The L5 Upper Left Thermocouple mounts to the front of the heat exchanger and functions as a heat sensor. This sensor ensures that the water heater is running properly and is mounted vertically. If you feel you may need to replace your current Eccotemp thermocouple, please call Technical Support at 866-356-1992 if you feel you need advice. Very easy installation comes ready to plug into existing wiring harness.
Customer assumes all liability when purchasing replacement parts.