Rewire two 80 gallon off-peak electric hot water heaters?

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mnRemodeler

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I have two 80 gallon hot water heaters for off-peak electric. Except there are a couple of caveats. First, the power company came and removed the off-peak meter. They said we would continue to be charged off-peak rates but it wouldn't really be off-peak any more. (good for us)

Second, the electrician wired them up wrong. For off-peak, the top element on 1 heater and the bottom element on the other heater should be energized with the theory that they will thermal siphon. Well, they are wired backwards in relation to which heater has the cold water entering it.

Third, in the winter time I turn off the electric and use the tanks only for storage. I have an outdoor wood boiler that makes hot water (through a water-to-water hx as fast as we use it. We have unlimited hot water.

Now the problem. We have a B&B with a 50 gallon whirlpool tub and we run out of hot water before the tub is filled. This is summer months only when using the electric heaters and not the wood boiler.

So I'm considering wiring each 80 gallon heater to be on its own electric circuit and with each having both elements in use. This should effectively give me 160 gallons of hot water.

What I don't know is if the fact that the heaters are wired backwards is the problem or if its just that filling a 50 gallon whirlpool is going to take more hot water than an "off-peak" electric hot water system can handle? Should I fix the wiring and try it again?

I'm leaning towards putting each tank on its own electrical circuit with all 4 elements getting power and then installing blankets on the heater to make them more efficient.

Thoughts?
 

hj

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The heaters would have had to be rewired, or ordered for "peak wiring" for him to have been able to wire them the way you describe, and I am not sure what you mean by "wired backwards". For all elements to work simultaneously, you need FOUR circuit breakers and circuits, not just two.
 

MACPLUMB

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You would not be able to run all four elements at same time without a lot more electricity then most homes have,
they way they work is the two upper elements come on then when the upper thermostat is satisfied the lower elements come on to finish heating the tanks
 

WorthFlorida

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Now that you're paying only a single rate all day, are two tanks really needed during the time you're not using the wood fired boiler? Perhaps a better way to get the quantity of hot water for the whirlpool add a thermostatic mixing valve on the HOT output of the tank and the cold water to its input side. Add a thermometer on the output of the mixing valve. Then raise the tank temperature (both top and bottom thermostats) to about 140-150 degrees. When it reaches temperature run the hot water and adjust the mixing valve so the output temperature is not more than 120 degrees. There are round dial thermometers.

When your using the wood fired boiler to heat your water, the temperature of the water may already be too hot so a TMV would be needed for safety.

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Master Plumber Mark

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all this trouble just to get your whilrpool tub filled with hot water???
so how often does your wife need to use the whirlpool???


I assume you are using the potable water in the 2 80 gallon electric heaters to heat the home
during the winter months through your wood burning stove too correct?
Sooo Are the heaters plumbed in series or
parallel???

if you have them plumbed in series there should never be a problem with not having enough
hot water in the summer time to fill a 50 gallon wp tub... You simply set the the number one unit where the water enters the sysetm on low and you set the number 2 unit that it exits from on med to hot

If this is plumbed in
parallel there might be the
good possibility that the system is drawing off just one of the heaters and not the other one in the summer time
and it could be drawing more from the unit that you have turned down on low ........

you ought to post a picture of this mess for everyone to look at
before you get into deep re-wireing the whole thing

Am I making any sense to you about this???





 
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