How To Replace A Water Heater Gas Valve



Ah, yes! It’s almost time for the holidays. As Christmas and New Year’s get closer, family members will pour into your home. The weather is getting colder and colder each day, and today is the first day of winter! Is your water heater pulling its weight so far? A little more than half of all the water heaters in the U.S. are gas powered, and there are common issues to watch out for. If you’ve noticed the pilot on your heater is lit, the water is cold, and the burner isn’t working, the gas valve is bad. Let’s dive in and talk about how to replace a water heater gas valve.


What Is The Gas Valve?


The gas valve controls the amount of gas that flows into the heater. The valve enables the pilot to ignite, and the pilot light heats the thermocouple. What’s a thermocouple? A thermocouple is a safety device that shuts off the gas supply to the heater if the pilot isn’t lit. The thermocouple prevents explosions and fire in your unit and home. So, it makes sense that you would want the valve to be in working order to prevent disaster. 


How To Replace A Gas Valve On A Water Heater


Before replacing the gas control valve, ensure this is the issue with the heater. There’s a good chance the issue could be a worn-out thermocouple. If you’ve already replaced that, it’s most likely the valve. 

You’ll want to grab a new gas valve once you’ve determined it’s the issue. The best way to do this efficiently is to bring the old valve with you to make sure you get the right model. 


Step 1: Turn Off The Gas


The most important step for the entire process is to turn off the gas. Without cutting off the gas, you risk fire, explosion, serious injury to yourself or others, and death. Find the thermostat on your current valve and turn it to the off position. Next, turn the gas supply lever on the pipe so that it’s perpendicular. When the lever is perpendicular to the pipe, it is off. When it comes to gas, your nose is your best tool. If you smell gas at any point, call the gas company immediately and get away from the heater. Gas smells like eggs or sulfur. 


Step 2: Cut Off The Water

Turn off the cold water supply to the water heater. Turn this valve off by flipping the lever down 90º. 


Step 3: Drain The Water Heater

Now, you need to get all the water out of the heater tank. To do this, follow these steps: 

  1. open a hot water faucet
  2. find the drain valve and attach a garden hose to it at the bottom of the tank
  3. open the valve and wait for all of the water to drain out


Step 4: Take Off The Bad Control Valve

To get started with taking off the gas control valve, make sure the pilot and thermal fuse wires are disconnected. Then, screw a threaded pipe into the valve’s inlet and use it to unscrew the valve without damaging it. Do not use any kind of wrench so you don’t cause any unnecessary damage. 


Step 5: Install The New Valve

Before you install the new valve, make sure the connections will be sealed by wrapping some plumber’s Teflon tape around the threads that go into the heater. This will avoid any unnecessary leaks. 

Finally, use the threaded pipe you used to remove the old valve, screw in the new valve until snug and parallel with the water heater. Be careful not to overtighten. 


Call For Help


The truth is, working with gas is dangerous. If you don’t feel comfortable tackling a replacement project yourself, please give us a call. At Autry Plumbing, we’re your premier plumbing service in Western North Carolina.

We look forward to serving you soon!