legacycentral bbs

Does anybody have a good grasp of how natural gas water heaters work?

Ours wasn't operating this morning. I found some water on the floor next to the heater. It wasn't much, but there is a drain so for all I know it could have been a lot. In fact, it may well have been a lot because it seemed like a lot of the area was damp.

The line coming off the relief valve at the top was dry. The drain line and valve were dry. The inlet and outlet fittings at the top were dry. That means there must be a leak in the tank itself, right?

But why would a leak in the tank make the heater shut off? I'd think it would still run, but just keep the burner on all the time.

One more thing -- I checked the relief valve by operating it by hand. After I'd dumped maybe a cupful of water out the top, the burner fired up. I don't understand why this is the case.

Right now it's heating the water, so I'm hopeful we'll be able to shower. But from a safety perspective, is there a reason I should shut off its gas and water supplies?

Thanks for any help.

Hmm, okay, in about the time it took me to make the above post, the burner shut off again.

From my understanding you need to be careful if the ignitor was submerged in water or got wet. They recommend replacing it if it does. Was there water in the basement? If it flooded and the ignitor was submerged then it should be serviced. But if you didn't have to manually reignite it then it must have been another reason that shut it off. Check the thermostat, if it didn't shut off at the right time then it's possible that the pressure built up due to overheated water causing increased pressure. Just a guess.

It may well have flooded to a certain degree. There's a drain there but it probably wouldn't have been able to handle a lot of water all at once.

I hadn't considered the ignitor being potentially wet... I did just find that the pilot light had gone out, so I shut the gas off and we're looking for the manual.

I'm very curious to know more about the control system -- is it the temperature of the flame or of the water that is regulated? And what are the safety mechanisms? Clearly if the flame goes out it should know better than to just keep supplying the fuel. I wish I had a schematic.

Thanks, Scott.

If it was leaking or had a leak it would not stop leaking. Typically when they go they let all the water out of the tank and the inlet just keeps supplying the flood. I got alot of help from dzx (and his uncle) when my boiler was acting up, I also got alot of info from www.heatinghelp.com this link is to their "the wall" section which is where you can post questions http://forums.invision.net/Main.cfm?CFApp=2l

Thanks, Mike. This seems odd because it's no longer leaking. I'll take a look over there and maybe dzx will grace us with his help and his uncle's when he has a chance.

Alright... figured it out. There's a small leak in the tank. It's so small that it doesn't really show up until it's heated. A minute after we re-lit the pilot light, it started dripping drop by drop onto the burner.

So I guess it's time to do the research on a new water heater...

The temperature is controlled via the temp of the water, not the flame.

The pilot light stays lit. When the water temp drops, the main burner kicks on.

If the pilot light goes out, gas will/should shut off. It does on mine, and it's mildly old.

Are you guys renting or own the place. If you're renting, have the landlord take care of it. It's their responsibility.

Thanks, Josh. I did get it figured out after we found the manual.

The burner controller has a piece sticking into the tank, which is how it senses water temperature.

There's a thermocouple mounted right next to the pilot burner, which is how it knows whether the pilot light is lit.

One of our housemates owns the place. I'm helping her figure out how to deal with this problem.