Removing the Old Water Heater
Turn off the electricity at the circuit breaker. Use a circuit tester to make sure the power is off. Use tape to mark the wire connections and disconnect the wires.
With the water supply still on, turn a faucet on hot and let it run until the water is cool. Shut off the cold-water supply line and connect a garden hose to the drain valve on the bottom of the water heater.
Open the drain valve and empty the water heater into buckets or down a drain. Sometimes opening a hot-water faucet on a sink helps the water heater tank to empty faster.
When the tank is empty, remove the discharge pipe from the temperature and pressure (T&P) relief valve. Disconnect the water supply lines. If you must cut them, leave them as long as possible. Have someone help you remove the old tank with a hand truck.
Installing the New Water Heater
The following steps will explain how to install an electric water heater.
Place the new water heater in a drain pan. You can avoid possible flooding by routing a pipe from the drain pan to a drain.
If your water heater didn't come with a new T&P relief valve installed, simply twist in the new valve now. It may be in the box or you may need to buy your own. Don't reuse the old valve. The T&P valve automatically opens if the temperature or pressure becomes too high for the tank. The T&P valve most of the time came directly installed.
Position the discharge pipe from the T&P relief valve toward the floor or drain. If there's no drain underneath the pipe, put a bucket underneath to catch water dripping from the discharge pipe. Cut the pipe so it's no more than 6 inches above the bucket.
Use a flexible hose kit for water hookup. In Illinois is prohibited to use flexible hose. Use type "L" or "M" copper pipe. Apply plumbers tape to the threads of the heat trap nipples. Then attach the hoses.
Some areas require dielectric fittings to reduce corrosion between two different metals. Your area’s local codes and ordinances should detail the specifics of installation in your area.
Add plumbers tape to the connector body threads. Secure the fitting to the hose and then hold the hose up to the pipe. It should have a little slack. Mark and cut the pipe, removing any burrs.
Slide the compression nut and ring onto the pipe. Push the pipe into the fitting and tighten the nut.
Some areas require seismic straps to prevent earthquake damage. These straps brace the water tank against the wall to keep the unit from toppling over. If you’re not in an earthquake zone, skip ahead to the next step.
Seismic straps should be installed approximately 6 inches from the top of the water heater and 18 inches from the bottom. Locate the wall studs closest to the strap measurement and drill pilot holes.
Secure one end of the strap to the stud with a socket and ratchet. If blocks cover the studs, use a masonry bit to create a pilot hole. Wrap the strap around the water heater and adjust the size, securing the adjustable bracket on the opposite side. Pull the strap tight and repeat the process on the lower strap.
Remove the aerator from the nearest faucet and open the hot side. Slowly turn on the water supply and check connections around the water heater for leaks. If you're leak free, fill the tank. If you have leaks, shut off the water supply and gently tighten the connections. Repeat until the connections are secure.
When water runs from the faucet, the tank is full. Let the water run for three minutes to empty air and debris from the tank.
Remove the junction box cover. Attach the ground wire to the green ground screw. Use your masking tape connection notes as a guide. Twist the wires together with wire connectors.
Replace the junction box cover and turn the power on at the circuit. If your new water heater doesn't have power, turn the circuit off and check the connections.
Follow the manufacturer’s instructions to set the temperature to 120 degrees Fahrenheit. It may take several hours to initially heat the water.
After a few hours, check the discharge pipe that runs out of the T&P relief valve. A dripping pipe usually means the pressure is too high. Turn the pressure down below 80-PSI.
If a faucet stops running after installation, remove the aerator from the faucet in question and let the water run for a few minutes to clear loose sediment. Rinse and replace the aerator.
Preventing Scalds
Even with the temperature gauge set to 120 degrees, scalds are still a concern. Children, older people and those with sensitive skin are especially at risk. Consider installing thermostatic mixing valves to prevent injury.
Installed at the point-of-use faucet, fixture or appliance, a thermostatic mixing valve controls both the volume and temperature of water by attaching to both the hot- and cold-water supply. The settings may be adjusted inside the valve itself to provide optimum comfort.
