Are both heating elements supposed to go on the same time

Copy following link for tank-type electric water heater troubleshoot:
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html#skyrocket

Press reset button located on upper thermostat.
Test elements for short to ground against steel tank.
Clean sediment out of tank. Check for water leak running hot water out of tank.
Replace both thermostats.
http://waterheatertimer.org/How-to-replace-thermostat-on-electric-water-heater.html

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see this causes and fix it. God bless you
Heating Element A defective heating element can make a dryer too hot. If the element partially shorts out, it can produce heat all the time, regardless of whether the dryer is calling for heat. Remove the heating element to inspect it. The coils should not be touching each other or anything else.

Heating Element Assembly A defective heating element assembly can make a dryer too hot. If the element partially shorts out, it can produce heat all the time, regardless of whether the dryer is calling for heat. Remove the heating element assembly to inspect it. The coils should not be touching each other or anything else.

Air Flow Problem Dryers need good ventilation to work properly. If the vent is clogged it can make the dryer too hot. Clean all of the vent tubing thoroughly.

Cycling Thermostat Although not common, a defective cycling thermostat can make the dryer too hot. The cycling thermostat is supposed to turn on and off the heat to maintain the proper temperature. If the thermostat is defective it may keep the heat on too long. The thermostat is not adjustable or repairable, it must be replaced.
Felt Seal Most dryers have a felt seal at the front and rear of the drum to keep the heat inside the drum. If the felt seal is worn away or missing, the dryer may keep heating and make the dryer too hot. This is not common.

Blower Wheel A defective blower wheel will not spin properly and will not vent the hot air, making the dryer too hot. Check to see if there is adequate airflow out of the dryer.

The top element should be heating if there is 240 volts across the element terminals. I take it that the top element is the booster element. The thermostat for the top element is normally a 2 pole thermostat which switches the neutral to the bottom thermostat once it reaches temperature. Once this occurs then the bottom element will start to heat. The top element will only come on when you use all the hot water. Is this supply on the off-peak rate? When testing always check the voltage across the element terminals.

Most electric hot water heaters have two thermostats, one near the top of the tank and one near the bottom, and are covered by removable metal cover plates. The thermostats are pressed firmly against the bare metal wall of the hot water heaters tank.

The top thermostat usually has a high limit switch that will trip if the water gets too hot. When it trips it shuts off the electricity to both the upper and lower heating elements.

To reset the high limit switch there is usually a red button that you must press. When the upper limit switch trips it is often an indication that something else has gone wrong with the heater.

When the top of the tank is hot the upper thermostat removes power from the upper heating element and transfers the power to the lower thermostat and heating element. If the lower thermostat is defective, then the lower portion of the tank will not be heated and the supply will be greatly reduced.
Check for power at the upper thermostat terminals where the power is sent to the lower thermostat and heating element. If there is no power then the upper thermostat should be replaced. If there is power then check for power at the lower heating element. If there is no power at the lower heating element then replace the lower thermostat.
If there is power to the lower heating element then it should be getting hot. If it is not, replace it. Another possibility is a broken dip tube. Check for a broken dip tube and replace if necessary.

Hope this helps out

Hi,
No, the top thermostat will always heat first and then it should dwitch the power to the bottom one after the top of the tank heats...this is to get you hot water faster...
The top thermostat is bad and is not shutting off or switching....
Replace the top thermostat/reset combination and you''l be good!!

Check out this tip..

How to replace the Thermostat and Element for Electric Hot Water Heater

heatman101

Check the elements, if you have access to a meter to check them. If they are getting power to elements and you have no hot water.
The elements are not working correctly. I had some elements check out ok till the thermostat's turned on and the elements didn't heat.
Sounds like the elements are bad.

First things first, you are not supposed to have power to both elements at the same time. The top element comes on and heats the top of the tank, then the top goes off and the bottom comes on. Now, check power on the top element, put your meter probes on both screws on the element, you must have 220 to 240 volts between these two screws. If the voltage is good then you have a bad element, if the voltage is not there, then you need to check the voltage at the top 2 screws on the upper thermostat, if it is okay there, maybe the hi limit has tripped, push the reset button on the top thermostat, if it is tripped it will click and start heating right away. If the hi limit is not tripped then you will need to replace the upper thermostat.

Hi,
Go to this link and page down, it gives you the wiring diagram for a dual element hot water heater.

http://www.plumbingsupply.com/element-installation-instructions.html

I hope that this will help you to solve your problem!

Thanks for using Fixya!!

Heatman101

I have the smae problem but my element on top works fine it is the element on the bottem that does not go on so what is it that i have to change the element or the thermostat. on the bottom or the one on top. I have voltage on the top but none on the bottom element and are they suppose to go on the same time.