How to Install a Gas Hot Water Heater

One of the best assets you can have for your home is a natural gas hot water heater. It’s often cheaper to operate than an electrical model, delivers on-demand supplies at a high rate, and quickly recharges to offer more for those long showers and baths.

Knowing how to install a gas hot water heater is a little trickier than the skills needed for an electrical model. If you don’t know how to work with natural gas, this job should be given to a professional to complete instead of being considered a DIY opportunity.

What Are Your Installation Considerations? 

If you replace a water heater with gas piping and combustion venting, the first step is to check the labels on the previous tank for energy and size specifications. The tanks built in 2015 or later have more insulation, causing the units to get physically bigger while having the same capacity.

You’ll need to measure the area where the old water heater sits. If it was installed before 2015, compare the specifications from the latest model to see if there is enough space.

A permit might be required to install a gas hot water heater at home. You’ll need to confirm the work with your local utilities, city government, or other officials. An inspection might be required within a specific time after the installation is completed.

Steps to Follow When Installing a Gas Hot Water Heater

If you’re ready to install a natural gas hot water heater, these steps can help the job get done quickly and efficiently. Please do not attempt to work on the gas pipes unless you’ve been appropriately trained.

1. Drain the tank of your water heater.

You’ll need to turn off the water supply to the unit. The control valve must also be in the off position. That’s when you can turn off the gas supply.

Turn on the nearest faucet and allow the hot water to drain until it becomes cold. Then, attach a garden hose to the drain valve, and empty the remaining water into the drain, buckets, or another safe spot outside.

2. Disconnect the lines.

After confirming the gas supply is shut off to the hot water heater, you’ll need to connect the gas line with the appropriate tools. If it has a black iron pipe, this step should happen at the union fitting.

Then disconnect the water lines above the tank. If the pipe has a soldered connection, you’ll need to use a tube cutter to complete this step.

Once those chores are finished, you need to remove any gas piping still attached to the gas valve. If it is made from black iron, keep the sediment trap and tank tee intact.

3. Detach the exhaust.

Your natural gas water heater has an exhaust that extends outside the home. You must remove the screws that connect this pipe to the water heater. Once it is disconnected, try to inspect the components for damage or rust, replacing any of the flues that seems in poor condition.

You can now dispose of your old water heater appropriately.

4. Install the new gas water heater.

Align the new water heater so that you have fast access to its controls and the burner. Please remember to follow the manufacturer’s guidelines and local code requirements, including the minimal clearances needed for combustible materials.

Use a level and shims to complete the installation as needed. Once it is ready, you can connect the flue hat to the exhaust vent. You must use a non-metallic plastic vent pipe to meet modern code requirements.

Once secured, you can connect the water line connections and heat trap fittings. This step might include measuring and cutting the lines to the appropriate length. When sweating the copper connections, try to dry-fit everything first to ensure everything works as expected.

It also helps to sweat the threaded fittings first. Let them cool before installing them onto the heat trap components. Next, apply flux, assemble, and solder using a propane torch. That’s when you can reconnect the water line, attached the pressure relief valve, and prepare the unit for accepting water.

The Final Step Is to Connect the Gas Supply

Before you connect the gas line, the threads should get cleaned with a wire brush and rag. Apply thread seal tape or pipe compound to the black pipe threads when connecting them. If you’re using an installation kit, follow the instructions provided.

Use two pipe wrenches to assemble and tighten the fittings. You’ll want to install the union fitting last since it connects the new line to the existing source. Use pipe joint compound rated for natural gas to secure the flare connection.

Test for leaks, light the pilot and turn on the water heater. That’s how you install a gas hot water heater.