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Old 05-06-2009, 07:23 AM   #1
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Hot Water Suddenly too Hot

I have a GE 2 filament electric hot water heater. The unit is less then 3 years old. Suddenly yesterday evening, without intentionally changing anything, the hot water temperature increased dramatically. We even got a bit of steam spurting through the lines.

I read through posts on the internet about this problem and I am assuming it is a thermostat problem, though I have not found a good way to prove this theory out completely. I have purchased 2 new thermostats and intend on installing them, but would like to understand the problem better.

I am additionally concerned because the high temp limit switch did not trip nor the relief valve. Should they have with steam in the lines? I would think so.

Any help would be greatly appreciated.


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Old 05-06-2009, 09:04 AM   #2
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If steam was present, I would have thought the T/P valve would have opened. My water heater is set at 120 degrees and, depending on the ambient temperature of the room, at times it can appear that steam is coming out of the showerhead.


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Old 05-06-2009, 11:17 AM   #3
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I have heard of WH thermostats developing dead spots. If you turn the temp all the way up and down a couple of times then set to proper temp it may take care of the problem.
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Old 05-06-2009, 12:37 PM   #4
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One of the filaments (elements) is not shutting off and the water is overheated, in this case to the boiling point.

You cannot leave the heater running in this condition without the danger of building up so much (steam) pressure as to cause an explosion. Summarily replacing both thermostats and also the pressure relief valve would be a good move on your part. Before that, switch off the power when no one is using hot water. Turn it on only when needed, an hour in advance while trying a hot water faucet every now and then to check for unusual pressure in which case turn it off again.

Someone with electrical know-how can test the old thermostat by boiling it in a pot of water.
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.

Last edited by AllanJ; 05-06-2009 at 12:41 PM.
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Old 05-06-2009, 12:43 PM   #5
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You are doing the right thing in replacing the tstats and the T&P valve.
As you may know, get new tstats that look exactly like the old ones (do not have to be same brand) with the same layout and number of screws.
Switch the wires one at a time from the old to the new tstats, and you can't go wrong.
Good Luck!
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Old 05-06-2009, 05:59 PM   #6
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you should also be prepared to replace one or both elements. This can be a symptom of an element shorting out as it is going bad or corroded.
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Old 05-06-2009, 08:24 PM   #7
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check the temp of the water . Anything around 200- 210 deg. T&P should begin to open.
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Old 05-07-2009, 08:24 AM   #8
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I replaced the 2 thermostats yesterday evening and set the temperature low ~ 100F. I did this to ensure that I could tell if the controls were working properly. Things appear to be more or less back to normal. The water temp has come down for sure but I did have a little air in the lines still this morning - hopefully this is just a remenant of the original problem which has not cleared the lines.

Thanks for the input.


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hot water heater , thermostat , water too hot

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