Electric water heater

[farmer boy]

It's a 40 gallon heater than was working fine up till yesterday. I come home to find that there's no hot water and the breaker is tripped. Turned it back on and 1/2 hour later it trips again. Dims all the lights in the house while doing so.(100 amp service). I tested the resistance of the elements, and both tested at 19.5 which seems right. It's 240 volt with 3000 watt elements. I measured power at both elements and both were getting full power. Measured resistance and it was 0 and 19.5, depending on which wires you compared. Has the top thermostat failed and allowed both elements to heat? That's all I can figure out but am not sure. TIA

 

[Anonymous-0]

Sometimes ignorance is a blessing.......... In your place, I'd unhook one and try the breaker...... Try that until an expert comes on and tells you what to do.... I bet an element is the problem tho...

Dave

 

[DaveK(IN)]

When you say "power" I"m going to assume you mean voltage. If you are getting voltage at both elements then your themostat/switch is bad. Pretty uncommon but the parts are at the hardware store. It is designed so ONLY ONE element can be energized at the same time. If they are both running your breaker would trip fairly quickly since the load would be doubled to 6Kw.
HTH

 

[farmer boy]

Yes by power I mean voltage 248 volts.

 

[Ron Grother]

get rid of it and get a new one. time you play with it. new parts. running around you will have the cost of a new one

 

[old]

Almost bet your lower element is sitting in a lime stone quarry and that is what is causing your problems and it is going bad plus the lime does not help either. Ya BTDT a few times and 95% of the time it is the lower element

 

[buickanddeere]

(quoted from post at 16:50:34 08/26/11) It's a 40 gallon heater than was working fine up till yesterday. I come home to find that there's no hot water and the breaker is tripped. Turned it back on and 1/2 hour later it trips again. Dims all the lights in the house while doing so.(100 amp service). I tested the resistance of the elements, and both tested at 19.5 which seems right. It's 240 volt with 3000 watt elements. I measured power at both elements and both were getting full power. Measured resistance and it was 0 and 19.5, depending on which wires you compared. Has the top thermostat failed and allowed both elements to heat? That's all I can figure out but am not sure. TIA

Isolate the power leads from the heating elements. Measure ohms from each heater terminal to chassis. There should be no path but as previously stated. Odds are the bottom element is shorted.
Time for a water softener and a new heating element.
Be glad the ground held or somebody using water could have been shocked.

 

[onefarmer]

Yep 99% chance it"s the lower element.

I got an extra 10yrs out of one by removing the element and digging the lime out as much as I could. Didn"t need to be perfect, just away from the element and allow for some more build up.

 

[farmer boy]

So I powered just the lower element and it didn't work. Took wires off and checked resistance, and it was at full resistance and the thermostat was supplying top element only. Not sure why that happened, but it looks like the bottom element needs replacing. Top element is now heating the tank.

 

[Anonymous-0]

You'll prolly find enough chalk sludge in there to do the lines for a ball game. Good time to suck it out and buy you a few more years.....

 

[IOWA NORTHEAST]

We have limestone a mile deep here. That problem is a everyday thing. I disagree about replacing it and not fixing it.

The element may come out hard, but just tear it out if you have to. The lime makes it not cool down, and it then will burn out. If you sit a new element on top of a work bench and power it up, it will burn out in less than a few minutes.

A little trick is to take a bent piece of 1/2 inch rebar three foot lomg and pull the lime out ...AS... you let the water out of the element hole. It will certianly help by flushing the lime out as you pull it towards the element hole.

Flushing one or twice a year will keep it good as new. If it is rusted at the bottom, then consider replacing the whole thing.

Many homes with only a single person can get by with only one element.

 

[Charles (in GA)]

DaveK(IN) has it right, the bottom element does all the work in normal circumstances. The only time the upper element comes on is when you have nearly exhausted all the hot water. When that happens, the upper thermostat sees the top of the tank cold, it shuts off the lower element and turns on the top one in an effort to get you some hot water fast. When the top of the tank is hot, the upper thermostat shuts off the upper element and the lower thermostat, which is still cold, begins powering the lower element till it is satisfied and then everything is off.

