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Electric Water Heater Installation: Step-by-Step Guide


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Installing an electric water heater isn't as difficult as you might think, especially if you're a DIY kind of person. But before tackling the job, you should consider that you will need to do some basic plumbing as well as electrical work. If these kinds of tasks make you nervous, there are plenty of reputable company's you can call to install your new water heater. But, if you're up to the challenge, you can save yourself some money and do it yourself.

Electric water heaters tend to only last 8 to 10 years before they need to be replaced. Just because your water heater is leaking, doesn't mean that it has reached the end of its life. Before buying a new water heater, you should Troubleshoot the leak if you haven't already. Many times a leak can be repaired. However, if you find the source of the leak is from the tank itself, your only option is to replace the water heater.

Electric Current

Preparing to Install an Electric Water Heater

If you've determined that you need to purchase a new water heater you may want to check out our buyers guide to help you find the best one to meet your needs. And, if you decide to install the water heater yourself, you'll need to remove your old water heater and dispose of it properly.

Top of an electric water heater

Electric Water Heater Installation

Installing an electric water heater is much easier than installing a gas heater, but it's still a bit of a challenge. If you're uncomfortable working with electricity and plumbing we highly recommend hiring a professional to do the installation, in addition, they'll typically dispose of your old water heater for you.

Step-by-step instructions on how to install your electric water heater:

Disconnect the Electricity

Step 1

Turn OFF the electricity to your water heater at the circuit breaker panel. 

Check the water heater wiring with a voltage tester to make sure that the unit is off. This is not covered in the video below, but you should always check that the water heater is not receiving any electricity after shutting it off at the circuit breaker before working on it.

Drain the Tank

Step 2

Open a hot water faucet and allow the water to run until it is cold. This step is not covered in the video, however, it will ensure that you'll be able to safely drain the tank without being scalded.

Shut off the cold water supply to the water heater (located at the top of the unit). 

Connect a hose to the water heater's drain valve. Open the valve and drain the tank outside (or to a floor drain, or even into buckets).

If you closed the hot water faucet in Step 1, you should open it again. You can also open the T&P valve. This will help the water drain faster by allowing air into the tank.

Draining a water heater

Disconnect the Electrical

Step 3

Disconnect the electrical wires on the top of the water heater. Be sure that you turned off the circuit breaker at the breaker box first. Then, before starting, check the wires with a voltage tester.

Cap the wires off and label (or take a picture) of them to avoid any future confusion when you are hooking your new water heater up.

Disconnect the electrical

Disconnect the Plumbing

Step 4

Disconnect the hot and cold water supply lines. If your water heater was plumbed with copper piping, you may need to cut the pipes. If you need to cut the pipes, use a tubing (pipe) cutter and leave as much of the pipe as possible.

If the T&P discharge pipe is in good repair you can remove it from the T&P valve and reuse it on your new water heater.

Disconnect the Plumbing

Remove the Old Water Heater

Step 5

Once the tank is empty, remove the old water heater with a dolly.

Move the new tank into place. We recommend setting the new tank into a drain pan. Learn why

Check that your electrical supply will adequately reach the tank. Double check that you can access the panels and the drain valve for maintenance.

Prepare the Plumbing Lines

Step 6

If your old water heater used copper piping, and it was necessary to cut the pipes, you'll need to prepare the pipes using sandpaper cloth. Rub the sandpaper cloth on the ends of the pipes until they shine brightly.

Preparing the pipes for your new water heater

Connect the Electrical Wiring

Step 7

Remove the junction box cover to access the electrical wires.

Attach the ground wire to the green ground screw. Connect the other wires together by twisting them with wire connectors. Use the previous wire connections as a guide and connect the wires in the same way you removed them. Follow your label tags, or the picture you took, from Step 3. Then replace the junction box cover.

Attaching the electrical to an electric water heater

Attach the Supply Lines & Turn On the Water

Step 8

Connect the hot and cold water supply lines. Be sure to connect the cold water pipe to the cold water inlet on the water heater (it's easy to make the mistake of connecting the cold to the hot). 

If your old water heater used copper piping, you may choose to plumb it with copper piping again. However, we highly recommend using flexible hoses to make the connections. Not only is it easier, but it's a recommended safety feature for earthquakes. Your plumbing will vary depending on your orignial configuration and your preference.

Attach the flexible hoses to the nipples on the water heater. In most cases, you'll need to line the threads with plumbers tape. We recommend using dielectric connectors to attach the flexible hoses to the hot and cold water pipes. These fittings will help reduce the corrosion between the two different metals.

Installing the supply lines to an electric water heater

Check the flexible hose connections for leaks by turning on the hot water tap at the nearest faucet. Then turn on the cold water supply to your water heater. This step is not covered in the video, but we recommend double-checking your plumbing before moving forward. If there are no leaks, continue to fill your water heater tank with water.

Once the tank is full, water will begin to flow out of the hot water tap.

Attach the T&P Discharge Pipe

Step 9

Install the discharge pipe to the T&P valve. The end of the pipe needs to be within 6 inches of the floor.

  • Use a 3/4" male copper fitting.
  • Paint pipe dope onto the outside of the fitting and the inside of the valve fitting.
  • Attach the fitting to the T&P valve fitting and tighten.
  • Clean the fitting the end of the pipe.
  • Paint soldering flux on the inside of the male fitting and the outside of the pipe.
  • Attach the pipe to the fitting.
  • Use solder and a torch to connect the pipe.
Electric Water Heater T&P Pipe Installation

Turn On the Power & Bleed the Hot Water Lines

Step 10

After your water heater tank has filled with water, turn on the circuit breaker at the main power box. CAUTION: Turning on the power before the tank has completely filled can cause the electric elements to dry fire if they are not fully submerged. This can ruin your electric heating elements.

If your water heater isn't getting power, be sure to turn off the circuit breaker BEFORE checking the electrical connections on the water heater.

Bleed Hot Water Lines

Step 11

To eliminate the air in the tank and plumbing, allow the hot water tap to run for a few minutes until it stops "sputtering". 

It may take a few hours before the water within the tank to become fully heated. 

The recommended temperature setting is 120° Fahrenheit.

Wait a couple of hours and check the T&P discharge pipe. If the pipe is dripping, the pressure may be too high.

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