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creamaster 08-17-2009 03:41 PM

Do I need to turn off water heater?
I just did some plumbing work for 2 hose bibs and it was my first time soldering copper pipe together so I am a little nervouse because I did the work last week and we are leaving for vacation for a week. I want to turn off the main water valve because noone will be around to check on the house. My question is do I need to turn off the natural gas water heater if I turn off my main water valve? Instincts tell me no but never hurts to ask.

Thanks :thumbsup:

darsunt 08-17-2009 05:49 PM

Just set the water heater control knob to pilot. I believe the pilot light will continue to burn, but the main burner will not light.

Paragon 08-17-2009 05:58 PM

creamaster, if I am interpretting your question correctly you are wondering how to prevent flooding your home via the water heater while you are gone correct?

If I have interpreted the question correctly once you shut off the valve bringing water into the house no other water will flow into the water heater. Now if your water heater is severely corroded it is not out of the question that you could come home and have 40 gallons or whatever size your water heater is of water on the floor but if the main valve is shut off to the house (and it works correctly) then you have nothing to fear or at least you won't have to fear a continual flow of water occuring and floating the house.

Is this basically what you were wondering? If I answered your question then shut er down and enjoy your time away!

Good luck, be safe

MACPLUMB 08-17-2009 08:18 PM

Water heater shutdown





darsunt 08-18-2009 12:05 PM

Hmm, I did not know about that. In fact I don't know anyone who is aware of this. Just read an interesting internet article about it, though.

How likely is the legion bacteria to be in the tank? And wouldn't bringing the tank to full heating temp kill anything off in there?

I agree that nothing bad is likely to happen when leaving the tank on.

adpanko 08-18-2009 01:22 PM

Shutting off the main supply to your house will turn off the flow of water to everything in the house, including the pressure coming into, and out of, your hot water tank. But all of the piping in your house will still have water sitting in it (albeit unpressurized), so if you were to somehow get a crack in a pipe or a washing machine supply or something, you wouldn't have a geyser coming out of the crack, only a leak pressured out by the gravity of the water remaining in your plumbing.

But if your hot water heater were to rust out while you were away, you'd have 40 or more gallons of water make its way out onto your floor. There is no way to prevent against that, other than to drain your tank before you leave, but that seems a little over the top precautionary.

AllanJ 08-19-2009 07:41 AM


Otherwise if the tank should spring a leak and empty out while you are gone, then the burner or elements will come on full blast possibly setting the house on fire.

And turn on a hot water faucet and make sure water is gushing out before turning the water heater back on.

Turning the water off before going on vacation is generally a good idea although there are exceptions and idiosyncrasies that are too lengthy to describe here.

darsunt 08-19-2009 10:25 AM

That's the thing I would worry about, even though it is extremely unlikely.

But how serious to take this legionaire's disease stuff?

Paragon 08-19-2009 11:07 AM

Here is an excerpt from IWILLTRY.ORG:

What’s the best water temperature to aim for?

"There is a hot debate (pun intended) about what is an appropriate temperature for domestic hot water heaters. Some recommend water temperatures under 50C to prevent scalding (especially important if you have children). Others recommend a temperature of 60C or higher to kill bacteria. The primary bacterial concern is Legionella bacteria which can cause Legionnaire’s Disease. The Centers for Disease Control and Prevention estimates 8,000 to 18,000 Americans contract the disease annually (about 1 out of every 20,000 people) with 5 to 30% of cases being fatal. High risk groups are the elderly, smokers, the immuno-compromised and those with chronic respiratory illnesses. According to this article, it’s not necessary that water temperature be maintained at 60C to kill the bacteria. It’s only necessary that the water temperature be raised to 60C at least once per day. A great way to accomplish this with minimal energy consumption is – you guessed it – by running a tank on a timer just as I’ve described above. Commercial electric tanks have heating elements located near their midsections leaving some water at the bottom of the tank that will be cooler than 60C even when the tank is set to 60C. Thus Legionella bacteria are almost always found in electric tanks rather than gas or oil ones. The converted hot water tank I’ve described, however, should not suffer from this deficiency since the heating element can be lowered to the very bottom of the tank. I personally aim for a temperature of only 45C at the point of use for morning showers. It’s up to you whether you want to run your tank up to 60C or reduce your energy consumption and scalding risk by targeting a lower temperature." page 3 cites that tanks are to be considered a potential source of legionella.

These are just 2 but it looks like their is some viability to the argument so I don't think I would turn off the heat source becuase if you should spring a leak the worst that is going to happen is your elements will burn out. The tank isn't going to be any good anyways because it has a hole in it.

So I think it is sufficient to simply turn off the water source to the water heater and go enjoy yourself away from home. This is not something to panic over because after all 40 gallons of water isn't that much and if your soldering job lasted this long you should bein the clear (with 99% certainty, lol but then you can't be 100% certain about anything after all the solder might be defective or you maight have a pipe burst somewhere else. So I would just turn off the water source and not worry about anything by doing that you are doing more than the vast amjority of people in this country, I know I never do, lol!

Good luck, be safe.

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