What is a Thermocouple?

Furnaces are made up from a bunch of different parts that make it heat your home like it is supposed to. One of these parts is your thermocouple. The thermocouple acts as a safety feature that shuts the gas off to the furnace when needed. Two different types of metal coupled together make up the thermocouple. A thermoelectric effect called seebeck effect causes the thermocouple to sense temperature change. When the temperature rises it creates an electrical voltage in the two metals that also rises as the temperature increases. One end of the thermocouple is in the pilot light and the other end is in the shutoff valve of the main gas line. When the pilot is lit, the thermocouple keeps the gas valve open. When the pilot light goes off the voltage on the thermocouple drops allowing the valve to close so that natural gas isn’t streaming out of the furnace when it is not needed. This is for safety because normally the pilot would ignite the natural gas and when the pilot is off the natural gas would just be flooding the combustion chamber. This is dangerous because the tiniest spark could ignite the chamber full of gas causing major issues for the home owner. Even besides the possibility of sparking and igniting the furnace is the possibility of carbon monoxide leaking out into your home. Carbon monoxide is a gas that you can’t see, taste, or smell that can poison you and your family leaving you to find out when its typically too late. The signs of carbon monoxide poisoning are the same as the flu, you get dizzy, nauseated, headaches, and trouble breathing. If this happens you should seek medical attention right away. The thermocouple prevents this from happening because once it senses the pilot going out it shuts the gas valve off. Your thermocouple is important and needs to be maintained. They are not made to last as long as your furnace so it is likely that you will have to replace it a time or two. Make sure you get your furnace inspected at the beginning of the cold season each year to make sure all parts including the thermocouple are functioning correctly so you have peace of mind. The check up will give the technician an opportunity to make sure the thermocouple is in working order and gives you time to replace it if necessary. The professionals at Bartlett Heating and Air are well trained in inspecting and repairing your furnace so call us today for any of your heating needs!