How To Install A New Thermostat How To Install A New Thermostat

What You'll Need
Electrical pliers
Wire strippers
Drywall anchors
Torpedo level

A new digital thermostat will help you save energy in your home by controlling your furnace or electric heating system more accurately. Follow these directions to remove the old thermostat and install a new one to get the best performance from your furnace.



Step 1: Locate All the Old Thermostats in Your Home

Check the locations of all the thermostats in your home. There may be just one on the main floor, or each floor or bedroom may have its own. Remove and replace all the thermostats at the same time so the heating in each area of your home is controlled accurately.


Step 2: Choose the Correct Type of New Thermostat

Most gas and oil furnaces use a low-voltage 24V thermostat with a transformer mounted near the furnace to reduce the voltage from 120 volts. Most electric heating systems use a line voltage thermostat system with thicker wiring than low-voltage thermostats.


Step 3: Remove the Old Thermostats

Turn off the power supply to the furnace and turn all electric heat thermostats to the "Off" setting. Disconnect the circuit breaker for the furnace or electric system. Remove the mounting plate holding the thermostat to the wall, and gently pull the wires out of the wall. Draw a sketch or take a digital photo of the wire connections before detaching them from the thermostat. Remove the mounting plate from the back of the thermostat.


Step 4: Install the New Mounting Plate

Insert the mounting plate into the wall space occupied by the old plate. Pull the wires through the mounting plate hole gently, without bending or crimping them. Mark 2 screw holes on the wall at the top of the mounting plate, to fasten it to the wall. Check the mounting plate is level with a torpedo level. Insert and partly tighten the screws into the marked screw holes. Check once more for levelness, and then tighten the screws snugly. Use drywall anchors to hold the mounting plate and thermostat if it is heavier and larger than the old model.


Step 5: Connect the Thermostat Wiring

Match the wires by label, shape or size to the new thermostat. Follow the wiring diagram supplied in the manufacturer's instructions. Tighten the terminal screw holders snugly, so they hold firmly but do not crimp the wire or crack the insulation. Push extra wiring back into the wall and align the thermostat with the mounting plate.


Step 6: Attach the Thermostat Unit to the Wall

Push the new thermostat cover into the mounting plate. Make sure the electrical connections remain correctly aligned. Restore the power to the furnace or electric heat system, and test the thermostat at various settings.


Step 7: If the New Thermostat Does Not Work Properly

If the thermostat is not operating properly, disconnect the power supply to the furnace or electric heater, and inspect the wiring to ensure all the wires are connected to the correct terminals. Adjust the tightness of the wire terminals so they do not cut the wire. Be sure that the wires are not crimped between the mounting plate and the thermostat cover.


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