how could a water heater malfunction make an electric bill double?

Great Q!

I've no answer, except that it could be the inefficiency of operating with only one element (the other with an open), but do to the "only one element is energized at a time" deal, I can't picture how a multi-element heater is any faster or more efficient than one with only one working element...

Anybody have the ability to explain this in a way that my little brain can comprehend?

The first thing that springs into my mind is the possibility of a faulty thermostat, as this seems to be a common problem here.

I would think that somebody would notice the excessive water temperature though.

First, the obvious. Are there any leaks in the water pipes? HAs the cold water dip tube broken off?

I suppose it is possible that one of the elements may have a hole in it, but that usually results in a rapid element failure.

Why is the water heater being blamed? Could be plenty of other electrical problems involved that don't include the water heater.

I do metering work for a power company, so just a quick calculation, assuming a $100/mo bill increase & $.10/kwhr, that comes out to 1000 kwhrs. or approx 33 kwhrs/day

If the H2O tank is the culprit, then the water either must be very hot (stuck thermostat or grounded element) or the Pressure Temperature Reief valve is releasing the hot water & allowing the water to reheat over & over. To see if it is the second, see if the PTR valve is permanently plumbed to a sink or outside & if so insert a small peice of cloth into the end & check the next day, if the valve operated the cloth will be blown out.

I do hot water tank servicing as part of my job duties & I do not see many high usage problems with H2O tank being the culprit that don't generate complaints that the water is too hot.

If your bill doubled, you should call your local power co & have them reread the meter & if still high test the meter.

Also, the speed of disk in the meter is a very good indication of electrical usage for any given moment. You should periodically check the speed of the disk & if it is spinning fast, start turning off breakers to see which circuit it is on. Once you have the circuit figured out determine if the usage should be expected, in the washer or refrigerator running etc. (This is a good trick for home owners, who do not have clamp-on ammeters avaiable.)

I have seen alot of direct bury feeds to garages & pools be the cause of high bills, due to the insulation on the live leg being cut & the energy being bled off into the
ground.
I hope this helps.

[This message has been edited by ameterguy (edited 05-17-2002).]

a friend asked the question without giving particulars and i haven't seen him since he asked. he just said he turned off all the breakers when the meter started spinning and turned them on one at a time to find the problem. i didnt have time to ask questions so my 15 second answer was to check the elements and call me in the morning. if its too hot, or leaking, that should be easier to troubleshoot.

but does anyone know what happens in terms of power consumption if an element burns out? will the watt useage increase? seems like it should still operate on 240 if one element goes out. cold water enters the bottom of the tank through the dip tube and the hot water rises, so if the top element goes bad does the top or bottom thermostat keep telling the bottom element to heat up? one element only uses half the power, right? so if it had to work twice as hard to compensate for the other one, twice as much work for half as many elements should roughly balance out, assuming the efficiency of the upper/lower design wasn't a way big deal. if the problem was running out of hot water it might be the lower element isnt helping, but that would mean that it shouldnt use as much power because it is only heating the upper half, so this one doesnt seem likely to increase power consumption either.

so i'm going with the sticking thermostat if its too hot. or the leaking hot water. the grounded element bugs me though. are you saying it could be using/losing power like in a short circuit?

i might be confused by the terms here.
grounded element?
element burning out?

2,3,4,5,? little brains are better than one...Virgil??

methinks the plumbers use the 'stratify' term here, or in that the top 1/2 satisfy's the t-stat until flow/usage
possibly Cindy,,,.....
a burnt/exposed element will not necessarily trip the serving breaker,it may pass current to ground and use up the juice while providing poor hot h20 performance.

the bottom element , given water quality, may go first. i see this from shallow wells, lots of junk rots it out.
meter out your elements first, they are commonly the'weak' link.....

LOL meterguy , the melted snow is a dead giveaway ( pun intended...)
LOL Tom, how about a tank with no jacket in a leaky old stone farmhouse basement in the winter, no furnace there either....

Two things pop into my mind....

1st shut the main off to your house, see if your meter stops turning if it does great if it doesn't you could be getting a feed back from one of your neighbors homes.

The other thought is these meters need calibrations every so often

Cindy, look for simple things first.
probably has leak in hot water somewhere,I found a humidifier once with stuck valve running hot water continuously.

Water heater thermostat-- Upper thermostat heats top element till satified then switches to bottom thermostat. If bottom element fails you will only get half capacity of tank, if top element fails you get no hot water (top therm. is never satified so it doesn't switch to bottom). Had one once where element shorted to tank and kept heating(therm. is only single pole)
Moral of story, keep lookin'


Glenn

Cindy,

I agree that if you lost say the top element, it wouldn't double the bill. It takes so many BTUs to raise the water to the required temperature, so if the electrical input power is reduced it just takes longer to get there while using near-enough the same amount of power. Lose the bottom element and you may just get a smaller amount of hot water as the top thermostat cuts out before the whole contents are hot due to hot water rising.

If you had an element shorted to ground mid-way, then instead of one element connected across 240V you'd effectively have two elements each running on 120V. I'm not sure if your thermostats are single or double-pole, but if SP then the side of the element not on the thermostat would keep running continuously even after the 'stat opens.

I was leaning towards the leaky hot water pipe / faucet idea first - since it's the most logical [per Mr. Spock! He is a Plumber, 'ya know ].
This is usually coupled with an almost coincidental increase in water consumption!
I headed this way due to many, many Tshoot Q's and trips concerning high KWH consumption and resulting water consumption!

If the leaky bugs are not to blame [AKA no leaks], then try "Step 2", which is to verify the T Stat is operating properly and that no one has set it to "Boil" [AKA the highest setting].
Cannibals may prefer the "Boil" setting <joke>

If still a head scratcher, make sure the culprite for the increased KWH usage is indeed the water heater [so you don't tear it apart and your friend walks in and says "Oh, I forgot to mention the outside lights that stay on 24/7!"].

If all signs point to the water heater, check the elements for leaks [electrical leaks] and the correct wattage.

If all these points fail to turn up a culprite, hire an Excorsist!

Scott S.E.T.

LOL!
yeah, 'specially if there's any split-pea soup around.....

he changed the thermostats and the problem went away..... solved

10 points to the thermostaticly inclined posters....

one thing that nobody said was that in call for heat most double element water heaters the top element is put in series with the bottom element untill the top reaches the set tempature and the it closes and puts all the power to the botem element then when this element reaches the set tempature it opens its contacts and shuts of the water heater. this is why when you look at the rating on the heater it will say the upper element 4800 watts and the lower element 4800
and the total is 4800 watts is still the same because of the two elements are only in series with each other. thus lowering the voltage to the two elements to 120 when it calls for full heat. so you have to have the top thermostat set a little higher then the lower one or it will use a lot more electric.
I have had people set the top thermostat to low and since the bottom element kept trying to heat as the water would rise to the top it would take longer to come up to tempature and also use allot more power.
But I have had some that when the top element failed it did the same thing.

:Wayne

[This message has been edited by hurk27 (edited 05-25-2002).]

Ahhhh------ Earth calling Wayne, you might want to go back and look over those wiring diagrams

Glenn

Glenn your right I did check the new tank that I now have and it is a non simultaneous type the old colman that was in there was wired so that when the top thermostat called for heat it would put both elements in series with each other but when it shut off the botom element would get full power. with this one when the top element is on it disconects the power to the bottom one. the botom element cant come on until the top goes off. didn't know there was diffrent ways they wire water heaters. I guess I can chock one for another learning experance lol
:Wayne