Replacing/changing a thermocouple at home is a very easy process. With the tips given below, know how to fix thermocouples yourself.

How To Replace Thermocouple

Thermocouple is an instrument used for the purpose temperature sensing. Apart from that, it might be utilized for the purpose of converting thermal potential difference into electric potential difference. Thermocouples are used in a number of heating equipments, the primary being furnaces and gas water heaters. With time, the thermocouples get worn out and need to be replaced by new ones. Most people call electrician to do the same, however, you can easily do the same at home. To help you in this, we have provided the complete procedure of replacing or changing thermocouples, along with some tips.
How to Replace a Thermocouple
Furnace Thermocouple
Items Needed
  • Replacement Thermocouple
  • Screwdriver
  • Wrench 
  • First of all, shut off the gas valve for the furnace and remove the screws from its front panel. This will provide you access to the upper and lower panel, from where you will get hold of the thermostats.
  • Now, unscrew the top front panel and locate the thermostat (next to the pilot light).
  • Remove the copper lead and unscrew the gas line connection nut as well the bracket nut holding the thermocouple tube in place.
  • Take out the old thermocouple and slide the new thermocouple into bracket hole. Make sure that the steel tube faces up and the copper tube faces down.
  • Tighten the bracket nut, underneath bracket, to secure the tube in place. Now, connect the copper lead to the gas line.
  • Making sure that the connection is clean and dry; tighten all the nuts with your hand.
  • For replacing the lower thermostat, you will need to remove lower access panel and repeat the steps.
  • Finally, turn on the gas supply and relight the pilot light. In order to be sure that the new thermocouple is working properly, leave the pilot light lit. 
Gas Water Heater Thermocouple
Items Nedded
  • Replacement Thermocouple
  • Screwdriver
  • Wrench 
  • Just like in the above case, shut off the gas valve on the water heater as well as the one on the line near the heater.
  • Remove the burner assembly, by taking out the outer and inner doors. At the same time, loosen the pilot and supply tubes, along with the thermocouple connections.
  • Next, loosen the screw that holds the thermocouple to the bracket and take out the thermocouple.
  • For installing the new thermocouple, position it in such a way that the pilot flame heats ½ inch of the tip.
  • Put the burner assembly back, in the water heater. Tighten burner supply tube, pilot tube and thermocouple connections. Make sure that you do not tighten the thermocouple more than a quarter turn more than hand-tight.
  • Turn on both gas valves and heat the thermocouple tip by igniting the pilot light. Replace the inner and outer doors.

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