Do you need to bleed your gas furnace but aren’t sure how? Then take a look at the instructions in this article that will explain how and why you should get the job done.

If you haven’t used your gas furnace in a few months there could be air in the line. Here’s how to bleed a gas furnace:

  1. Repeatedly press the igniter button for 45 seconds
  2. When the pilot lights, press and hold the igniter button for 45 seconds
  3. Repeat steps 1 & 2 up to 3 times

Bleeding a gas furnace is a job that has to be done carefully. But it is also a super simple DIY task. Take a look at these steps in detail and find out more about the importance of bleeding a furnace next.

Simple Steps to Bleed Your Gas Furnace

Are you having trouble getting your gas furnace started?

So you’ve had a spell of nice weather and you haven’t needed to put the heating on for a couple of months. But as the nights now get a little cooler, turning the gas furnace on in the evening is a nice way to make the house feel cozy.

If you are having trouble getting your gas furnace to start then it may need bleeding. This job is simple but should be done carefully. Here’s everything you need to do to bleed your furnace and get it up and running again.

Step #1 Ventilate the Area

This first step is one of the most important to ensure your safety. That is to open the windows and doors. You should make sure that the room you are in is well-ventilated for the duration of the job. There shouldn’t be any open flames present. This includes candles, kerosene lamps, oil lamps, or anything similar.

furnace next to a window
Keep your windows and doors open while you work for good ventilation (even if it’s cold!)

Step #2 Open the Valve Assembly

The next thing you will need to do is to open the valve assembly on the gas line. You should be able to open and turn the valve assembly so that it stays in the “ON” position.

Step #3 Push the Igniter Switch

Next, you need to push the igniter switch repeatedly for 45 seconds or press and hold the switch in the “ON” position. As you do this, you should see a blue spark at the pilot assembly.

Step #4 Push and Hold the Gas Valve Control Knob

Then, push and hold the gas valve control knob. Turn it as you push and hold it so it stays in the “ON” position.

Step #5 Push the Igniter Switch

As you push and hold the gas valve in, you will need to push and hold the igniter switch. Do this until the pilot valve ignites*.

*NOTE: It could take up to 10 minutes for the pilot valve to ignite. How long it will take to ignite will vary depending on how much air is in the gas line.

Step #6 Continue Pushing the Igniter Switch

Once the pilot valve ignites, continue to push the igniter switch for 30 seconds more. As you do this, turn the gas valve on.

Step #7 Check How Your Furnace Ignites

If the fire remains alight after you have released the ignition, the gas is flowing properly again. You should now be able to start your gas furnace without any issues. If the furnace does not ignite easily, repeat steps 1-6 again*.

*NOTE: If your gas furnace has been out of operation for more than a few months, you may need to repeat steps 1-6 up to 3 times for it to start working again. If the gas furnace does not ignite easily after you have done this, you will need to contact a technician. This could indicate that there is a more serious problem with it.

furnace with brass surround
If the fire stays lit, your gas is flowing properly again

Why You Need to Bleed Your Gas Furnace

Bleeding a gas fireplace is just another job we have to add to our never-ending list of household chores. Because this is not a job that you have to do often, it would be easy for your furnace to get neglected. So, why is it so important that you bleed your furnace?

It is important to bleed your gas furnace in case there is air in the gas line. If there is, you will not be able to ignite your gas furnace.

But what causes this problem? If there is air in your gas line it means that there is a void in the line. The void will be between the gas valve and the pilot assembly. This is caused by infrequent use of the furnace. This could be for the following reasons.

  • You didn’t use your furnace over the winter
  • You didn’t use your furnace for two consecutive months or longer

Bleeding your gas furnace will make sure that it ignites immediately.

gas furnace
Bleeding your gas furnace ensures that your furnace ignites easily

How Often Should You Bleed a Gas Furnace?

You should make bleeding your gas furnace part of your annual furnace maintenance. Doing so will make sure that it stays in tip-top condition and ignites quickly. Bleeding your gas furnace once a year will also help to prevent issues and breakdowns. 

Asides from bleeding the furnace, you should also do the following maintenance on your gas furnace.

  • Routine cleaning
  • Annual chimney sweeping
  • CO alarm testing

Do You Need a Professional to Bleed a Gas Furnace?

Bleeding a gas furnace is not a job that requires a professional. This is true as long as you follow the instructions carefully when completing the job. It is also important that you bear a few safety protocols in mind. The following tips will ensure that you stay safe while bleeding your gas furnace.

  • Make sure the area that you are working in is well-ventilated. Keep the windows and doors open while you work.
  • Ensure that there are not any open flames on the premises while you work. This includes cigarette lighters, candles, oil lamps, and anything similar.
  • Follow the user manual for your gas furnace. Any specific instructions tailored for your furnace will be included here. You must take a look at them before you start the job.
  • If you smell gas, that means that there is a leak. Immediately evacuate the house and contact the emergency services.
  • Check your propane tank is in proper working order before you attempt to use it
  • Keep your gas furnace clean, this will make sure that it does not become clogged. A clogged firebox could cause a house fire and carbon monoxide buildup. You can keep the fireplace clean by doing the following:
    • Cleaning the vents
    • Emptying the ashtray after each use
    • Vacuuming and cleaning the firebox
    • Keep the fireplace flue clear of debris
cleaning the fire box
Regular cleaning of the firebox keeps the furnace safe for use


On a cold winter evening, no one likes to fight with a gas furnace that doesn’t want to turn on. That’s why bleeding your gas furnace annually is so important so that you can keep using it hassle-free. I am sure that this article has shown you a simple method that you can use to get the job done quickly and safely.

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Have a great day!