Hot water tank.....question

[General Lee]

I noticed this evening the hot water at the faucets is much hotter than normal. Last time I adjusted the T-stat was probably a year ago and I checked to make sure they were still set where I had them.....they were. I have the T-stat set at approximately 140 degrees.....main purpose is for the dishwasher. I just took a temp reading from the faucet....its 160 degrees. Whats going on here....T-stat not working right or the heating element(s)?

 

[beenthere]

Electric hot water heater, oil , or gas?

I'm suspecting electric. But I'd try turning the T-stat down and see if the temp of the water drops accordingly.

 

[General Lee]

Electric hot water heater, oil , or gas?

I'm suspecting electric. But I'd try turning the T-stat down and see if the temp of the water drops accordingly.

Sorry, electric. I turned the T-stat down, I guess we'll what happens.

 

[Grayson Klassen]

One possibility is buildup in the tank either as sediment or crust. Do you have soft or hard water?

 

[crash325]

One possibility is buildup in the tank either as sediment or crust. Do you have soft or hard water?

I'm building a stove, 4th one, out of a hot water tank. This tank was gas, but the first 3 were electric. All the tanks had a lot of build up on the sensors and / or heating elements. This last tank was the worst. There was at least a bucket (2.5 gallons) of sand and minerals in it. One of the sensors was a just a huge blob. There was really nothing wrong with the tank other than the crude inside.

I recently changed a heating element on another tank, same thing, build up of minerals.

If about once a year folks would open the drain valve on the tank and let it flush out the crud the tanks would last a lot longer. But don't try that on an old tank, as it may never shut off or work right again.

 

[General Lee]

One possibility is buildup in the tank either as sediment or crust. Do you have soft or hard water?

I would say the water is more on the hard side but not to bad. I would think to much build up or sediment would cause it not to heat sufficiently (not enough). Just out of the blue, its heating to much.

 

[crash325]

I would say the water is more on the hard side but not to bad. I would think to much build up or sediment would cause it not to heat sufficiently (not enough). Just out of the blue, its heating to much.

Build up on the heating element will slow down heating. Build up on the temp. sensor is like insulation so it takes it longer to feel the heat in the tank.

 

[General Lee]

Build up on the heating element will slow down heating. Build up on the temp. sensor is like insulation so it takes it longer to feel the heat in the tank.

So a possibility is build up on the T-stat and as the water continues to heat the T-stat is not registering it? and water temp continues to rise? So far it hasn't tripped the high limit switch.

 

[hr3]

The T Stat is on the outside of the tank on most electric water heaters not in the water stream and are known to be not very accurate.. Make sure you turn down "both" T Stats the same amount..

 

[gunnyad]

The top t- stat controls the time/temp the top element heats ,the bottom t-stat controls the bottom element heat but will not heat as long as the TOP.needs to run to SATISFY its temperature.,because you draw water off the top . You can amp probe the elements about 15-17 amps depending on element watts. You must satisfy the top t-stat temp ,to get the voltage to switch to the bottom t-stat to amp probe it.adjust setting to turn on/off element. I always use the clip over wire amp probe, both amp readings should be the same when heating. weird reading ,bad element.
bottom element usually is the bad one. in your case sounds like the top t stat bad.
make sure the top element has heated enough to switched voltage to the bottom element and the t-stat calls for heat on the bottom element to amp probe the bottom element. there should be power to the bottom element to amp probe it.
be safe just my way of doing it.