How do you turn on an electric water heater: A Comprehensive Guide

Do you buy a new electric water heater and you don’t know how do you turn on an electric water heater?

Here is what to do:

before thinking to turn on the water heater expansion tank you must be verified and follow these steps and instructions.

how do you turn on an electric water heater

How do you turn on an electric water heater in 6 steps:

Make sure before you start to turn on the water heater to follow these steps first:

Step1: Install shutoff and tempering valves

1.  If one is not already installed, install a manual shutoff valve in the cold water line that supplies the water heater. Install the shutoff valve near the water heater so that it is readily accessible.

 Only use valves that are compatible with potable water. Use only full-flow ball or gate valves. Other types of valves may cause excessive restriction of the water flow.

2. Install a thermostat Mixing Valve at each point of use (for example, kitchen sink, bathroom sink, bath, shower). Consult the valve manufacturer’s instructions or a qualified person.

3. For water heaters that are fed by a solar water heating system (or any other pre-heating system), always install a Thermostat  Mixing Valve or other temperature limiting device in the inlet water supply line to limit water supply inlet temperature to 120°F.

Solar water heating systems can supply water with temperatures exceeding 170°F and may result in water heater malfunction.

Step2: Connect the water supply

1. Determine the type of water pipes in your home. Most homes use copper water pipes, but some use CPVC or cross-linked polyethylene (PEX).

 Use fittings appropriate for the type of pipe in your home. Do not use iron or PVC pipe – they are not suitable for potable water.

2. Connect the cold water supply using 3/4 inch National Pipe Thread “NPT” to the cold water inlet nipple.

For ease of removing the water heater for service or replacement, connect the water pipes with a coupling called a union.

We recommend using a dielectric-type union (available at your local plumbing supplier ). Dielectric unions can help prevent corrosion caused by tiny electric currents common in copper water pipes and can help extend the life of the water heater

3. Connect the hot water supply using 3/4 inch NPT to the hot water outlet. Follow the same connection guidelines as for the cold water supply.

4. Install insulation (or heat tape) on the water pipes especially if the indoor installation area is subject to freezing temperatures. Insulating the hot water pipes can increase energy efficiency.

5. Double-check to make sure the hot and cold water pipes are connected to the correct hot and cold water fittings on the water heater.

6. If needed, install (or adjust) the home’s Pressure Reducing Valve to 50-60 psi and install a Thermal Expansion Tank.

Step3: Verify connections and fill the tank

To remove air from the tank and allow the tank to fill with water, follow these steps:

1. Remove the aerator at the nearest hot water faucet. This allows any debris in the tank or plumbing system to be washed out.

2. Turn the cold water supply back on.

3. Open a hot water faucet and allow the water to run until it flows with a full stream.

Let the water run full stream for three full minutes.

4. Close the hot water faucet and replace the aerator

5. Check inlet and outlet connections and water pipes for leaks. Dry all pipes so that any drips or leaks will be apparent.

Repair any leaks. Almost all leaks occur at connections and are not tank leaks.

Step4: electrical connections

1. Be sure the electrical power to the water heater is turned OFF at the circuit breaker panel (or remove the circuit’s fuses).

 2. Using a non-contact circuit tester, check the wiring to make certain the power is OFF.

3. Check the water heater’s data plate and ensure that the home’s voltage, wiring size (ampacity), circuit breaker range, and type are correct for this water heater

Refer to the wiring diagram located on the water heater for the correct electrical connection. Ensure that wire sizes.

4. Remove the cover on the electrical junction on the box on the top of the water heater.

5. Install wiring in an approved conduit (if required by local codes). approved strain relief to secure the electrical wiring to the water heater

6. Connect the ground wire to the green ground screw. Connect the home’s two power wires to the water heater’s two power wires. Use suitable wire nuts or other approved means to make the power connections.

7. Replace the junction on the box cover and secure it with the screws provided.


Do not turn electrical power on unless you are sure all of the air is out of the tank and the tank is full of water. If power is applied before the tank is full of water, the upper element will burn out (Dry Fire)

With the installation steps completed, you may adjust the water heater’s temperature setting if desired.

Step5: Adjusting the Temperature

1. Set the thermostat(s) to the desired temperature. The thermostat(s) on this water heater has been factory set to approximately 120°F to reduce the risk of scald injury. You may wish to set a higher temperature to provide hot water for automatic dishwashers or laundry machines, to provide more hot water capacity, and to reduce bacterial growth.

Higher tank temperatures (140° F) kill bacteria that cause a condition known as “smelly water” and can reduce the levels of bacteria that cause water-borne diseases

If you increase the water heater’s temperature setting, install Thermostat Mixing Valve(s) at each point of use to reduce the risk of scalding

To adjust the water heater’s thermostat:

  • Be sure the electrical power to the water heater is turned OFF at the circuit breaker panel (or remove the circuit’s fuses).
  • Remove the upper and lower access panels and fold away the insulation
  • Turn the water temperature dial clockwise to increase the temperature, or counterclockwise to decrease the temperature.

Adjust both thermostats to the same temperature setting. To avoid a shortage of usable hot water, do not adjust the upper thermostat to a temperature setting that is higher than the lower thermostat’s temperature setting.

  • Fold the insulation back in place and replace the access panels.

NOTE: Most models have two thermostats, but some models may only have one. If your water heater has only one thermostat, it is located behind the lower access panel

2. Turn the electric power back on.

3. Wait for the water to heat up. It may take several hours for a tank of cold water to heat up. If you have no hot water after two hours

4. Check water temperature at several points of use in your home (for example, bathtub faucet, shower, or lavatory sink) and adjust the Thermostat  Mixing Valves as needed. If you aren’t sure how to adjust the Thermostat  Mixing Valve settings or aren’t sure if you have Thermostat Mixing Valves

Step6: Operation

The water heater is now ready for normal operation. To keep your water heater working safely and efficiently and extend its life.

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To save energy, lower the temperature setting on the thermostat(s) if you plan to be gone for an extended time.

Follow the instructions in Step 5 for adjusting the thermostat to a lower temperature setting before you leave and to properly raise the temperature setting when you return.

After you read the steps above you might know the answer to how do you turn on an electric water heater? now you can easy turn your electric water heater without difficulty.


My Name is Elhoucine I am a passionate blogger, I have been searching and reading about the newly released gadgets, appliances, and products, and through this blog, I am trying to share some of the acquired experience to help you with everything related to home.