The functionality of your thermostat is vital to winter survival. It is highly sensitive and can be the source of many problems in your heating and cooling system. If the calibration of your thermostat is inaccurate, it may be time to replace it.
You will need a screwdriver, a utility knife, a replacement thermostat, tape and a level.
Step 1: You first need to remove the old thermostat by taking the face plate off of the old unit and looking for any mounting screws. Remove the screws to release the unit from the wall. You can remove the wires from the back by turning the connection screws counterclockwise. Make sure you do not let any loose wires fall between the walls.
Step 2: Clean the exposed wires by scraping then with a utility knife until the ends shine. Attach these wires to a new thermostat – the new unit must have the same electrical rating as the old one.
Step 3: Once the wires are secured to the new thermostat, push them back into the wall and tape up the opening to prevent cold air inside the walls from affecting the thermostat.
Step 4: Install the new mounting screws to fasten the thermostat to the wall. If the new thermostat has mercury tube, set the unit against level during installation. Mercury tube thermostats must be exactly level.
Step 5: Snap the face plate back into place. Make sure the new unit turns the heating and cooling system on and off when the temperature is adjusted.
Following these guidelines will ensure your new thermostat is up and running for a comfortable winter. As always, if you need assistance with your heating needs this season, call Heatmasters!
Courtesy of How Stuff Works
http://home.howstuffworks.com/home-improvement/heating-and-cooling/thermostat-maintenance-tips2.htm
