Where the heck did my hot water go

June 13, 2005 8:36 AM

I've painstakingly and scientifically ruled out all of the other possibilities. My hot water heater is inhabited by the Virgin Mary.

Mysteriously, when I turned on the hot water tap yesterday, only cold water came out. The hot water heater's pilot light was lit; it was making reassuring noises; we had not been using any hot water during the day; and the temperature in California was not cold enough to affect the pipes. There had been a mild earthquake in the morning. The hot water heater is 1 year old; the pipes, 25 years old. Broken pipes, right? So I resolve to call the plumber in the morning. The only thing is, I turn on the hot water this morning, and it works just fine! Does anyone have any rational scientific explanation for what the heck happened to approximately 30 gallons of hot water yesterday?

posted by felix to home & garden (16 comments total)

Make a website and start selling tickets - clearly the VM is living in your water heater.

Our lady of disappearing hot water - pray for us.
posted by jmgorman at 8:56 AM on June 13, 2005

can you see the burner, or just the pilot light? i don't see how broken pipes would change the temperature of the water (you might get water everywhere, but it wouldn't change temperature). maybe there was some dust or something on the burners/ignition that stopped it from lighting? gas water heaters are amazing things - i asked for help with mine here about 6 months ago, and only worked out what was wrong a couple of weeks ago. they're surprisingly complicated for something so apparently crude.
posted by andrew cooke at 8:57 AM on June 13, 2005

Is it possible that the gas had been turned off as a result of the earthquake and was only restored shortly before you checked out the heater? A tank of water could take several hours to heat up.
posted by RMALCOLM at 9:58 AM on June 13, 2005

I would second RMALCOM above; if you hadn't had the hot water heater on all day, it shouldn't have been making many noises. If, on the other hand, your gas had been off and it had cooled substantially, it could be heating back up...

Just a guess, however.
posted by sohcahtoa at 10:07 AM on June 13, 2005

But if the gas was off he would have had to re-light the pilot light, no?
posted by Four Flavors at 10:26 AM on June 13, 2005

How long did you let the water run? If you had not been using any hot water during the day, the water in the pipe leading from the tank to the tap (which could be quite long) would have cooled.
posted by weapons-grade pandemonium at 11:10 AM on June 13, 2005

During the period when the water was cold, I determined that it was cold by filling up a bath -- more than enough gallons for any cold water in the pipes to have flushed out. Although our piping is ancient, normally the hot water tap heats up within about ten seconds.

We took no steps on our end to turn off the gas etc as the result of the earthquake, although upstream gas turnoff is a possibility -- except that the water heater's pilot light was on, and what I believe is the burner was flickering happily away. I would have expected both to go out, if the gas had been turned off.

Apart from the Virgin Mary, my new theory is that there is a leak somewhere in the pipes -- that self-heals over time (metal expansion, debris, something). The earthquake maybe disturbed the leak, causing the 30 gallons of hot water to get out. The leak healed, restoring hot water to the rest of the pipes. No, it doesn't make sense. Chewbacca would not want to live on Endor. I have no idea. Anyone else wanna take a shot?
posted by felix at 11:48 AM on June 13, 2005

The end of the thermocouple that attaches to the gas control could be corroded/dirty. Or the valve itself could be sticking. You could also have had your dip tube break off/crack at the top of the tank. This can intermittently allow cold incoming water to go directly to the output connection. A hotwater short curcuit if you will.

Warning: Doing the wrong thing with gas bits can blow you; your house; even your whole block up. Do not proceed if you do not know what you are doing.

If it is the thermocouple you can unscrew the nut fastening the thermocouple tube to the control and then clean the end of the tube. A piece of denim fabric is fairly effective.
posted by Mitheral at 12:39 PM on June 13, 2005

FourF: perhaps he doesn't really have a pilot light; newer equipment has electronic ignition for safety.

Perhaps the gas lines had been turned off while the country assessed safety and then turned on later. When they turned back on his heater came on and what he saw was not a pilot light but the actual burner.
posted by phearlez at 1:29 PM on June 13, 2005

Can a hot water heater truly be said to possessed of the Virgin Mary, when it is apparently a little fucked?
posted by five fresh fish at 2:54 PM on June 13, 2005

it was an earthquake, right? that's an act of god (in our insurance policy at least). so i think your worries are unfounded - being fucked by an act of god is pretty much part of the job description for the virgin mary.
posted by andrew cooke at 3:27 PM on June 13, 2005

If the gas had actually been shut off somewhere central, wouldn't a utility-company technician have to come by each affected house to make sure the lines were repressurized correctly? That's what they do after residents shut off their own gas.
posted by expialidocious at 3:48 PM on June 13, 2005

I would suspect that a central shutoff would have been a major event, with everyone being commanded to shut off locally before they turned it back on globally to avoid a suburb-sized ball of flame.

Also, the earthquake was of a minor, jiggle-the-bed variety -- maybe an inch or two of displacement over a period of about 10 seconds, and that happens up to several times a month in Los Angeles.

I'm liking the idea of the thermocouple being off kilter, because that is a lot less expensive than 20+ year old steel piping being replaced, it has the benefit of being a sporadic event conceivably triggered by minor variations, it is a relatively recent system (only a year old) that might not have gotten fixed yet, and finally, I am not yet ready to accept Jesus into my heart.

Thanks to all for the thinkings.
posted by felix at 4:13 PM on June 13, 2005

Ooh, touche', Andrew! :-)
posted by five fresh fish at 5:53 PM on June 13, 2005

Kudos to Mitheral for coming up with a legitimate use of the HTML blink tag.
posted by danb at 6:49 PM on June 13, 2005

I was so happy it hasn't been banned.
posted by Mitheral at 7:10 PM on June 13, 2005