Programmable thermostats are becoming more popular as people are focused on saving money. These thermostats allow the homeowner to set heating and cooling programs that use the most energy only when people are present in the house. They are reliable for the most part, but they do malfunction occasionally. Knowing what's wrong with your programmable thermostat will help you decide if it needs replacement.
Check the batteries. If your thermostat is not controlling the heat and air conditioning based on the settings you have programmed, the batteries may be getting low. While most programmable thermostats will give you a "low battery" signal, some may not. If the batteries are more than 6 months old, replace them. Take the front cover off the unit and find the battery compartment. Most programmable thermostats run on AA batteries. Turn the unit to the "Off" position before changing the batteries. Replace the batteries with high-performance ones. Replace the front cover and switch the thermostat back on. If it is still not working, go on to the next step.
Check the fuse. Most programmable thermostats contain a fuse to control power levels. The fuse has a filament inside like a conventional light bulb that will separate when an overload of power goes through it. If the filament is separated, pull out the fuse and take it with you to the home improvement or hardware store to find a replacement.
Test out the opposite system. If the thermostat is not properly controlling your furnace, switch it over to air conditioning. Change the temperature up and down to see if the thermostat is following its programming. Do the opposite if you are having a problem with your air conditioning. Turn on the heat. If the problem exists in one system and not the other, it is likely that the problem is not in the thermostat, but in the system itself. Call in a service technician to assess the repair necessary for your heating and cooling system.
Replace the thermostat if the problem is occurring in both the heating and air conditioning cycles and the above steps have not addressed the problem. The thermostat contains a small circuit board that can wear out or otherwise break. Check with the manufacturer to see if the thermostat is under recall or still under warranty. If it has been recalled by the manufacturer due to defects, you will be able to send it back to them and they will send you a new one for no charge. That will also be the case if the thermostat is still under warranty. If you do have to purchase a new one out-of-pocket, you should be able to find a new programmable thermostat from $30 to $50.
Install the new thermostat, according to the accompanying directions. Putting in a new thermostat is a simply process that almost any homeowner can accomplish. Replacing the thermostat should correct the problem. If it does not, call a technician to have a look at the entire heating and cooling system in your home.
Narrow down whether the problem is in the thermostat or in the heating or cooling system itself.