Hot Water Tank Lighting Instructions

How do I light my hot water tank?

I get asked this question a lot from my customers. Here are my hot water tank lighting instructions.

Lighting your hot water tank is easy, but you have to know a few things before you begin.

Is your hot water tank a natural draft unit or a power vented unit?

Don’t let that question scare you!

I am going to explain to you how you can discover that information by yourself easily and quickly (with pictures).

Hot Water Tank Lighting InstructionsThe picture that you see at left is a power vented hot water tank.

I want you to take note of the black plastic motor on top that is connected to the white piping. Also note that the motor is plugged into the wall.

That black plastic motor on top is the power vent motor.

More importantly is the white plastic exhaust pipe attached to the black plastic motor.

If your water heater has a white plastic exhaust pipe, it is a power vented hot water tank. 


The picture that you see at the right is a natural draft hot water tank. It is beside Hot Water Tank Lighting Instructionsthe furnace.

I want you to note the shiny metal pipe that is attached to the top of the hot water tank.

Notice also that there is no black plastic motor. There is no white plastic piping attached to the top of the water heater.

If your water heater has a shiny metal exhaust pipe, it is a natural draft or direct vent water heater. 

Why is it important to know if your water heater is a natural vented or a power vented water tank?

So that you can make your first diagnosis of the problem!

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Direct Vent Vs. Power Vent

Let’s start with the reason that you are here reading this article.

I assume that you currently have no hot water at the taps. Someone has told you to make sure that the pilot light is lit on your hot water tank.

You then searched the internet to get instructions on how to light your water tank because you’re not sure how.

The first step is to determine if your hot water tank actually has a pilot light.

If your hot water tank is power vented, it does not have a pilot light that has to be lit. 

Power vented hot water tanks use a device known as a Hot Surface Ignitor, or a HSI, to automatically light the fuel when needed.

The only hot water tanks that have a pilot light are the natural vent or direct vent types.

Congratulations! You have just made your first official equipment diagnosis.

If you have a power vented hot water tank and there is no hot water, there is likely a problem with the hot surface ignitor.

Therefore you need to call in your service company and have them look at your water heater to fix the problem.

On the other hand, if you have a direct vent style of hot water tank, you can now proceed to lighting the pilot light.

Lighting A Hot Water Tank Pilot Light

What You Need To Do First

At the bottom of your hot water tank you will find the gas valve, a removable metal door, some small pipes, and usually (not always) a small viewing window.

I’ve included three pictures to clarify this for you.

If you look into the window you should be able to see a small blue flame. If you don’t see the flame burning then you know for certain that the pilot is not lit.

Congratulations! You’ve just made your second diagnosis.

On the top of the gas valve you will see a round knob. It has a pointer on it. I want you to rotate the dial pointer to the “pilot” position on the gas valve.

What You Need To Do Next

I want you to push down on the knob momentarily. If you rotated the dial to the correct position on the valve, it should push down about 1/4 of an inch.

If it doesn’t push down at all, you will have to re-align the pointer on the knob with the word pilot that is clearly stamped on the gas valve body.

I want you to also look for a small plastic button. It is usually colored red, but sometimes may be green or black. This is an electric spark igniter.

It will provide the spark necessary to light the fuel for the pilot light. When you push it down you will feel some resistance, and then you will feel and hear an audible click.

In order to light your hot water tank pilot light, you will have to position yourself so that you can see inside the small window.

Then have to push down on the gas valve knob pointing at the pilot setting. While pushing that knob down, you will have to depress the clicking plastic igniter button between 3 and 5 times.

If you are successful, you will now see the blue pilot light burning in the window.

Do not stop holding the gas valve knob in the depressed position! 

You will have to hold down the gas valve knob in the pilot position for at least one minute or more.

Why This Is Important

There are one of two different types of safety sensors built into a direct vent hot water tank; one type is called a thermocouple and the other type is called a thermopyle.

Regardless of what type of sensor your hot water tank uses, it will require a couple of minutes to heat up from the pilot light before the pilot light will stay lit on its own.

This is the reason that you have to manually depress the gas valve knob after the pilot has been lit.

The thermocouple or thermopyle shuts off the fuel if the pilot goes out so that your basement won’t fill up with un-burnt fuel that can cause an explosion. Therefore, it’s a safety device.

The Next Step

After a minute or more has elapsed, you can stop pushing the gas valve knob down and allow it to return to its original position.

Once the pilot light is lit and stays lit on its own, you can now rotate the gas valve knob pointer to the on position.

If the water temperature inside of the tank is below the gas valve thermostat setting, the burner for the hot water tank will light as soon as you turn the gas valve knob to the on position. SUCCESS! 

What If The Pilot Light Didn’t Stay Lit After I Stopped Pushing On The Knob?

There are one of two reasons why the pilot light will not stay lit. Either you didn’t depress the gas valve knob long enough for the thermocouple to heat up, or the thermocouple has failed.

As mentioned earlier, the thermocouple or the thermopyle is a safety device that prevents an explosion from happening in your home.

If the thermocouple or the thermopyle is worn out, it will have to be replaced by your service provider before the hot water tank will operate again. Sorry for the bad news.

If you would like to read more about our company, you can do so here.

We are hot water tank experts. Read more about how we can help you here.

We are proud to carry the Bradford White and Navien brands of water heaters.

I hope that you found the hot water tank lighting instructions helpful.





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