Leave electric hot water tank full or empty?


Hi,
We're looking after a house which has been vacant for about 6 months, and will be vacant for at least a few more. We check it every 2nd or 3rd day.
Nova Scotia, Canada, climate in winter is cold, often well below freezing, sometimes down to -20C or lower (about -6F). 5 year old hot air oil furnace set at about 68F, serviced this summer.
Two months ago, we turned off the main water supply valve, left all taps open and water drained, including outside taps, toilet tank empty. I forgot, so power flowed to the electric hot water tank until last week, and the tank was full.
Question: about draining the hot water tank, which now has the power supply breaker off:
Drain water, or leave full?
If drained, will the tank be more likely to rust from inside? If full, and the furnace fails, I suppose the tank may freeze and crack. If partly filled, what happens? Currently it's almost completely drained.
Tank is in heated basement, inlet & outlet pipes go upward. The basement laundry tub valves are open.
Thanks! Dugie
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Modern tanks are glass lined, so corrosion is not an issue. Just make SURE that the tank is filled (bleed air through hot water tap) before you turn the power back on, or you will destroy the heating elements. They will not work if there isn't water in the tank.
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Dugie wrote:

I would suggest draining it. If you do, turn it off and kill the circuit breakers to it first.
--
Joseph Meehan

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Stuff exposed to moisture AND air rust faster.
I would leave the tank full, but power up the water system right before home sale you you can check for leaks
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Why do you leave the home so warm, its just a waste of money. If you worry about freezing drain it, for 30$ you can get a unit that will call you when the temp drops below 40f, if the phones still work. If you are realy worried about freezing pour antifreeze in the traps and toilet, 68 for a vacant house is nuts.
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Thanks for the replies. There are differing opinions regarding draining or not, so still unsure what to do. Since it's almost totally drained, I may leave it as is.
Antifreeze in the traps - good idea! I used to do that in a school bus camper we once had.
The temp is at 68 to prevent mold, mildew, etc., but the necessary temp is just my guess.

Our own tank was a Sears glass lined swirl, but still rusted. It had been on blocks, so it may have rusted from the inside.
Dugie
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orefull-3133.bay.webtv.net...

Tanks ALL rust from the inside, the glass lining has flaws and rust occurs at those flaws, leaks also occur at fittings.
Tanks could be made of heavy gauge stainless but few would be willing to pay the price.
As is tanks last maybe 10 years if you buy a premium one. Assuming you statr at 20 years old you might buy 6 or 7 in a lifetime tops, thats a bargain, ' The OP could save a lot of money by leaving heat set at 50 degrees, and adding a freeze alarm.
The higher the temp the greater the heat loss.
its less energy to keep it at 50 than 70
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If nobody lives there winterise it and shut off the heat, you worry to much about mold and mildew. Plus you will kill any termites.
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snipped-for-privacy@webtv.net (m Ransley) wrote in 3131.bay.webtv.net:

I doubt there are termites there that far north. Not absolutely positive. I think fleas though croak below 50 degrees. Any time I was in a house where I even suspected there might be fleas, I would undress outside, put clothes in a plastic bag and toss them in the freezer overnight.
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Dugie wrote:

and water drained, including outside taps, toilet tank empty. I forgot, so power flowed to the electric hot water tank until last week, and the tank was full.

I drain my electric water heater completely when the house is not used. It could affect the life expectancy, though. My water heater is 51 years old.
Rob
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As mentioned, for leaving it vacant that long is a $ waste. Are there not places there that "winterize" houses so utils can be shut off?
Most of the repo I've looked at have everything off with labels on everything that it's been winterized, not to turn water main on and not to turn hot water heater on until it main is turned on and it refills. They use non-toxic antifreeze like that used in RV's.
I believe it was $75-100US which easily pays for itself in a month. But this was in the US midsouth. As far north as you are, not sure how the plumbing pipe in the walls would handle it. A service that winterizes would know the ins & outs.
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in

If it's unoccupied for a long time, I'd set the heat down to 50 or else winterize it and turn off the heat. Winterizing eliminates the problem of a heating system failing, power loss, etc. Never heard of a vacant house set to 68. I have mine setback to 60 at night, and I live here! If I'm going away for 10 days, I set it down to 45-50.
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Where I live in Ontario it's been really cold lately but our house out at the lake is 99% shut down when we leave for the year. Drain the tank and shut off at the panel. If you like tape the breaker with a note that says "Fill Tank with water". The cold in the house will be good for it and kill anything that is trying to call it come. My vote is to shut it down and stop worrying. The only thing we leave on is the electrical to the outside spotlights and security system.
Hi,
We're looking after a house which has been vacant for about 6 months, and will be vacant for at least a few more. We check it every 2nd or 3rd day.
Nova Scotia, Canada, climate in winter is cold, often well below freezing, sometimes down to -20C or lower (about -6F). 5 year old hot air oil furnace set at about 68F, serviced this summer.
Two months ago, we turned off the main water supply valve, left all taps open and water drained, including outside taps, toilet tank empty. I forgot, so power flowed to the electric hot water tank until last week, and the tank was full.
Question: about draining the hot water tank, which now has the power supply breaker off:
Drain water, or leave full?
If drained, will the tank be more likely to rust from inside? If full, and the furnace fails, I suppose the tank may freeze and crack. If partly filled, what happens? Currently it's almost completely drained.
Tank is in heated basement, inlet & outlet pipes go upward. The basement laundry tub valves are open.
Thanks! Dugie
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anyone who turns heat competely off is stupid or in for big surprise:(
the large temp swings make the plaster drywall seams crack, expansion and contraction, big chunks of plaster WILL fall from walls.....
plus low areas of pipes can still freeze, cracking pipes that may only show up later after water is on for awhile:(
any appliances with water washer, dishwasher need winterized too
easiest and safiest, leave heat low but keep home from freezing, houses are worth big bucks why risk it?
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Above two items would be my concern. I'm not sure what these winterizing services do/recommend/advise/guarantee. Maybe they don't even winterize that far north.

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