How to Test a Gas Furnace Thermocouple

The gas furnace thermocouple is an essential part of the gas boiler. It is 2 metal pieces that are joined at a junction, which is used to monitor the temperature of the pilot flame. This monitoring is necessary because the heat of the pilot flame sends the necessary voltage to open the valve to turn the furnace on. In order to test a gas furnace thermocouple you need to have an electrical voltage meter tester, a screwdriver, wrench, lighter, and a pair of pliers.

Process for Testing a Gas Furnace Thermocouple

Testing the gas furnace thermocouple entails turning off the furnace and allowing it to cool down in order to access the panel where the thermocouple is located (above the pilot flame). The voltage meter should be connected to the wires and using the pliers to hold the thermocouple, turn on the lighter in order to produce a simulated heat. The needle on the electrical voltage meter tester should move indicating that the thermocouple is operational.

If the thermocouple passes the test, place the thermocouple back in its place and close up the panel. If it does not pass the test, replace the wires for the gas furnace thermocouple.