How to Restart a Furnace After Running out of Oil

Co-authored by wikiHow Staff

Last Updated: May 21, 2022 Approved

When your furnace runs out of oil, it may or may not restart on its own after being refilled. If your furnace has a reset button, using this feature may restart things with little effort. If the reset button fails, you'll have to ready your fuel line to for bleeding, then bleed the line to restart the furnace. If your furnace still refuses to light, troubleshoot problems like faulty lines or filters.

Part 1

Part 1 of 4:

Utilizing a Furnace Reset

1
Place a container under the bleeder pipes, if necessary. If your furnace has a reset function, there should be two copper lines running from your oil tank to the pump. If your pump does not have pipes, the oil may bleed from a fixture. You may need to put a container underneath this fixture to catch bleeding oil.
2
Press the reset button. Some furnaces may not be equipped with a reset button. However, if yours has this feature, you should find it located on the furnace, usually close to the oil tank. In most cases, this button is red. Push it once or twice.^{[1]
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- If you cannot easily locate the reset button on your furnace, consult its user instructions. This part should be described or clearly marked on diagrams.
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3
Check fuses and breakers when the furnace doesn't light. If the furnace doesn't come on in 60 seconds after pressing the reset, check the furnace fuses and circuit breaker. Replace or reset necessary fuses. Try to reset the furnace one more time. If the furnace does not relight, bleed the fuel line as described.
- When your furnace is running, a lack of oil spray on the inside of the furnace is another indication that you need to bleed the fuel line.^{[2]
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Part 2

Part 2 of 4:

Readying the Bleeder Valve

1
Gather your supplies. You may have some of these supplies already in your household. Those you are lacking can be bought at your local hardware store or home center. To bleed your furnace you'll need:
- ¼ in (.64 cm) flexible tubing
- Container (like a coffee can or a liter soda bottle, to catch oil)
- Oil absorbent material (like sand, non-clumping clay, or cat litter)
- Rag (to wipe up excess oil)
- Suitable wrench (generally 3/8th's size)
2
Turn off your furnace. There should be a toggle switch on the furnace for this. Toggle the furnace to "Off." The reset button may have automatically turned off your furnace. If so, this is usually indicated by a red "On" light next to the reset button.
- When the auto-shut off for the reset button is engaged, you don't need to turn the main On/Off toggle switch to "Off."^{[3]
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3
Locate the bleeder valve. This is generally positioned on the side of the fuel pump, usually at 4 or 8 o'clock position. The bleeder looks like a grease fitting with hex nut shape, like one that a ³⁄₈ inch (1.0 cm) wrench might fit.
- You should find fuel lines leading to and from the fuel pump. The pump is oftentimes located on the left side of the burner unit.^{[4]
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4
Attach nylon tubing to the bleeder. Place your container on the floor close to the bleeder. Fit the tubing over the bleeder so it hangs down. The tubing should extend to the bottom of your container. This container will be used to catch the oil.
- Choose an oversized rather than undersized container. Oil that overflows your container can make a big mess.
- Use a clean, dry container for bleeding oil from the pump of your furnace. This way, you'll be able to return and re-use the oil after it is drained.
- Draining the fuel line for your furnace can be messy work. You may want to wear a pair of gloves while bleeding oil.
5
Loosen the bleeder. After the tubing is attached to the bleeder, prepare the bleeder by loosening it with a wrench. Turn it counterclockwise to do so. Once broken loose, lightly re-tighten the bleeder with your hands.^{[5]
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- During this process you might hear a gurgling noise from the tubing. This is completely natural.

Part 3

Part 3 of 4:

