How to Clean an Oil Furnace Heat Exchanger

An oil furnace heat exchanger should be cleaned once a year.

It is critical that the soot buildup on the inside of the heat exchanger in your oil furnace is removed once a year. Large amounts of soot can raise the heating bill, increase the likelihood of fire and force the release of carbon monoxide into the home, which can be deadly. A qualified technician should do flame adjustments, but most people can clean the soot from the heat exchanger.

Things You'll Need

• Owner's manual for the oil furnace
• Small, stiff-bristled brush
• Flashlight
• Wet/dry vacuum cleaner
• Soft cloth
• Dust mask
• Safety glasses

Instructions

1. Locate and open the clean-out panel on the oil furnace. A lowboy design furnace will have the door on the front. A horizontal design will have the clean-out panel on the side. Consult the owner's manual for the exact location on the model you're cleaning.

2. Use a small brush to loosen soot on and around the heat exchanger, located inside the unit. Some areas are difficult to reach, but a good flashlight will help locate the hidden soot.

3. Use the wet/dry vacuum cleaner to suck up the built-up soot. It may require alternating between vacuuming and brushing to remove most of the soot debris. Wipe the heat exchanger down with a soft damp cloth before closing the clean-out door.

Tips & Warnings

• Clean the heat exchanger annually to prevent large amounts of soot from clogging up the heating unit. The piping and vents will need to be cleaned as well to remove all of the soot and creosote from the system. The U.S. Department of Energy gives excellent recommendations to improve energy efficiency and savings with oil furnaces.

• Wear a dust mask to keep soot from getting into your lungs. Wear safety glasses to protect your eyes from soot debris.

References

• Heat exchanger cleaning
• Oil furnace care

Resources

• U.S. Department of Energy efficiency recommendations