Apparently there was a class action suit related to this model due to it's unusual and scarce thermocouple. The manufacturer now offers a retrofit kit to resolve the problem. Registered owners should have been contacted. A simple call to the company describing the problem and they will send you the rebuild kit overnight at no charge (perhaps not if it is out of warranty?).

The above information was primarily distilled from the 411plumb.com site. In particular the troubleshooting-flame-guard-flame-lock-water-heaters article.

I ordered the rebuild kit without problem but didn't want to be without hot water for 2 days while waiting for it so I took a shot at a temporary repair.

I purchased a generic replacement thermocouple (Honeywell from home depot) and cut off the connector end. Then I cut off the defective sensor and fusable link (fat part of the wire) from the old thermocouple. Then comes the tedious part ...

DISCLAIMER: THE FOLLOWING INSTRUCTIONS ARE AN OVERVIEW OF WHAT I DID, NOT A COMPLETE RECIPE AND ARE ONLY FOR THOSE THAT ARE COMPETENT WORKING WITH GAS AND ELECTRICITY. I'M NOT RESPONSIBLE IF YOU SHOCK YOURSELF OR BLOW UP YOUR HOUSE.

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The thermocouple wire is really a wire within a wire, similar to a coax TV cable. The inner wire is coated with thin insulation. So you need to cut off a section (at least an inch) of the outer wire without nicking the inner wire's insulation. I used a cutting wheel to cut a notch all the around the outside and most of the way through. Once notched a gentle bend will break it allowing you to pull it off. Then scrape off the insulation from the inner wire, all but the last 1/8 or so by the outer wire. Then clean the bare inner wire and the outer wire near the cut with abrasive pad or fine wire brush to get a good contacting surface.

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Then place the wires next to each other and strap or clamp the outer wires together so they have good electrical contact. I used 2 cable ties to bind the wires together. I avoided soldering because others said there may be issues with different metals and I didn't feel like experimenting. Then I used a wire nut to bind the inner wires together. Now everything works like a champ.

I did all the splicing on the outside to avoid any issues with the combustion chamber. There should be no danger to people on the outside due to the ridiculously low voltage and current involved. And this only has to last a couple days until the rebuild kit comes. Just block off the area to keep people and pets from messing up the connection. Don't let the inner wires touch anything else or the signal will likely be messed up.

"I love it when a plan comes together." And my family loves not taking sponge baths for 2 days!