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How to replace electric water heater elements

My last day off did not start out quite as planned, as my long to do list had to be put on hold. I turned on the shower so the hot water, which comes from the water heater in the basement, on the other side of the house would work its way to me. It usually takes 30 seconds to warm up but this morning the hot water did not show up. Being that this water heater is 17 years old but still looks brand new, I could only believe that it was time for some new elements.

To be sure I went down to the water heater and hit the red reset button that is located on the thermostat, just to make sure that a storm from the night before or a power surge was not the culprit for its not working. I also checked the breaker box to make sure the circuit breaker was not tripped.

Once it was established that I was in fact going to need to replace the elements, I started taking the necessary steps to replace them.

  1. Turn off the circuit breaker to the Water Heater (usually a 30 amp)
  2. Turn off the water going to the water heater
  3. Remove plastic terminal protector
  4. Turn on the hot side of a faucet in the house (to help it drain the tank)
  5. Connect a long water hose to the drain on the bottom of the tank securely
  6. Gravity feeds the water out so keep it below the tank and run outside
  7. Open the drain and water will drain out (my 50 gal took about 30 minutes)

Once the water was no longer running out of the hose, I knew that the tank was empty. Next, I found the sticker that tells me which watt heating elements my tank has. Most tanks have an upper and lower element. You might as well replace both if they are older. This tank shows 4500 watt upper and lower elements.

The elements are found behind the upper and lower access panels on the tank. Once they are removed with a screwdriver there will be insulation inside that can simply be pulled out.

While you are at Home Depot picking up your elements, you will need to pick up a element removal socket which is found right there with the elements. There will be two wires connected to each element. Remove them with a screwdriver and get the socket and a long screwdriver to twist off the elements. Make sure the old gasket or rubber washer comes off and make sure the gasket area is clean for the new element to seat and seal cleanly.

Once the elements are replaced and the wires are reconnected, it is time to refill the water heater. Close the drain, remove water hose and with the hot knobs of the faucets in the house slightly on, you will need to turn the water to the water heater back on. DO NOT TURN THE POWER TO THE WATER HEATER BACK ON. The water heater must be filled back up and the faucets need to have water coming from them to insure that the tank is full and the air is out of the lines. Once this happens then you are good to turn the breaker back on. Turn off the faucets that you opened.

Make sure there are no leaks and put plastic terminal protector back on. Put insulation back in and screw access panel back on.

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Posted 2016-12-04T16:44:36+0000  by Ingar_HD_ATL Ingar_HD_ATL
Hey Ingar.  Great post!

Somewhere around 90% of the time, when an electric water heater quits heating like it used to, indeed one or both of the elements are bad.  That is why once you checked the breaker and then reset the heater the likely culprit was a bad element, (or both).

For the other 10%, diagnosing what's wrong involves tracing live 240 volt power starting at the breaker and moving through various connections on the heater.  Professionals can do this safely and quickly, though I don't recommend this process for DIY homeowners.  There is something a homeowner can do before draining the tank and removing the elements though.

First, after making SURE that the power to the heater is off, remove the covers as Ingar noted, and look for any trace of water or corrosion.  If you see water, either behind those covers or on the floor, it's time for a new heater.  Corrosion on terminals or lime streaks also means that it's time to buy new.  That water is coming from somewhere and will only get worse over time.

Next is a simple way to test the heating elements before draining the tank and replacing them.  While I think that every homeowner should have an inexpensive non-contact voltage tester to keep from working on live power, there is another simple tool that I find invaluable.  A multi-meter is an affordable tool to measure resistance which can tell you if some parts are good or not.


Since you know the design wattage each element is supposed to use you can measure their resistance and determine if they are good or not.  This works not only for water heater elements, but also electric stove, oven and dryer elements as well.  A 4500 watt element running 240 volts would have a target resistance of 12.8 ohms.  For 3500 watts it would be 16.5 ohms.  The formula is simply voltage squared divided by watts.  The exact value is not critical though.  What you want to do is touch the test probes to the 2 terminals.  Remember that the power MUST be OFF!  If you get a resistance reading of between 10 and 20 ohms, the element is good.  Much over 20 and it's on its way out.  Also check the resistance of each terminal to the ground nut.  It should be infinite.  If not then you have a short and the element is bad.

Thermostats for the upper and lower elements are also available and fairly simple to replace.  They would be the likely culprits if you test the elements and they show good. 

Just my 2¢



Posted 2016-12-07T15:11:22+0000  by Chris_HD_CHI
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