Water Heater Timer ?

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I plan on putting a timer on the hot water heater, but I am not sure the one I found will work. This is the one:
http://www.lowes.com/lowes/lkn?action=productDetail&productId0194-251-T104D89&lpage=none
My question is this. I have two hot legs Red and Black going to the water heater. (the house is 55 years old water heater about a year old). On the timer it has; "Line Load Line". My question is If there are only two wires (both hot) what goes where? I am sure there are directions that come with it, but would like to know before I order one.
Thanks Chris
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wrote:

The two wires coming from the water heater are Load terminals. The two wires coming from your main electric panel are Line terminals. You should have at least 4 terminals. 2 to the load, 2 to the line. Bubba
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Bubba wrote:

But you must have a ground connnection to the timer also.
The timer wiring diagram is at:
http://tinyurl.com/cqepdr
(Doubtful if you'll find a neutral in the heater wiring, but if so there's terminals for that as well.)
Since you got a 24 hour timer I'm assuming you're trying to save electricity by powering the heater down during certain times of the day or night. With the excellent insulation on modern electric heaters you may find that game isn't really worth the candle and it'll take you quite a long time before you recover the cost of that timer in reduced electricity bills.
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat \'57 EE)
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jeff_wisnia wrote:

We have one of the highest electric rates in the country where I live. Depending on which calculator I use it should take 3 to six months.
Chris
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Bubba wrote:

Yea, I finally found a pic without the protective cardboard and it showed all the terminals.
Thank you for the info though.
Chris
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http://www.lowes.com/lowes/lkn?action=productDetail&productId0194-251-T104D89&lpage=none
That timer will work fine for water heaters, however they make one (WH40) which is specifically designed for water heaters, as it has an external bypass switch to turn it on at off peak times, when you've run out of hot water. As far as the wiring goes, the 240 volt power is connected to terminals 1&3, and the two wires that go from the timer to the water heater connect to terminals 2&4. It doesn't matter what colors they are or if they are transposed.
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RBM wrote:

Thank You Chris
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Yes judging by the very slow** rate of heat loss from our current foam insulated electric hot water heater the use of a timer may not produce much in way of savings. Here most homes heat electrically anyway, so any heat 'lost' from the hot water tank helps heat the house anyway. ** Many years ago, with a then less well insulated hot water heater we went away for a couple of weeks, turning off the electricity to the heater as we left. Returning the water in the tank was still tepid; attesting to slow heat loss. Savings IMO will be mainly by reduction in use of hot water.
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OP is probably better off adding a additional insulation blanket around the existing tank and water lines.
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Yes judging by the very slow** rate of heat loss from our current foam insulated electric hot water heater the use of a timer may not produce much in way of savings. Here most homes heat electrically anyway, so any heat 'lost' from the hot water tank helps heat the house anyway. ** Many years ago, with a then less well insulated hot water heater we went away for a couple of weeks, turning off the electricity to the heater as we left. Returning the water in the tank was still tepid; attesting to slow heat loss. Savings IMO will be mainly by reduction in use of hot water.
The savings incurred from using a time clock on an electric hot water heater are from lower electricity costs. Typically, you use an oversized tank, like 80 or 120 gallons, and only allow it to heat during the night, (off peak hours), when your electricity utility charges a lower rate. It's understood that the tank will hold the heat, and as long as your household daily usage is less than one tank, you'll save money
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That assumes you have the appropriate meter, which most people don't.
I would expect anyone pursuing a timer option, would have checked with their utility company to see what types of programs and equipment they have.
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I don't see much advantage of putting a timer on, especially in the winter.
I'd like to put a timer on ALL auto defrost refrigerators, so it does not defrost during the day when its being used. !
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modern water heaters have excellent insulation.
good green idea that sadly wouldnt be effective, plus in the winter the heaters minor losses help warm your home.
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Before installing the timer, do this simple experiment. Measure the normal water temp, turn off the water heater for the time period you are going to have it set to go off, then measure the temp again.
The rate of heat loss is proportional to the temp difference between the tank water and the ambient air. As an example, if the tank is say 140F and cools down to 130F over that period, the delta only goes from 140-60=80 to 130-60=70 at the end of that period. Or you're roughly changing the delta between tank and ambient by an average of only 5F during that period. That's 5 of an otherwise 80 delta. Meaning you're only saving about 7% of the STANDBY loss during that setback period.
Given that the standby losses of an electric water heater aren't much of the overall bill, I seriously doubt it's worth the cost and trouble of putting it on a timer. A timer on a seperate electric meter, which some utilities offer, so that you get a cheaper rate because it does the heating off peak, could make a significant difference, if available.
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On Tue, 14 Apr 2009 16:06:49 -0700 (PDT), snipped-for-privacy@optonline.net wrote:

