall plate from the RTH3100C by pulling where indicated on the bottom.

Step 6

Hold the wall plate against the wall and pull the wires gently through the opening. Mark the screw holes on the wall plate on the wall using a pencil.

Step 7

Drill pilot holes for the drywall anchors where you marked the holes, then install the drywall anchors. Mount the wall plate on the wall using screws.

Step 8

Match the labeled wires to the corresponding terminals on the RTH3100C. (See Tips for additional information regarding wiring.)

Step 9

Install two new AA alkaline batteries in the back of your RTH3100C. Push the thermostat back onto the wall plate. You can now turn the power back on.