OT- Water heater question

[Jrry]

I have a 40 gallon electric water heater that is about 4 years old. It is rated for ten year life. Recently it has begun shutting off during the day. I can push the reset button that is in the door by the top eliment and it will work for about 12 hours and shut off again. We have noticed that the water temp is getting much hotter than it used to. I turned the setting down but it still gets just aas hot.I thught it was an electrical short but i had an electrician check it out and he said no problem there. He thought it may be the thermostat. If the problem is the thermostate not working properly then how does it determine that it needs to shut off? If is is the thermostat are they difficult to replace or should I just replace the water heater? I know this is off topic but there are knowledgeable people here about most subjects. thanks for any help, Jerry

 

[Anonymous-0]

Can't be anything difficult (after you get over the "it's a major appliance" intinidation). Check out the tankless heater post a little farther down, someone mentioned a water heater repair kit w/ tstat and a couple of other things. Or, just take the info off the plate and go shopping. While you're playing with a screwdriver, may not hurt to pull the elements out and clean some of the lime off.


Dave

 

[paridgerunner]

Thermostat's are easy to replace and cheap, I would try to replace them before buying a new water heater, just shut the power off before changing them.

 

[Ken Crisman]

I'd guess elements first , than bottom thermastat . I had the very same problems . Found the bottom of my tank had about 3" of iron buildup laying around the element . Flushed it out as best I could & then replaced both elements since iron buildup was so bad . Than I decided to go ahead & replace the bottom therastat also . Walla ! My tank ststed to replace the bottom element with a higher element so I did . Boy I have much better hot water now . So check out to see if yours states to do that before buying parts . HTH! God bless, Ken

 

[KEB1]

Most likely the bottom thermostat. There should be two thermostats, one at the top and one at the bottom. The top thermostat also acts as an overtemp limit and will shut both elements off.

If the bottom thermostat is stuck on, or not making good thermal contact with the tank, it will keep the bottom element on until the water gets hot enough to trip the overtemp limit on the top thermostat. Tripping the overtemp on the to thermostat shuts off both elements, so you have nothing to heat the water until you reset it. 12 hours is probably about how long it takes the bottom element by itself to get the water hot enough to trip the overtemp limit switch.

Its also possible its the top thermostat, but I'd start with the bottom one.

Keith

 

[Bob]

It's either a thermostat or an element.

Thermostats can stick.

OR, if an element (usually the lower one) fails in such a way that part of the element becomes grounded or exposed to the water, the heater will SLOWLY overheat... 'til the limit switch trips.

This happens because the thermostat only breaks one "leg" of the 240 Volt line. The element is ALWAYS connected to the other "leg", 120 Volts, even with the thermostat open, so if there is a short or damage to the element, it will keep heating.

When the safety limit finally trips, it breaks BOTH sides of the 240 Volt supply, so the overheating stops.

 

[Duner Wi]

When I have trouble like yours it is my lower element. Last one I put in was called a Sand Hog I think and has lasted many years.

 

[Walt Davies]

check your warranty and see if its covered before spending hard earned money.
Walt

 

[HENRY E NC]

Most hot water tank thermostats had a thermodisc cut off which shuts it off should the thermostat fails to shut the electric off.. Change one or both of the thermostats and you will be good to go. Henry

 

[buickanddeere]

Get a new electrician.
An element is grounding out and putting full time 120V through part of the element, bypassing normal thermo control until the overtemp thermo trips.
Imagine what would happen without a properly bonded and installed grounding system. There would be somebody shocked, injured or dead after touching the system or showering.

 

[Anonymous-0]

1) Both upper and thermostats must be set the same
(usually 120 degrees) (do not set them at different
temps for any reason as this is the balancing device(s)
for temperature in the tank itself. before this make sure
bottom of tank is not full of sediment and flush as
necessary via the lower element when removed (first
shut off the electric power to the heater and keep it off
until the tank is full of water again and air is bled from it
via a faucet or the relief valve vent )... then inspect
condition of lower elelment (no resistance or very little
on an ohmeter if you have one available. I don't think it
is a non touching thermal disc because it was okay for
some time before the overheating problem began,
however it could be bad though... Bottom unit as a
whole is where i would start and probably find the
problem(s). Remember --- electric off when working on
this heater especially when you are draining it and
refilling untill entirely full of h2o and all air
removed(bled).