Replacing a Hot Water Heater Gas Valve


Replacing a hot water heater's gas valve is more straight-forward than you might think. However, before you replace your water heater gas valve, you should make sure that you know for sure that the gas control valve is broken in the first place. There's no sense replacing your gas valve if it's not broken. Unsure how to diagnose a broken water heater gas valve? No problem, we'll go over that too.

So, let's roll up our sleeves and get our hands dirty!

Is My Water Heater Gas Control Valve Broken?

First, it's good to first know whether or not the gas control valve is broken. Most modern-day water heaters will have a gas control valve with an LED indicator that'll help you to diagnose the problem quickly. Usually, it'll be a series of flashes (or flashes with a pause) that you'll need to count. You can cross-check the number of flashes with your manual and see if it matches the number of flashes for a faulty gas control valve.

For those who do not have a modern-day control valve, diagnosing a gas control valve issue is a bit more difficult. Here are some common issues which may involve the gas control valve:

  1. Pilot light won't light. This is very rarely a broken gas valve issue butworth mentioning because the fix is usually quick. In this case, the gas control valve might just bet set to an improper position and just needs to be adjusted. Check your manual for the correct position.
  2. Pilot light doesn't stay on. There are several issues which might lead to this condition. You can have a bad or faulty thermocouple, poor thermocouple connection, bad magnet in the gas valve, or you might just need to reset the thermal switch. If you checked everything else and the gas valve seems to bethe culrpit, you may need a new gas control valve.
  3. The pilot light comes on, but the burner won't stay lit. This problem may indicate that the temperature is set too low, and you need to turn it up. You may also have an insufficient gas supply (call gas company in this case). The gas valve may need to be calibrated. If everything else checks out, the gas control valve may be the culprit and need to be replaced.
  4. Not getting enough hot water. This may be simply that the temperature is set too low. Your hot water heater might be too small (not enough supply) or the demand for hot water is too high. You might even have an issue with your dip tube. If everything else checks out, the gas control valve may need to be recalibrated or replaced.

Although these are indications of needing to replace your gas valve, it is still a bit hard to actually diagnose the issue specifically unless you rule everything else out. In some case, you may need to call a technician. However, if you have a newer model gas valve, it should be easy to know if you need to replace your gas valve.

Steps to Replace a Water Heater Gas Control Valve

Replacing the gas valve isn't nearly as complicated as a repair technician would lead you to believe. In fact, there are several instructional videos online or on YouTube that may even have your exact model and show you how to replace it.

One of the best videos for replacing your water heater gas valve is the following:

How to Replace a Water Heater Gas Valve - Step by Step

This video is for an A.O. Smith water heater's gas valve but can be applied to replacing almost any similar gas control valve.

The steps outlined in the video are as follows:

  • Step 1: Unplug the power cord, shut off the gas to the water heater, and close the water intake valve. Open the drain valve to drain the water and turn on a faucet to empty the water heater. Be careful the water is hot. Close the drain valve.
  • Step 2: Separate the pipes that make up the gas pipe union. Remove all other pipes that are attached to the gas valve, including any connection pipes. This is most effectively done with two wrenches: a pipe wrench and a monkey wrench.
  • Step 3: Disconnect any wires which may be attached to the gas control valve. Remove the burner tube that's attached to the valve.
  • Step 4: Remove the gas control valve by turning it counterclockwise (in most cases). This may be done a little easier by screwing in a pipe into the empty pipe connection on the valve and using the pipe as leverage.
  • Step 5: Insert the new gas valve into the empty spot where the old valve was. Tighten the new gas control valve by tightening it clockwise (in most cases).
  • Step 6: Apply sealant to any connecting pipes that you need to reconnect. Reconnect all the tubes you removed from Step 2. Make sure all tubes are connected tightly.
  • Step 7: Remove access cover. Remove the vapor sensor. Remove the burner plate and the old burner from the water heater. Connect the new burner using any parts and screws that are included with your burner. Put the new burner and burner plate back into place. You will have to refer to your instructions in your manual here. Replace the vapor sensor.
  • Step 8: Connect any wires you removed from Step 3. Reconnect the burner tub and tighten the nut that holds it into place. Put back into place the access cover.
  • Step 9: Check your new setup for any leaks. Adjust the temperature gauge to the desired temperature. It is now good to go.

Any steps that may be confusing, please refer to the video above. It is best to watch the video and then use the steps as a reference. In fact, you'll be much better off if you watch the video one time first before attempting to do anything on your own. Also, be sure to follow any of the precautions in the video. Most importantly, be sure to shut off the gas, drain the hot water from the tank, and unplug the power cord before beginning.

Where To Find a Gas Control Valve Replacement

Some places where you can find a water heater gas valve replacement part are:

  1. Home Depot
  2. Lowes
  3. Direct from manufacturer
  4. Supply stores

You can also click here to search Amazon. Sometimes you might get lucky and find a control valve for a newer water heater.

If all else fails and you're looking for a gas valve for an old water heater, you might be able to find one at a junk yard. Also try calling local repair shops and see if they can source some parts for you.

B. Boyer

I love learning about water heaters, especially repairing and diagnosing water heater problems. I started this water heater website to help others fix, repair and diagnose water heater problems.