I'm actually surprised that the breaker takes as long as it does to kick off with both elements working at one time.

Charles

 

[huntingreen2day]

You can read resistance on a bad water heater element. I always use a clamp on amp meter along with a VOM to check water heater elements. If you have 240 volts at the element it and no hot water it has to be the element.

 

[buickanddeere]

What is "full resistance" ?
Resistance measured across what?

 

[buickanddeere]

Why live that way?
Install a water softener and get rid of the minerals. Before water heater, shower heads, tea kettle, dishwasher are scaled up.
Saves a lot of soap usage too. Better yet, less soap for the septic system to handle.

 

[farmer boy]

Measured across the terminals of the lower element the value on the meter never changed(stayed at 1)

 

[buickanddeere]

Is the meter on ohms and the leads plugged into the ohms sockets?
An ohm meter should not read " 1 " without a circuit between the probes.
The meter should swing the needle from a full scale high number, down to approx 0 ohms if the probes are touched. Infinite ohms if apart.
This appears that terminal to terminal on the heater element is "open, very high resistance, no path" ?
What does the meter read when measuring to the outer sheath of the element that is grounded to chassis. To one then the other power terminal on the element?

 

[DH in Carolina]

Not to argue with you but what you say is true if using an analog meter such as a simpson 260. If using a digitial meter such as a Fluke 87 the reading would be OL with leads not connected to anything. Connected the reading would go to "1" showing that the element is reading "1" ohm or less and is shorted. We don't know what meter he is using or the range setting he is using. DH

 

[El Toro]

If you have natural or LP gas available I would switch to gas. I've used gas since 1954 when I was in the Army. We even had it at home before I was drafted. Hal

 

[farmer boy]

It's a cheap digital Mastercraft meter. It reads 1 at the far left of the display when nothing is being tested. If it were 1 ohm it would be at the right of the display. Neither terminal is grounded to the chasssis. I think what may have happened is that the top thermostat was allowing power to both so when I tested the bottom element(with all the wires still connected as they were) it actually gave me the resistance of the top element making it appear as though the bottom element was fine. I have disconnected the bottom element from the thermostat and now the thermostat seems to be operating normally.(even if bottom was connected it wouldn't be getting any power).

 

[buickanddeere]

located where in Canada?

 

[Gary from Muleshoe]

If it trips after a period of time then it is most likely the bottom element. I have had similar problem and changed the bottom element and it fixed the problem. While you are at it you may as well clean it out while you have the element out. Water deposit build up is what causes the element to burn out. I always clean them with a shop vac and a piece of 3/4 pvc taped to the hose. You won"t get it all but you can get 95% of it.

 

[tomNE]

clean ur tank twice yearly and your problem is solved!

 

[buickanddeere]

Why go treating the symptoms twice a year? Install a water softener and rid of mineral build up. Less household use of soap too.

 

[farmer boy]

Markdale, ontario

 

[tomNE]

no place for water softening system; had culligan here to make the sale; no usable spot. anyway; thanks for the reminder; drained mine today while taking a break this afternoon. it was time.

 

[buickanddeere]

Ah yes, the home of Chapman's Ice Cream.
Drove through their last weekend on the way to Camp Borden. Used to attend the Fur and Feather meetings at the municipal building there too.

 

[Earl Gray]

Guess again, 95% of the time it's just the bottom element which costs $10-$15 and are usually easy to change. A new heater costs $300, no wonder some people are broke all the time.

 

[Russ from MN]

We didn't have room for one at our cabin either, so I dug a hole in the dirt in the crawl space and buried one with just the upper half sticking out. I put the brine tank next to it and it works great, not real handy to put salt in but it doesn't use much anyhow. I would quite talking to Culligan as you just pay a lot for the name and the units are all about the same anyhow.

 

[36 Coupe]

Get rid of the blinky digital meter.An analog meter wont respond to spook voltages.The lower element could have burnt a hole in the sheath.This will energize the water .Be careful with water heaters , they have dual fuses or circuit breakers.A do it yer selfer was elec trocuted working on a water heater here.