Download How to test water heater thermocouple

How to test water heater thermocouple
When two wires made of different metals are joined and one of the ends is heated, there
is a continuous current which flows in the thermoelectric circuit.
Instructions: Disconnect thermocouple from the gas valve thermostat using 7/16” wrench.
Using multimeter with alligator clip leads:
Attach red lead to the body (copper part) of the thermocouple.
Attach black lead to the end (silver part) of the thermocouple that connects to thermostat.
Follow instruction to light the pilot and watch voltage readings on the multimeter.
If thermocouple is good, then after 45 seconds the meter should read 12 millivolts or more.
How to replace thermocouple
Note: If the pilot lights even for a moment, then ECO is not tripped.
Typical multimeter might
not have alligator clips.
Without alligator clips
you may need extra hand
to keep pilot flame lit
during test.
Re-connect thermocouple: finger tight + ¼ turn. No teflon tape on threads.
Typical Gas valve thermostat
For more troubleshooting resources:
http://waterheatertimer.org/How-to-install-gas-water-heater.html#troubleshoot