How to Install or Replace a Tank Style Water Heater

Step 1

Pull Permits

Make sure you pull any required state or city permits for installing or replacing a water heater.

Step 2

Read the Labels on the Current Tank

It has helpful information for when you purchase a new unit, like energy specifications and size.

Step 3

Be Sure Your Venting Works

• Shut all doors and windows. 
• Turn on all exhaust fans and gas appliances.
• Turn up the tank temperature for a few minutes.
• Hold a just-extinguished match near the vent hood.
  • The hood should pull in the smoke. If the smoke blows back toward you, you have a venting issue and should call an expert for repairs.

Step 4

Check Your Water Pressure

Use a pressure gauge on your outdoor spigot to check your home’s water pressure. The ideal range is 50 to 60 psi.

• If the reading is higher than 80 psi, use the pressure-reducing valve installed after the main water shutoff to lower it.
• You should consider getting an inline pressure gauge and a thermal expansion tank. An expansion tank helps get rid of excess pressure in the lines.
  • You can use push-fit fittings to easily install an expansion tank.They easily slide under the pipe without the need for soldering.
  • The expansion tank pressure should match the main water pressure. You can depress the valve to lower it, or use a hand air pump to increase it.

Step 5

Remove the Old Water Heater

• Turn off the gas, and disconnect the gas pipe from the control valve with a wrench. 
• Detach the venting. 
• Open a faucet on the hot water side. Let the water run until it’s cool. 
• Turn off the cold water supply.
• Connect a garden hose to the drain valve.
• Empty the tank into a drain or buckets after you open the valve. 
  • To drain the tank faster, open a hot water faucet.
• After the tank has emptied, remove the discharge pipe from the temperature and pressure relief valve (T&P relief valve). 
• Disconnect your water supply pipes. 
  • If you must cut them, leave them as long as possible. 
• Remove the old tank.

Step 6

Put the New Unit in Place

Place the new water heater in a drain pan & route it to a drain or the exterior of your home to avoid flooding.

Step 7

Install the Discharge Pipe on the T&P Relief Valve

When pressure and temperature are too high, this valve opens. 

If you don’t have a floor drain, put a bucket underneath the discharge pipe. The pipe should be no more than 6 inches above the bucket. 

Step 8

Connect the Water Supply Lines

You can easily connect the water with a flexible hose kit.

Step 9

Connect the Gas Supply Line

Check that your kit also has a gas hose. 

• Put plumber’s tape on the threads of the heat trap nipples. Attach hoses.
  • To reduce corrosion between two different metals, some areas may need dielectric fittings. 
• Put plumber’s tape on the connector body threads.
• Securely connect the body threads to the hose. 
  • Hold the hose up to the pipe. There should be a little slack.
  • Mark the pipe, and then cut it. 
  • Deburr the pipe.  
  • Slide the compression nut onto the pipe. 
  • Place the pipe into the fitting. 
  • Tighten the nut.

Step 10

Check For Leaks & Empty Air From the Tank

• Open the hot water side of the nearest faucet, after removing the aerator.
• Turn on the cold water supply at the water heater. Check for leaks around the water heater.
• If everything looks good, continue letting the tank fill. You can tell the tank is full when water runs from the faucet.
• Allow the water to run from the faucet for about 3 minutes to empty air from the tank.

Step 11

Attach the Venting

Attach the existing venting to the new exhaust hood. If you do not have existing venting, you’ll need to vent your gas water heater through your roof. We recommend calling a licensed plumber for proper venting.

Step 12

Connect the Gas Line

• Make sure the tank’s control knob is turned off.
• Wrap gas plumber’s tape around the threads of the fittings. 
• Insert a flare nut into the control valve. 
• Screw the other flare nut into the gas line. 
• Connect the hose. 

Step 13

Check for Gas Leaks

Turn on the gas supply. Check for leaks with leak detection solution. 

• If you have a leak, the solution will bubble.
• If needed, tighten the connections.

Step 14

Light the Pilot on the Water Heater

To light the water heater pilot, turn the control knob to pilot and push the igniter button. When it’s lit, the light will blink.

