Replace Thermocouple
 

Anyone ever replaced the thermocouple in a water heater? How difficult is it? I've read some instructions on how to do it but I'd like to hear from others.

It's fairly simple. No special tools required. It'll probably take half an hour the first time, depending on insulation & obstructions.

There are different sizes so it's a good idea to take the old one with you when you buy the replacement.

The only nugget of wisdom I'll offer is to be gentle when forming the tubing. Kinks are not good. Thermocouples are available in 6" increments starting at 12", but a bit longer isn't a problem. If I'm out of a given size, the next bigger one gets installed-that's better than no heat. :D

You will need a adjustable wrench. Loosen the burner assembly, pilot tube and thermocouple from the gas valve and remove it from underneath the tank. Remove the thermocouple from the burner assembly. If you have a source of compressed air this is a good time to blow out the burner and pilot burner. Reinstall the new thermocouple and put everything back in reverse order.