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no hot water

Posted by arkreb68 (My Page) on
Sat, Feb 1, 14 at 14:47

I replaced the lower element on my electric water heater, now I'm not getting any hot water. checked the breakers, it's getting power confirmed with tester, but still no how water


Follow-Up Postings:

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RE: no hot water

It helps to understand how an electric water heater works:

From a cold start, the upper element heats until a set point, thereby getting some hot water to the top of the tank where the hot water outlet is.

once the upper thermostat is satisfied, the upper element shuts off and the power is sent to the lower thermostat and element. When the lower thermostat is satisfied, the heater shuts off.

A thermal safety will shut off all power to the tank if the water gets too hot. Once activated, the thermal safety stays off until manually reset.

A common mode of failure is that the bottom element gets covered in lime and sediment. Without water to keep it cool, the element will burn out. Often times when this happens, the element actually melts and breaks. If this happens, the element can then form an electrical short to the lime and water to the metal tank, which is grounded.

Since the thermostats are usually only single pole, one leg of the 240v power is on -so a shorted bottom element can in effect be on constantly at 120v.

This type of failure will show itself as VERY hot water after there has been little water use... and/or the hot water runs out quickly.

This can continue until the thermal safety shuts down all power.

So... to answer your question: If you replaced your bottom element be cause it failed in the above manner - check and reset your thermal safety. It's a red button.

If that doesn't solve the problem, your top element may be out (if it's burned out, the upper thermostat will never switch to the bottom element). The upper element usually burns out because the power was turned on to the tank before it was completely filled (and burped of any air at the top).

Understanding how the heater works, you should be able to test with an electrical tester for 240v at upper element... if you have it and no hot water, then your upper element is bad. If not, check your thermal safety switch and upper thermostat.


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RE: no hot water

The red button is at the top thermostat.


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RE: no hot water

Curious, we seem to have a new "situation"- in the Master Bath, both the tub and shower get hot water fine, but when we add the cold to it, instead of being moderately warn/hot it's actually mostly cool. Turn off the cold water and it's quite hot. Any clues what is going on? (sorry if this is bad form or hijacking a thread).


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