If the OP wants to save money, turn it off and leave it off. Just take cold showers. Bubba
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Here is what you need...
Intermatic EH40 Water Heater Timer 240 vac http://www.rewci.com/inehwaheti24.html
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The savings incurred from using a time clock on an electric hot water heater are from lower electricity costs. Typically, you use an over sized tank, like 80 or 120 gallons, and only allow it to heat during the night, (off peak hours), when your electricity utility charges a lower rate. It's understood that the tank will hold the heat, and as long as your household daily usage is less than one tank, you'll save money
That is true in parts of the world where there are lower 'night time' electrcity rates.
That's how 'storage heaters' may be economic.
Here; in this part of North America anyway, the cost of electrcity rate is the same no matter when it it used. Almost 100% electricity here is generated by hydro power; with a small thermal backup burning Bunker C, with some chimney scrubbers, for peak winter; and during severe ice storms, which might disrupt long transmission lines. The thermal plant is scheduled to be phased out when additional lines and more hydro capacity from the Labrador 'Lower Churchill Project' is available in a few years time.
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Here in NJ, even 40 years ago, JCPL offered a seperate meter that had it's own timer and only provided electricity to the WH during off peak hours at a lower rate. I think there are other areas of the country that are now starting to offer lower rates for off-peak usage too.
I'd be curious to hear if that is indeed what the OP is working with, because I've seen other people here thinking they are going to save some significant amount of moeny by just turning off the water heater over night when they have fixed rate electricity or gas.

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<snip>

catch and yes it DOES NOT MAKE SENSE. It only shuts off for three hours in the middle of the night. I could not believe this, so I called the city utility dept and asked if this was correct and they said yes. I asked if they could reset mine so it just comes on twice a day and was told NO. I talked to the city manager and was told NO that right now that is the way it is and going to be. Like I said "it makes no sense."
As far as saving money with timer. We did a little experiment one time when we went away. We shut the hot water heater off, left several lights on plus the computer and stereo (did not want to leave the tv on) just like if we were home. We then read the meter. When we got home we went and read the meter and figured out what we used. The next time we went away for the same period left everything on like we did the last time plus the hot water heater. There was a significant difference. We were quite surprised.
One thing that now I wish we did when we replaced our hot water heater was to spend the extra money and gotten the high efficiency water heater. A friend of ours has one and put a usage clock on it. All I can say is Wow. Next Time.
Chris
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This indeed sounds strange and is the reverse of what you would expect. The only thing I can think of would be if there were some huge commercial load that comes on for those 3 hours. Not sure what that would be. I have heard of steel plants that use electric furnaces to melt iron that only operate at night because of the reduced cost of electricity.

I'm not surprised there was a significant difference. The procedure you described does not include heating the water back up to the normal operating temperature. So, you are comparing apples and oranges. To get the correct comparison, you should be taking the meter reading not when you first come back, but after you've come back, turned the water heater back on, and allowed it to come back to normal temperature. Then the water in the tank is approximately the same temp as leaving it on.
And the other factor here again, is that the amount of heat loss is driven by the temperature difference between the water in the tank and the ambient air. If you go away for 8 hours, like you would have the water heater turned off with your timer, the tank doesn't cool that much to make a big difference in the rate of heat loss. If you go away for 2 or 3 days, then it can cool enough so that the rate of heat loss has declined quite a bit and turning it off will indeed save a reasonable amount.

All I can say is I doubt the difference among new electric water heaters is that much. Unlike gas ones, all electric ones are 100% efficient at turning the electricity into heat. It's just a simple resistance heating element. The only efficiency differences I can conceive of between electric water heaters are:
1 - Better insulation
2 - Better heat trap on the pipes going in or out.
You can add an insulation blanket to your unit. But I doubt there is a significant energy savings to be had from a "high efficiency" tank type electric water heater.


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