How to Clean an Oil Furnace Chimney

Chimneys require cleaning to remove soot.

Oil furnaces create soot from the combustion process. The soot collects on the inside of the exhaust stack and the chimney. The typical oil furnace has a metal exhaust stack that empties into a masonry chimney. The masonry chimney moves the combustion gases outdoors. Over time, during a winter heating season, the interior of the chimney will accumulate soot. The soot accumulation will decrease the oil furnace's efficiency. You must clean the chimney annually for it to operate properly.

Things You'll Need

• Screwdriver
• Chimney brush (same size as chimney opening)
• Extension poles
• Flashlight
• Vacuum cleaner

Instructions

1. Shut off the main power to the oil furnace. If you don't turn off the furnace, you could get hurt.

2. Find the outdoor exhaust point of the chimney. Remove the chimney cap. In most cases, two screws hold the cap onto the chimney structure.

3. Attach the chimney brush to the first extension pole. Insert the brush into the chimney and push down. Add the next extension pole to the first. Push the brush down. Continue adding extension poles until the brush reaches the bottom of the chimney structure.

4. Pull the brush and extension poles up and out of the chimney. Insert the brush again and push down. Continue to scrub the chimney in this manner several times. Remove the brush from the chimney. Shine the flashlight down the interior of the flue. Inspect for any errant soot on the sides of the chimney. Repeat the scrubbing process until all soot has been removed.

5. Open the lower clean-out door of the chimney. Vacuum all soot from the area. You may have to have to scrub the chimney one more time if the built-up soot is heavy. It is better to over-clean the chimney than to leave any remaining soot clinging to any portion of the interior flue.

6. Close the lower clean-out door. Replace the chimney cap. Go to the oil furnace area.

7. Vacuum and clean the exhaust-stack damper opening. Heavy soot build-up will interfere with the operation. Do not adjust the damper settings.

Tips & Warnings

• Inspect all brick and mortar joints for cracks and damage. You must also inspect metal stack piping. Do not take apart any sections of the stack piping inside the home. Leave interior pipe maintenance and cleaning to a certified technician. Dangerous flue gases will escape if the interior piping is not properly sealed.

• If you feel uncomfortable cleaning the oil furnace chimney, contact a certified technician to perform the job for you. In many cases, this may be a part of the annual service maintenance contract with a heating technician.

References

• "Oil Burners"; Edwin M. Field; 1978
• University of Missouri: Heating System Maintenance
• Michigan State University: Maintaining Conventional Residential Oil-Fired Heating Systems
• University of Missouri: Cleaning Stovepipes and Chimneys