This Is our Village

Thursday, June 24, 2010

A WATER SHUTOFF QUESTION

Assuming an owner has left his apartment for a period of several months and has not had his water to the apartment turned off, and assuming the person has not shut off the breaker for the water heater in his electrical panel…....

If we as an association shut off the water to that apartment (at the meter or at another outside shutoff to the whole apartment), do we run a real risk of the water heater burning out? Is it likely, in other words, that over a period of several months enough water in the water heater would be lost through evaporation so one or more of the heating elements would burn out?

If so, it would seem incumbent upon us that we not only shut off the water, but also shut off the breaker. And since the breakers in many of our panels are incorrectly labeled (if labeled at all), it would seem we would have to carefully check the 220-240 volt breakers (try to run the stove, try to run the a/c) to be sure we were shutting off the right one.

Any advice on this?

2 comments:

  1. I guess we need yet another preventive campaign - labelling fuse boxes. To the best of my knowledge the water heater can burn out, as you describe.

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  2. Since there has been only one comment to date on my post (thank you, Elaine), I thought I’d comment myself, sharing what two friends told me. They are both experienced with hot water heaters and agreed that yes, if left with no water supply and the electricity on, over time the heating element(s) could burn out. Therefore, one should shut off the breaker to the water heater when shutting off the outside water supply.

    The water in the tank would not evaporate out quickly (say, over two weeks), because the water heater is essentially a closed system. Also, the uppermost heating element (coil, usually U-shaped) is generally located about a third of the way from the top of the tank, so in a typical 30-gallon tank almost 10 gallons of water would have to evaporate before the coil was not surrounded by water.

    When a coil burns out, it normally just disintegrates with little danger of fire. A coil in a water heater CAN be replaced. (Whether this would be feasible, especially in an older appliance, is another question.) It is possible there could be fire damage, though, if through evaporation of water within the closed system, hydrogen gas were produced as sometimes happens, the hot coil ignite this, and there be a small explosion.

    From what these two guys and you have said, Elaine, it would be best to play safe and shut off the water heater circuit breaker WHENEVER shutting off the water supply.

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