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Posted by Don Young on September 18, 2006, 11:26 pm
> Hi everyone. I hope someone can helo me with this as I am baffled
> beyond imagination here. I have an electric hot water heater that
> burned out the bottom element. I opted to replace both elements and
> thermostats since this was an in-expensive investment.
>
> So replaced both upper and lower elements, upper and lower
> thermostats..and still no hot water.
>
> one thing I did do is buy another set of elements and when I removed
> the first set, I noticed that only the edges were getting hot and not
> the entire element..could it be the I need to adjust the thermostat to
> a higher temp?
>
> Also, I checked all electrical wiring and I have voltage everywhere its
> suppse to be.. Also did a resistance test on all 4 elements, first set
> and second, and all pass with flying colors..
>
> So I am confused and not sure where to look next...
>
> This is a 240 volt system and both leads are hot..checked and verified.
>
Your post is a little confusing because if you have proper voltage across
the element and the element resistance is correct, there is no way it will
fail to heat.
When you say both 240 volt leads are hot, do you mean they have 240 volts
between them or that each has 120 volts to the neutral or ground? If the
latter, and the leads are connected to the heater, you can have one fuse or
breaker open.
With everything connected normally, test for 240 volts across the input
leads. If present, test for 240 volts across the element terminals. Do not
confuse yourself by making any measurements to neutral or ground.
If you have 240 volts at the input but not at the elements, one of the
thermostats is open or something is miswired. Most dual element heaters only
operate one element at the time. From cold, the upper element heats until
the upper thermostat gets hot enough to switch. The upper element then turns
off and the lower element is switched on, both actions done by the upper
thermostat. The bottom thermostat will still be cool and its contacts will
be closed. When the bottom element heats the water hot enough for the lower
thermostat to switch, it will turn off the bottom element.
Most of the heating is then done by the lower element, the upper element
only coming on when the top of the heater gets cooled down by using a lot of
hot water. It will help to understand this to know that the cold water goes
thru an internal "dip tube" and actually enters the heater at the bottom.
Your big mistake was in replacing the upper element and the thermostats
unnecessarily, but you should be able to get it going again if you
understand how it is supposed to work.
Don Young
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