Sputtering Furnace? Fuel Line Bleeding Basics

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Your home's furnace should run consistently when you turn it on. The burner flame should be steady when the fuel supply is consistent. If your furnace fires up and you notice it sputtering, you should check the burner flame's condition. Here's what you need to know about a flickering, sputtering burner flame on your home's furnace.

Why Would The Burner Flame Sputter?

The most common reason for sputtering and flickering on the furnace burner flame is a disruption in the fuel supply. Whether it's an oil or gas furnace, when that fuel isn't flowing consistently, the flame can't burn steady.

In most cases, the disruption is caused by air pockets in the lines. Air pockets will interrupt the burner flame because they cut off the fuel supply when the air pocket reaches the burner. It's important that you address these air pockets as soon as possible to keep your furnace running as it should.

What Should You Do About Air Pockets In The Fuel Supply Line?

If your furnace is sputtering and you suspect that there's some air in the supply line, you can try to bleed the line before you call for furnace repair. Sometimes, bleeding the line will solve the problem. 

However, if your furnace is a boiler unit that has a two-line supply system, these units are supposed to bleed themselves. In those cases, try hitting the reset button a couple of times to see if it resolves. If it doesn't, reach out to a furnace repair technician right away.

For single-line systems, you'll need to manually bleed it. Find the bleeder valve on the fuel line. It should be close to the burner unit. Attach a small hose to the screw on the bleeder valve, then run that hose into a clean bottle. 

Place a wrench on the bleeder valve, but don't open the valve yet. Press the reset button on the furnace burner to start the furnace. As soon as the furnace starts up, open the bleeder valve. Watch the fuel as it flows from the hose, closing the valve after a few seconds. 

When the fuel starts flowing clear, which means it's free of air bubbles, your furnace should run consistently.

What If Bleeding Doesn't Solve The Problem?

If you've bled the furnace and it's still flickering, that could mean that you have a loose connection or a crack in your fuel supply line that's permitting air into the line. You'll need to reach out to a furnace repair technician right away to find the source of the problem and fix it.

  


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