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How to Install a Gas Hot Water Heater

Charlie S Sep 29, 2018
A gas hot water heater is more efficient and cost-effective than an electric water heater. Let's learn the procedure if you wish to install it by yourself.
The basic components of a gas water heater are cold water inlet, tank insulation, drain valve, burner control, gas burner, overflow pipe, water line, gas supply line, and hot water outlet. The Next section will give you steps on how you can install it yourself.

Materials Required

One should have knowledge of plumbing to install a water heater. Here is a list of all the tools and materials you will need for the installation:
  • Water heater
  • Pipe fittings
  • Soldering torch
  • Flex connectors
  • Screwdrivers
  • Pipe wrenches
  • 0.5" flare adapter
  • Hand cleaner
  • Pipe cutter
  • Gate valve
  • 240 Volt neon test light
  • Natural gas outlet


Ensure that the center-to-center dimensions between the hot and cold pipes on top of the new water heater are the same as the original one. You should have a gas union in the gas line.
Disconnect the utilities of the current gas water heater. Gas supply to the water heater should be turned off. This can be confirmed by checking if the pilot light is out. Drain the tank before installing the new water heater.


  • Carry the gas water heater to the place where it is to be installed using a cart, dolly, or by manually lifting it. You will need someone's assistance for this.
  • Affix the gas water heater in such a way that the gas vent pipe is visible clearly.
  • Now, install the heater's new draft hood. The legs of the heater should fit into the holes present on top of it.
  • The old vent pipe elbows may be corroded because of excessive use. It is advisable to use new vent pipes in place of them. Connect the vent pipe with metal screws.
  • After completing this, make the hot and cold water connections using the flex connectors.
  • Next, attach the cold water gate valve to the heater using a vertical pipe. The pipe will protect the valve from coming in contact with the sediment.
  • The hot and cold water lines should have a union if you are using a threaded pipe. Flex connectors can also be used instead of unions.
  • If the tappings of your gas water heater are male, use a PTFE tape.
  • Sweat soldering should be done before installing the flex connectors. This will help prevent damage to the connector.
  • There are transition unions between plastic piping and metal heater threads.
  • You can use CPVC tubing which is known for its rigidity or a PB pipe which uses mechanical couplings to join the joints.
  • After the plumbing work is over, fill the storage tank with cold water by opening the cold water inlet valve.
  • Close the valve after the storage tank is filled completely.
  • Ensure that there is no leakage of water from the storage tank.
  • Note that the gas line must have a shut-off valve. The gas line is installed with the threaded pipe using a union. Do not use old unions because they may be faulty due to prior usage.
  • The gas valve of the gas heater has an inlet opening. If you are using a flex connector, insert a flare adapter into the inlet opening.
  • Use an open-end wrench to tighten the gas flex connector collar which has been connected to the flare adapter.
  • You can turn on the knob now and hear the ignition sound of the burner. Turn off the knob immediately after you finish your work.
  • Check for gas leakage; it can result in serious accidents if left unattended.
People living in earthquake zones should use a protection made of sheet metal straps for the gas water heater to protect it from getting damaged. Refer to the user's manual if you have some technical problems.
Installing gas water heaters is very easy. It just requires concentration and patience. You can do the job yourself and save a lot of money charged by plumbing professionals.