How to Install a Gas Water Heater
Time Required: Under 2 hours
Gas water heaters require a gas supply, a cold water supply and a flue connection to carry away harmful gases. Learn more about the process of installing one of these units in this guide.
Safety: The Home Depot highly recommends that you hire a professional to install your water heater. Our services are available for same-day installation when you call before noon in most areas. Schedule an appointment today.
- Disconnect the gas line using two pipe wrenches -- disconnect the gas line at the union fitting if the pipe is galvanized, or at the flare fitting if the gas supply line is copper.
- Using two adjustable wrenches or pipe wrenches, disconnect the water lines above the tank. If the piping has been soldered into place, use a hacksaw or tubing cutter to cut the pipe. Make sure the cuts are straight.
- Remove the screws connecting the vent to the water heater using a screwdriver or nut driver.
- Remove the old water heater – you may require help for this because older water heaters fill with sediment and are heavier than new ones.
- Install the water heater in an area with at least 6 inches of clearance on all sides for ventilation. Allow unobstructed access to the burner and controls.
- Place a carpenter’s level on the side of the water heater and level it with plastic shims if necessary.
- Reconnect the flue hat to the gas exhaust vent.
- Wrap the water heater heat trap fitting pipe threads using Teflon tape. These fittings are directional and must be installed properly -- both have arrows showing the correct direction for installation.
- Attach the blue-coded fitting to the cold water inlet with the arrow facing into the water heater.
- Attach the red fitting to the hot water outlet with the arrow pointing away from the water heater.
- Tighten using a pipe wrench or adjustable pliers.
- Before connecting the gas line, clean all threads with a wire brush and rag.
- Apply piping compound to the threads of the black pipes as you connect them.
- Assemble and tighten each fitting with two pipe wrenches.
- Install the union fitting last because it connects the new line to the existing line. When finished, open the gas supply valve and turn the water on.
- Turn on water at the tank, then turn on one or more hot water faucets to bleed air out of the system.
- Fill a sponge with a mixture of liquid dishwashing soap and water, and apply it to the new fitting. Check for bubbles.
- Test all connections. If there's a leak, bubbles will form on the surface and you'll have to refit the joint.
- Remove the burner access panel.
- Turn the knob on top of the control box to the pilot position.
- Hold a lit fireplace match or barbecue lighter to the pilot access opening.
- Press and hold down the reset button on the control box for 60 seconds after the pilot ignites.
- Turn the knob on top of the control box to the On position -- you should hear the burner ignite.
- If it doesn't, remove the access panel and relight the pilot.
- Replace the burner access panel and set the control at a temperature between 118 and 123 degree