Tip & How To about Water Heaters
How to replace the Thermostat and Element for Electric Hot Water Heater
Posted by 
D. Floyd Kolb on Thursday, April 29, 2010
If you are having a problem with your electric hot water heater then you may also wonder if you can replace the failed part. The short answer to this is yes! The replacement is easy enough that most any handy person can easily perform this task.
First off make sure that you remove all power to your electric hot water heater. Then remove the access covers that cover the thermostats and the heating elements. After performing the required diagnostic tests to find the fail part you can then concentrate on the part removal and replacement. Check the tips at the bottom of this one to see how to trouble shoot your hot water heater.
To replace the heating element you may have one of two styles of element. One style has a four bolt flange that holds the element in and the other has threads that hold it in.
Before removing an element make sure that you shut off the water and drain the tank to a level below that of the element that you need to replace. This will keep you from making a mess and possibly hurting your self with the hot water.
For the four bolt flange type element, you simply remove the two wires from the element and then turn out the bolts from the flange. Once the flange is off the element will just pull back and out of the hole.
Replace with a new element and gasket. Make sure that the new gasket gets seated in the hole to seal the element when you tighten down the bolts on the flange again. The bolts do not need to be super tight. Just snug them up good and then fill the hot water heater with water to check for leaks and then tighten more if necessary.
For the screw in elements, a removal tool is a good idea.
A large socket looks like it would work, but because of the thinness of the hex part of the element and the bevel on most large sockets, it is very difficult to get them to grip the element securely. Most hardware stores or home centers sell a very inexpensive removal tool that works very effectively. It is well worth the effort to get the proper tool to do the job. To remove the screw in element you need to turn the element to the left or counter clockwise. Then make sure that you do not cross thread the new element as you turn in clockwise or to the right and tighten it in. Once again, make sure the gasket is seated correctly and do not over tighten. Re-hook the wires after leak checking the tank and replace the cover before energizing the electric hot water heater.
To replace either the top or bottom thermostat, you also need to de-energize the hot water heater and remove the cover. When removing a thermostat it is a very good idea to mark the wires and the position where they were on the old thermostat. This makes the re-installation of the new thermostat easier. The old thermostat is held tightly too the tank so that it gets a good reading on the tank temperature. Be careful not to bend the bracket that holds the thermostat when you remove the old one. If you do not have the new thermostat making good contact with the tank it will not operate correctly and give you too hot of water. After switching the old thermostat with the new one, replace all of the wires to their correct position, replace the plastic, and the cover before energizing the hot water heater. Both the top and bottom thermostats are similar in their replacement, but the top thermostat also incorporates a safety reset control and switches power to the bottom element when the top of the tank is hot enough, so there a re a few more wires to that thermostat. This also keeps the two thermostats from being interchangeable. You cannot install a bottom thermostat or the top or a top one on the bottom.
This whole process is not as complicated as it may seem and you can do it!
http://www.fixya.com/support/r4654730-electric_water_heater_not_working
http://www.fixya.com/support/r4422595-electric_water_heater_wiring_diagram
http://www.fixya.com/support/r4656190-electric_hot_water_heater_temperature
http://www.fixya.com/support/r4041115-clean_hot_water_heater
http://www.fixya.com/support/r3689051-home_water_heaters_hot_water_heater
First off make sure that you remove all power to your electric hot water heater. Then remove the access covers that cover the thermostats and the heating elements. After performing the required diagnostic tests to find the fail part you can then concentrate on the part removal and replacement. Check the tips at the bottom of this one to see how to trouble shoot your hot water heater.
To replace the heating element you may have one of two styles of element. One style has a four bolt flange that holds the element in and the other has threads that hold it in.
Before removing an element make sure that you shut off the water and drain the tank to a level below that of the element that you need to replace. This will keep you from making a mess and possibly hurting your self with the hot water.
For the four bolt flange type element, you simply remove the two wires from the element and then turn out the bolts from the flange. Once the flange is off the element will just pull back and out of the hole.
Replace with a new element and gasket. Make sure that the new gasket gets seated in the hole to seal the element when you tighten down the bolts on the flange again. The bolts do not need to be super tight. Just snug them up good and then fill the hot water heater with water to check for leaks and then tighten more if necessary.
For the screw in elements, a removal tool is a good idea.
A large socket looks like it would work, but because of the thinness of the hex part of the element and the bevel on most large sockets, it is very difficult to get them to grip the element securely. Most hardware stores or home centers sell a very inexpensive removal tool that works very effectively. It is well worth the effort to get the proper tool to do the job. To remove the screw in element you need to turn the element to the left or counter clockwise. Then make sure that you do not cross thread the new element as you turn in clockwise or to the right and tighten it in. Once again, make sure the gasket is seated correctly and do not over tighten. Re-hook the wires after leak checking the tank and replace the cover before energizing the electric hot water heater.
To replace either the top or bottom thermostat, you also need to de-energize the hot water heater and remove the cover. When removing a thermostat it is a very good idea to mark the wires and the position where they were on the old thermostat. This makes the re-installation of the new thermostat easier. The old thermostat is held tightly too the tank so that it gets a good reading on the tank temperature. Be careful not to bend the bracket that holds the thermostat when you remove the old one. If you do not have the new thermostat making good contact with the tank it will not operate correctly and give you too hot of water. After switching the old thermostat with the new one, replace all of the wires to their correct position, replace the plastic, and the cover before energizing the hot water heater. Both the top and bottom thermostats are similar in their replacement, but the top thermostat also incorporates a safety reset control and switches power to the bottom element when the top of the tank is hot enough, so there a re a few more wires to that thermostat. This also keeps the two thermostats from being interchangeable. You cannot install a bottom thermostat or the top or a top one on the bottom.
This whole process is not as complicated as it may seem and you can do it!
http://www.fixya.com/support/r4654730-electric_water_heater_not_working
http://www.fixya.com/support/r4422595-electric_water_heater_wiring_diagram
http://www.fixya.com/support/r4656190-electric_hot_water_heater_temperature
http://www.fixya.com/support/r4041115-clean_hot_water_heater
http://www.fixya.com/support/r3689051-home_water_heaters_hot_water_heater
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