Step 15

Adjust the Temperature Setting

The recommended temperature setting is 120 degrees Fahrenheit, but you may want it hotter or cooler depending on your personal preference. Test the temperature of the water at a faucet and then adjust the temperature on the thermostat.

Step 16

Perform the Vent Test Again

Repeat the same vent test steps as above.  If there’s a problem, call an expert to assess the issue.

Step 17

Check the Discharge Pipe

After waiting a few hours, examine the discharge pipe. 

• If the pipe drips, that usually indicates that the pressure is too high. Adjust the pressure to under 80 psi. 

Step 18

Check Your Faucets

Sometimes faucets have reduced flow after replacing a water heater due to sediment trapped in the line. If this happens, just remove your aerator and flush out the sediment before replacing it.

Step 1

Pull Permits

Make sure you pull any required state or city permits for installing or replacing a water heater.

Step 2

Read the Label on the Current Tank

It has helpful information for when you purchase a new unit, like energy specifications and size.

Step 3

Check Your Water Pressure

Use a pressure gauge on your outdoor spigot to check your home’s water pressure. The ideal range is 50 to 60 psi.

• If the reading is higher than 80 psi, use the pressure-reducing valve installed after the main water shutoff to lower it.
• You should consider getting an inline pressure gauge and a thermal expansion tank. An expansion tank helps get rid of excess pressure in the lines.
  • You can use push-fit fittings to easily install an expansion tank.They easily slide under the pipe without the need for soldering.
  • The expansion tank pressure should match the main water pressure. You can depress the valve to lower it, or use a hand air pump to increase it.

Step 4

Remove the Old Water Heater

• Go to the circuit breaker, and turn off the electricity. Use a voltage detector to confirm that the power is off.
• With tape, mark how the wires are connected and then disconnect them.
• Turn on the hot water for a  faucet. Run the water until it’s cool. 
• Turn off the cold water supply. Connect a garden hose to the drain valve. 
• Empty the tank into a drain or buckets after opening the drain valve. Turning on  a hot water faucet can help drain the tank faster.
• After the tank has emptied, remove the discharge pipe from the temperature and pressure relief valve (T&P relief valve).
• Disconnect the water supply pipes. If you need to cut them, leave them as long as possible. 
• Remove the old tank.

Step 5

Put the New Unit in Place

Place the new water heater in a drain pan & route it to a drain or the exterior of your home to avoid flooding.

Step 6

Install the Discharge Pipe on the T&P Relief Valve

When pressure and temperature are too high, this valve opens. 

If you don’t have a floor drain, put a bucket underneath the discharge pipe. The pipe should be no more than 6 inches above the bucket. 

Step 7

Connect the Water Supply Lines

Step 8

Check For Leaks & Empty Air From the Tank

• Open the hot water side of the nearest faucet, after removing the aerator.
• Turn on the cold water supply at the water heater. Check for leaks around the water heater.
• If everything looks good, continue letting the tank fill. You can tell the tank is full when water runs from the faucet.
• Allow the water to run from the faucet for about 3 minutes to empty air from the tank.

Step 9

Connect the Wiring

Wait until the tank is completely full before connecting the wire. This helps avoid dry firing, which damages heating elements.

• Take off the junction box cover.
• Attach the ground wire to the green ground screw.
• Twist the wires together with wire connectors. Use the previous connections to guide you.
• Put the cover back on.
• Turn on the power. If you don’t have power, turn off the circuit breaker and check your connections.

Step 10

Adjust the Temperature Setting

The recommended temperature setting is 120 degrees Fahrenheit, but you may want it hotter or cooler depending on your personal preference. Test the temperature of the water at a faucet and then adjust the temperature on the thermostat. It might take several hours to initially heat the water.

Step 11

Check the Discharge Pipe

After waiting a few hours, examine the discharge pipe.

• If the pipe drips, that usually indicates that the pressure is too high. Adjust the pressure to under 80 psi.

Step 12

Check Your Faucets