How Does a Thermocouple Work in a Water Heater? | Repair and Replace

What does a thermocouple do in a water heater? What keeps the pilot lit? In this quick episode of Repair and Replace, Vance explains how the thermocouple works in a hot water tank. Additionally you'll see how the burner assembly ignites in a water heater with a conventional gas valve and what happens if the thermocouple isn't working properly.

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[RehmatAliWriter]

How does Universal Thermocouple works? Because it's not having two wires ending. Only one covered tube end. Normal thermocouple having two wires end for measuring generated millivolts.

[RB-nmko]

In the diagram, the thermocouple and burner appear to share the same gas line. But wouldn't the burner have its own valve, and if so, what opens and closes it? Thanks

[GodBearOutoors]

Will a faulty thermocouple cause a weak flame, or would it just stop any flow all together?
I have a weak flame going into the burner tube and have checked for the usual culprit, stinkbugs, but nothing.
Any help would be greatly appreciated.
Thanks

[playbackmedia]

Is it normal for the flame from top round flame disc to touch the thermocouple and ignitor?

[izzybronc]

Mine stops turning on until I turn up the knob. Then it turns on again but I keep having to raise the temperature after some time or it stops kicking on at current setting. Pilot has never gone out. Any advice?

[oscrfsh]

I have the opposite problem with my tank top heater....flame goes out but u can still hear gas pouring out.