Have you ever jumped into the shower to discover there is no hot water? Or turned on your furnace thermostat and nothing happens? Chances are you have a bad thermocouple.
So just what is a thermocouple, how does it work, and why is it important to the safe operation of your hot water heater and furnace.
Basically, a thermocouple is an important sensor on your gas appliances that senses if your pilot light is operational, and whether or not to allow the gas valve to turn on, supplying a flow of gas to the burners. If the pilot light is not on, and the gas valve were to open, sending gas to a burner that cannot be light, it was immediately create a very dangerous situation, sending gas fumes into your home.
If it senses no heat from a pilot light, it will immediately turn off the main gas valve, turning off any flow of gas into the pilot light or main burner area. If it does sense heat from the pilot area, it sends an electrical impulse that allows the main valve to open when it receives a signal from the home thermostat.
Replacing a thermocouple is a very simple procedure. You can pick up this device from any home improvement store.