Reset button popped


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Old 01-12-14, 11:35 AM
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Reset button popped

5 year old AO Smith electric 50 gallon unit had no hot water today. Removed thermostat cover and found reset button popped. Reset and now working.
What is the most likely cause?
About 3 months ago the water seemed a little hotter than normal but cleared up by the next day
The heater is flushed and T&P valve operated every 6 months.
Thanks in advance
Bart
 
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Old 01-12-14, 12:56 PM
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shut down the electric and tighten all the connections within then all the way back to the CB panel for the heater.
 
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Old 01-12-14, 02:58 PM
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Bart, did you adjust the heat? It could have been set too high. Keep an eye open and let us know if it repeats.
 
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Old 01-12-14, 03:52 PM
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Haven't touched the thermostat temps in years. I have 3 lovely adult females living with me and the last thing I need is another text claiming no hot water!
 
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Old 01-12-14, 03:57 PM
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I just would want to prevent scalding, but if the women are happy........keep an eye on the reset.
 
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Old 01-12-14, 05:09 PM
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You more than likely have a heating element going bad. Usually it's the bottom one. That safety is tripping on water that is too hot. If the problem happens again plan on changing at least the bottom element.
 
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Old 01-12-14, 06:53 PM
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You more than likely have a heating element going bad. Usually it's the bottom one. That safety is tripping on water that is too hot. If the problem happens again plan on changing at least the bottom element.
Yes, it could be because the lower element going out, but the lower element is controlled by the lower thermostat. The water getting too hot could be caused by either the lower element going out or the lower thermostat going out. That being said, the elements usually fail more often than thermostats. Also be advised, the reset is a manual high temperature limit switch, most are made by "Therm-O-Disc" and are marked "TOD". Once the limit starts tripping they get weak and will trip quicker than the time before. Once the limit has tripped 3 or 4 times, it probably should be replaced along with whatever was causing the trip in the first place.
 
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Old 01-15-14, 04:32 PM
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Reset button still has not popped again, but did notice the water wasn't that hot today. Both thermostats are set at 140f. Water temp at kitchen faucet was 115. I just raised them like 2 degrees and they clicked and I heard the upper element start hissing a little. Now the temp is 132. Think I have a faulty stat? I have no problem replacing both stats if that is it.
 
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Old 01-15-14, 05:18 PM
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If you think it is the stat, first make sure the cradle for them holds the stat tight to the tank. I have seen where people have pulled stats and deformed the bracket ears. Just thinkin'
 
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Old 01-15-14, 05:27 PM
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I would have to say that they appear to be firmly mounted. Thanks
 
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Old 01-15-14, 05:28 PM
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Think I have a faulty stat? I have no problem replacing both stats if that is it.
I think I'd replace the top thermostat and high limit, they often come together in one blister package. The top thermostat is the brains of the whole heater and directs power either to the top element or to the lower thermostat. Without the top thermostat being satisfied, the lower element will never come on. Pay special attention to what Chandler just mentioned too.

make sure the cradle for them holds the stat tight to the tank
Both thermostats must be mounted so they are flat on the tank. They must sense the water temperature through the steel wall of the tank.
 
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Old 01-17-14, 05:54 PM
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I replaced the upper stat today and all seems good. Temp set at 140 and temp at faucet 135. $27.00
 
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Old 01-17-14, 07:11 PM
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$27.00
I haven't bought a thermostat in quite a while, but didn't think they would be that high. Where did you buy it, what brand was it? Regardless, if it fixes the problem it was worth it!
 
 

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