Water Heater Elements Going?


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Old 12-05-09, 10:49 AM
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Water Heater Elements Going?

I have a 2005 era, 80 gal, 9K watt (4500w top, 4500w bottom element) GE water heater. I am draining the water heater to move the unit a little to fix a faulty whole house shutoff valve and make room for a whole house humidifier. Due to the amount of cool water coming out of the unit, I'm concerned that one of the heating units is not working.

Specifically, when draining the unit, all of the water from the bottom of the unit came out room temperature. Once the unit was half drained, warmer water started to come out - but still not hot.

I checked the resistance on both of the heating elements, and the resistance is ~40% on both (the ohmmeter goes to .4 ohms, or just past the halfway point on my analog voltmeter). I expected 0. Are both units bad? I thought it would be 0 or 1?

To be honest, there are just 2 of us in the house, and there isn't as much hot water as there used to be.

The thermostats are both set to 135 degrees.

Thanks!
 
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Old 12-06-09, 08:40 AM
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You want the upper thermostat set lower than the other.

Only one heater element is switched on at a time.


You want the upper element on in the presence of low water temperatures, to heat up the water at the top for use right away.

When that bubble is heated, you want the lower element to switch on to heat up a full tank of hot water.

If you set the upper t-stat at 120 degrees and the lower t-stat at 130 degrees, you will accomplish these purposes.

If you have both set at the same temperature, the upper element may be the only one that winds up turning on as you describe.

If you want to test a heating element with an ohmmeter, disconnect the power to it so that you avoid the possibility of having something else in the circuit when you test ---and have the power off, of course.
 
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Old 12-08-09, 04:13 PM
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I have the upper set 5 degrees below the bottom unit, but I'll decrease the upper unit by another 5 degrees.

Regarding the resistance across the element, I have 4 ohms. (and yes, the power was off when I tested.)

What is expected?
 
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Old 12-08-09, 05:26 PM
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(240^2)/4500w = 12.8 ohms.
 
 

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