Hot water heater

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iceworm said:
And sometimes it does come in handy to know. Last one I did was a half sized tank fed from a boiler domestic water coil. Didn't use the heater elements. Used the tank heater thermostats to run a circ pump in a return line to keep the tank hot. Was pretty common in areas where boilers and domestic coils are common.

Although not so common any more. Newer mixing valves do a good job keeping the temperature even.

Yeah, I DIY my own plumbing as well.

ice
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Would be a plus to know a little about control wiring to do what you described above or to trouble shoot why your water heater is not working, but, should be unnecessary to know to be able to size a circuit to a water heater.


JAP>
 
jap said:
I'd bet that half's reply would be.." ...
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I got the faith in the everyday electrician.

You're faded. You word and run the pole. Stakes are a cup of yuppie coffee - at the time and location specified by the loser.. Airline tickets and per diem by winner.

ice
 
jap said:
Would be a plus to know a little about control wiring to do what you described above
Yes
or to trouble shoot why your water heater is not working,
Yes
but, should be unnecessary to know to be able to size a circuit to a water heater.
Yes

JAP>
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Still, I'm always a fan of understanding the installation/equipment. Quien Sabe? A question like the OP might come up.

ice
 
jap said:
I'd bet you could poll every electrician on this website and half of them wouldn't know that the upper and lower thermostats of an electric water heater are interlocked.
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I bet you are wrong by a factor of ten. :D


If you have wired or serviced homes with storage type electric water heaters you do know this as do plumbers.

Commercial heaters all bets are off, read the instructions.
 
iwire said:
I bet you are wrong by a factor of ten. :D


If you have wired or serviced homes with storage type electric water heaters you do know this as do plumbers.

Commercial heaters all bets are off, read the instructions.
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I bet your right... .most of them would say " Sure i knew that ???"""":? ...............:)

JAP>
 
jumper said:
The WH usually has two stats, upper and lower, you can turn them up and down and verify current flow with ammeter.
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jap said:
That's probably the norm but common sense would say both heating elements have the possibility to be fired at the same time and should be wired for such.

JAP>
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jumper said:
When the upper t-stat is satisfied, power is then sent to lower stat. Probably relay in upper t-stat.

While the possibility of a malfunction is possible, I imagine the probability is extremely low.
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A little late in joining the conversation here but if the upper thermostat is a "double throw" design, then it is intended to only operate one element at a time. If there should be a malfunction that somehow allows simultaneous operation (though not very likely) you then will have an overcurrent device that sees overload and opens - unless you did run the 50 amp circuit that otherwise wasn't necessary.

Dennis Alwon said:
It is possible that both elements are wired to come on together. IN NC the power companies will not allow that setup for dwellings as far as I know because of the demand it would put on their system.
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Many larger homes around these parts have more then one water heater - instantaneous demand can be higher but can also be higher if there is more then one heater anyway. It still takes same energy to heat same amount of water the same number of degrees at the end of the day. Bigger instantaneous demand issues usually come from a instantaneous type of water heater, but those are a high demand for shorter cycle where tank heaters are lower demand for longer cycle.

ActionDave said:
Even plumbers know the elements on a water heater are interlocked.
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jap said:
Doubtful.


JAP>
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He didn't say all plumbers, but quite a few do know this. Some still get confused with electrical when working on them but do know only one element heats at a time.

jap said:
I'm just pointing out that its not obvious that both heating elements are not energized at the same time, and, if it doesnt indicate that somehow on the label, it wouldnt be far fetched for someone to size a circuit to it for the total load of both elements.


Unlike some who size the circuit for the simple fact they were told both elements dont come on at the same time but seem to have no proof of that without digging into the circuitry.

JAP>
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There is other equipment out there that if you are not familiar with can be just as confusing. These water heaters are simple compared to knowing all the rules and practices related to motors, motor driven appliances, or refrigeration equipment, yet if you are around them a lot some information is stuck in your head and you don't need code book or instructions for every detail because you have seen so much of it that many things are repetition. But you still need to pay close enough attention to catch that one thing that is different once in a while.
 
jap said:
I'd bet you could poll every electriician on this website and half of them wouldnt know that the upper and lower thermostats of an electric water heater are interlocked.
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:happyyes:

In my experience, this is usually because by the time the thermostats go bad, the water heater itself is on borrowed time and it's just better to replace the whole thing.
 
jap said:
I'd bet you could poll every electriician on this website and half of them wouldnt know that the upper and lower thermostats of an electric water heater are interlocked.
Regardless, that's not the infomation that's needed to size the circuit to it.

Jap>
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you and one other would be the first two I've met
 
Cavie said:
If I found a journeyman working for me that didn't know the workings of a water heater he would be fired.
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I myself wouldn't say "didn't know" but rather "couldn't figure out". I work on things that are much more complex then this.
 
Cavie said:
If I found a journeyman working for me that didn't know the workings of a water heater he would be fired.
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If you want to take that attitude I bet I could fire you for a few things that I know that you dont.....


Jap>
 
This is a pretty good image of water heater wiring and how one can't be on at the same time as the other:

Water-heater-wiring-w-num10.jpg

Notice that both elements are wired to the upper thermostat. The contactor in the upper thermostat has one side open when the other is closed, and vice versa.
 
Years ago I broke the law...:D The plumber installed a second water heater in series with the first but to get power there it was going to take digging from one end of the house to the other or piping on the side of the home. Homeowner did not want to do either so I took the last water heater and fed it-- since that was giving the hot water first- then I replaced the bottom element with a spdt ( same as the top element ) . I was then able to run another wire from the bottom out to the top of the heater. From there I ran to the first water heater and fed it from the bottom spdt t-stat. Worked great for these people.

I will probably go to hell for that-- mea cupa.
 
K8MHZ said:
This is a pretty good image of water heater wiring and how one can't be on at the same time as the other:


Notice that both elements are wired to the upper thermostat. The contactor in the upper thermostat has one side open when the other is closed, and vice versa.
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I would almost bet that is the case of this water heater. I have never seen a 4500 watt water heater that wasn't like this.
 
Dennis Alwon said:
Years ago I broke the law...:D The plumber installed a second water heater in series with the first but to get power there it was going to take digging from one end of the house to the other or piping on the side of the home. Homeowner did not want to do either so I took the last water heater and fed it-- since that was giving the hot water first- then I replaced the bottom element with a spdt ( same as the top element ) . I was then able to run another wire from the bottom out to the top of the heater. From there I ran to the first water heater and fed it from the bottom spdt t-stat. Worked great for these people.

I will probably go to hell for that-- mea cupa.
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Never thought of that, but have no problem with it either. If you run out of hot water with that setup something isn't working or you are using an awful lot of hot water all in a short time.

In fact the more I think about it the more sense it makes to me to do that if the plumbing is in a series through the tanks. Running separate power to each tank is necessary if the tanks are in parallel though.

Geothermal heat pumps usually have a water circuit to dump heat into domestic water heating system - and a similar series of tanks with the heat pump pre-heating the first tank and second tank being normal electric heat elements is the most efficient way to connect those. During summer months when heat pump runs a lot - you can get nearly free hot water as the normal elements don't need to run that much - depending on water usage habits of course.
 
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