AO Smith Water Heater Gas Control Valve Troubleshooting

AO Smith Water Heater Gas Control Valve Troubleshooting [A Step-by-step Guide]

This is a step-by-step guide on AO Smith Water Heater Gas Control Valve Troubleshooting. Throughout this article, I will walk you through- 

  • How to tell if AO Smith Water Heater Gas Control valve is at fault? 
  • How to replace AO Smith Water Heater Gas Control Valve?
  • And a lot…

So, keep reading till the end.

Table of Contents

How To Tell If AO Smith Water Heater Gas Control Valve Is At Problems?

You can easily identify if the gas valve of your AO Smith Water Heater is at problem by observing the status light. If the status light on the gas control valve blinks 7 times, understand the gas valve gets bad. 

And a bad gas control valve means the unit doesn’t get the continuous gas flow for lighting the heater. As a result, you will get no hot water from your water heater. The only way you can get rid of this issue is to replace the gas control valve. 

The next chapter will walk you through the step-by-step guide to replace the gas valve on AO Smith Water Heater successfully. 

AO Smith Water Heater Gas Control Valve Troubleshooting: The Replacement

You must replace the gas control valve if it is at fault. To replace the water heater, ensure you have these pieces of equipment at your fingertips: 

  • A new gas control valve 
  • A 4” section of gas pipe 
  • A garden hose 
  • An adjustable wrench
  • A flathead screwdriver

Now, follow the below steps to replace the gas control valve: 

01. Turn the Gas Supply Off

Start with turning the gas control knob to the off position. Then, locate the manual gas shut-off valve, which you can find on the gas supply pipe and set it to the off position. As a result, no gas will flow to the unit when you replace the gas valve. 

02. Drain The Water Heater

Get a garden hose and connect it to the drain valve at the bottom of the water heater. Ensure you place the other end of the hose to the nearest floor drain. Then, turn off the cold water supply valve. 

Next, use a flat head screwdriver to open the drain valve and let the water drain. You can also open the hot water faucet to drain water faster. 

03. Disconnect Every Line From The Gas Control Valve

Now, what you need to do first is- detach the igniter wire from the gas control. Second, disconnect the red and white thermopile wires by using needle nose pliers. Third, use a 7/16” wrench to remove the pilot tube. And lastly, take out the manifold tube from the gas control using a 3/4” wrench. 

Don’t forget to disconnect the ground joint union in the gas piping. Besides, detach other piping from the gas control valve. 

04. Remove The Old Gas Control Valve

You are ready to remove the gas control valve from the unit. Just use a 4” section of gas pipe and thread it into the inlet. Then, turn the pipe counterclockwise to pull out the gas control valve

Precautions: Never use a pipe wrench or equipment like this to grip the body. It may damage the water tank and cause a leak. 

05. Install A New Gas Control Valve

Finally, it’s time to install the new gas control valve. First off, hand-tighten the gas control valve. Before installing it, you should use Teflon tape on the gas piping connections and fitting on the back of the gas control valve that screws into the tank. 

Now, tread the 4” section of pipe into the inlet and turn clockwise to tighten up the control valve. Stop avoiding yourself from over tightening the gas valve. 

Once you install a new gas valve, connect every line with the valve you detached before. After connecting everything, use a soap solution over the connections to check for a leak. Fill the water tank, and light the pilot following the instructions before using the unit. 


How to turn off AO smith gas water heater?

Just turn the gas control or thermostat knob counterclockwise to set it to the off position. The status light will stop flashing and stay on for a short time after the unit is turned off.

How do I reset my AO Smith Gas Water Heater?

Resetting your AO Smith Gas Water Heater is simple. What you need to do is- set the gas control knob to the off position and leave it for a few minutes to dissipate gas. Then, turn the knob to the pilot position. Now, press down the pilot button and keep depressing the igniter button. Keep doing this until the burner comes on. And it will reset your Ao Smith Gas Water Heater.

What happens if the pressure relief valve fails?

If the pressure relief valve fails, it may cause an explosion and bring damage to your property. So, it’s a must to call a professional if this valve gets bad and replace it if needed to avoid any damage.


It’s a must to replace the gas control valve if you notice the Status Light of your AO Smith Water Heater blinks 7 times. Just follow the 5 simple steps I mentioned above and replace the gas valve like a pro. It will help you bring the water heater back into its operating states. 

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