Water Heater Won't Stay Lit

My water heater burner won't stay lit. Here's what I know:
1. If I light the pilot, it can stay on indefinitely. So I think the thermocouple is actually functioning. 2. If I then turn on the burner, after a few seconds there will be a *click*, and the whole thing shuts down. This takes less than a minute.
I have removed the burner assembly, and uploaded several pictures to photobucket to illustrate the situation. http://s150.photobucket.com/albums/s99/someog/Water%20Heater%20Problem /
Questions: 1. One thread I found on the internet suggested that when the main burner comes on, the draft pulls the pilot light flame away from the thermocouple, causing it to cool. Is this plausible? If so, how do I fix it?
2. If that isn't it, what else might be wrong, and what is the solution?
3. What is that element that's wired into the thermocouple (visible in pictures 6 and 7)? I don't recognize it, and every thermocouple picture I find on the internet doesn't have it.
4. The thermocouple appears to be soldered into its bracket. Is this common practice?
BONUS QUESTION: Does anyone know what the heck that is in picture 10? It's a tool belonging to my friend, and neither of us know what it is. It's two parallel edges, perpendicularly attached to a single square tube. The edges are lockable via the white knobs, and one has a hinged piece on the inner side that swings out maybe 10 degrees from the tip. In the picture, it has swung out about as far as it's able to. What is it?
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Part of a Pana Vise for holding circuit boards
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Clean the flame sensor...
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first replace the thermocouple, its always best to elminate the quick easy cheap issues first
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http://s150.photobucket.com/albums/s99/someog/Water%20Heater%20Problem /
I cleaned it with 100-grit sandpaper. I uploaded the results to the photo album. Reinstalled the burner assembly...still doesn't work. Now it will only stay on as long as I actually hold the button down.
Is it expected for the thermocouple to be soldered in place? I think I have to replace it now, but have no soldering equipment.
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.
It's usually a push-in clip or threaded collar.
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...
Question on picture #13. How did you get it to light outside the water heater? Nice blue circular flame!
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om...
Well, I don't really _want_ to tell you because I'm anticipating a cringeworthy reaction, but...it's next to the water heater, with everything attached (just rotated), and set on "Pilot Light". I wanted to see where the thermocouple was in relation to the pilot light itself, and couldn't see it through the viewport.
As a followup, it didn't work when reassembled because during reinsertion I broke the fusible link (the S-thingy in pics 6 and 7). I thought about trying to solder it back together, but thought "eh, heck with it."
It was a State Select GS560YBRT water heater, and it's not possible to replace the thermocouple on those; I had to order a new pilot assembly. It'll arrive in the next few days, and set me back $60.
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On Mon, 18 Apr 2011 15:52:15 -0700 (PDT), " snipped-for-privacy@gmail.com"

That was a good move.
--Vic
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Final followup: the part arrived. It only took about 15 minutes to install, and I have hot water again.
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snipped-for-privacy@gmail.com wrote the following:

If you don't have the tools and don't know how to fix the problem, you should call in a professional.
--

Bill
In Hamptonburgh, NY
  Click to see the full signature.
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willshak wrote: snip

I normally dislike this advice, but in cases where you risk burning down the house, it sounds rational. Making it "work" is not necessarily the same as making it "safe".
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On the one hand, it's hard to argue against that logic. On the other, I had already called in the "pros" twice. Two different companies came out and gave two different diagnoses, replaced parts, and charged me a total of more than $300. When it went out the third time, I started googling and did it myself. Not saying you guys are wrong in general, just saying that two different companies combined to bat .000 in my case.
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Point taken...and well done on your "part".
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On Mon, 18 Apr 2011 11:25:45 -0700 (PDT), " snipped-for-privacy@gmail.com"

I've never had a gas water heater, but is 100-grit sandpaper really the way to clean it? I have an oil furnace and I just use a paper towel to clean the flame sensor.

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snipped-for-privacy@gmail.com wrote:

Had a gas oven like that. It was buildup on the thermocouple or flame sensor. Cleaned it off and all was fine again.
--
If your doctor isn't taking new patients,
he ain't curing any of them.
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If that were what was happening, it would fire up and go through one heating cycle, then fail to light the second time.

Water heaters have some sort of failsafe over temp that comes into effect if the water gets too hot. It only acts once, can't be reset and then you need a new gas valve unit. But exactly how the symptoms manifest after it goes off, don't know.

Never saw that either. It's not clear how it's wired in, but it might be some kind of over-temp fuse that acts if the pilot light gets to big, or flame is around it where it shouldn't be. Is this a relatively new unit? They did add some gizmo a few years back to prevent water heaters from blowing up basements where you fill the whole place with solvent fumes and fail to turn the burner off.

Can't tell from the pics, but it looks like it might be spot welded on. I would not expect it to be soldered.

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You haven't named a brand or model, that just might help!!!! Have you contacted the manufacturer's hot lin?. On something as potentially dangerous as a water heater, they must have some sort of a hot line.
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Gas water heaters built in the past 5 years or so in the US are required to have sealed burners. Since you can't have a flame without oxygen, they have what's called a flame arrestor, which is a honeycomb like filter that allows air to pass through, but won't allow a flame to go the other direction. Flame arrestors are notoriously susceptable to plugging up with dust, so the burner also has to be protected with an oxygen sensor.
It sounds like either your oxygen sensor is bad, or more likely, that there isn't enough air getting to the burner to support a full on flame.
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