Bleeding the Fuel Line and Restarting the Furnace

1
Turn on the furnace and open the bleeder. Toggle your furnace from "Off" to "On." Immediately after doing so, open the bleeder valve a half turn counterclockwise. The tubing should eject a combination of oil and air.
- The force of oil and air running through the tubing can cause it to move. You or a helper may want to hold the tubing and container to prevent accidental spills.
- It may be necessary to use the reset button to turn on the furnace. Follow your furnace's user instructions for best results.
- Opening the bleeder valve more or less will increase or decrease the rate at which the oil drains. Adjust this as necessary for your situation.
- The bleeder screw may have to be completely removed to get a good flow. Shut the furnace off once the flow has started. Replace the screw and restart furnace when through bleeding.
2
Resolve locked out reset buttons, if necessary. If you've hit your reset button multiple times, a safety lock out feature may be preventing you from pressing it again. To restore the reset button, press and hold it for 35 seconds, then release.^{[6]
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3
Bleed the line until only fuel comes out. After a few seconds, the bleeder should begin to expel an uninterrupted flow of oil. Allow the line to drain a few seconds after this to ensure all air has been removed. Close the bleeder by turning it clockwise until firm.
- In some cases, especially if the pump is far from the oil tank, you may need to bleed your line into your container several times until all the air is removed from it.
- If there is no discharge from the bleeder, there may be a problem with the pump, a clog in the filter, or damage somewhere in the fuel line preventing it from draining.
- Fuel that has been drained into a clean, dry container can be returned to the fuel tank after it has been drained.^{[7]
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4
Check the burner for ignition. The bleeder valve should be returned to the fully closed position you found it in. The furnace should be switched to the "On" position. At this point, the furnace should relight.
- If the furnace is operating properly, you should be able to view an orange glow or fire through the inspection port located on the front of the furnace.
- If your furnace does not relight, drain the line again as described. You may have to bleed the line several times before it begins working again.

Part 4

Part 4 of 4:

Troubleshooting Your Furnace

1
Verify the condition of oil supply lines. Crushed, bent, or damaged tubing supplying your furnace with oil may be starving it of fuel. Leaking lines may prevent oil from reaching the burner. Brittle, deformed, leaking, or degraded tubing should be replaced.
- Tubing for your furnace can be purchased at most hardware stores and home centers. When replacing tubing, your furnace should be turned off.
- Oil remaining in tubing can make a big mess when being replaced. Lay newspaper, a drop cloth, and/or a container beneath tubing you're changing to prevent a mess.^{[8]
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2
Bleed air from the oil filter. If your furnace doesn't restart after bleeding the fuel line, you may need to remove air from the filter. The oil filter is usually found suspended close to the fuel line either near the oil tank or furnace. To bleed the oil filter:
- Carefully loosen the ¹⁄₄ inch (0.6 cm) bolt on the top of the filter with an appropriate wrench until you hear air escape. Stop loosening when you hear air.
- Let the air drain. When oil begins to bubble around the bolt, tighten it closed to the position you found it.^{[9]
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3
Replace your oil filter, if necessary. Clogged filters can also prevent your furnace from restarting. Filter kits for your oil furnace are available at most home supply stores. Different furnaces will have different filter replacement procedures. Follow the user instructions for your furnace to properly replace the filter.
- Replacement kits generally come with new seals and gaskets for the bolts of the filter. Use these new parts for the best results.
- When reassembling your filter, it's especially important to make sure that all the fixtures and fastenings are snug and tight.^{[10]
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4
Call a professional, if necessary. Bacteria or sludge may be clogging the lines of your furnace. This may require a burner technician, who can blow out and clear the lines. Look for contact information for technicians certified to work on your furnace in its user instructions.

Community Q&A

Question

Why is my inside boiler tank not turning back on?

Johnny The Critic

Community Answer

I've often run into this problem. Power it off at the breaker or power switch and turn it back on after one minute. Press reset - if no restart occurs, hold reset for up to 30 seconds. If that doesn't work, try turning up the thermostat, changing the in line oil filter, making sure there is enough water from the tank, and bleeding air from the water tank.
Question

My fuel oil furnace will often not restart, and I have to hit the reset or, at worst, bleed the line to get it going. When it runs, I hear a whistling sound coming from the copper tubing. Could this be the tubing sucking air and causing the furnace not to restart?

Community Answer

That it could be it. The filter could be clogging. The worst case is that the pumping mechanism is failing, though that's doubtful. Is it running smoothly? It should be regularly cleaned inside, and it wouldn't hurt to have it serviced.
Question

How can I receive gas at a pressure of 12atm?

Community Answer

Try a custom vacuum chamber with a controlled ratio of volume to mass inlet. In a secondary chamber, insulated from the initial point of entry, create an outlet for the altered atms of pressure.

Warnings

Remove oil from plastic containers as soon as possible. Oil dissolves plastic, and the container may lose its integrity in anywhere from a few hours to a few days.

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Always use caution when working with combustible substances, like oil, and fire.

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Make sure the wrench fits the bleeder properly. Don't use excessive force when loosening or tightening the bleeder. If you strip the bleeder, it could be quite expensive to have it drilled out.

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Never add gasoline to a home heating oil tank.

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If you see oil seeping on the floor from around the furnace, stop work immediately. The combustion chamber may be flooded and will need to be properly serviced before attempting to run the burner. You'll likely need to replace the combustion chamber of the furnace.

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