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A Guide to DIY Furnace Cleaning

A Guide to DIY Furnace Cleaning

On top of annual maintenance, the occasional furnace cleaning can keep your heating system running smoothly. In this DIY guide, we’ll look at how to safely clean your furnace. It can reduce the need for heating and furnace services and help your heating system run more efficiently. Assuming your furnace has been inspected and tuned up for the season, here are some DIY furnace cleaning steps to follow.

Shut Off the Unit

Turn off the furnace’s electrical power and fuel supply. The power switch should be on or near the unit (to be extra safe, you can turn off the circuit breaker to the furnace). Next, turn off the fuel shutoff valve, which is near the oil tank or gas supply line. A ¼ turn of the valve will shut off the gas.

Remove the Combustion Chamber Panel

Once the power and gas are off, lift and pull out the combustion chamber door. If there’s a burner cover, remove the screws holding it in place and put the cover aside.

Clean the Combustion Chamber

Carbon and dirt can build up during the combustion process. As you inspect the chamber, take note of soot, which can cause corrosion and be a sign of hazardous problems. If there is just a small amount of carbon, remove it with a small wire brush. Then, vacuum the burners; tape a 20-inch long, ½-inch diameter drain line to the vacuum hose to reach the back of the burners. Vacuum the base of the furnace and wherever there is dust.

Clean the Blower

Cleaning the blower first requires carefully removing it. If the blower, or squirrel cage, has a control panel in the front, remove the two screws and let this hang from its wiring. Disconnect the blower by removing the two bolts that secure it (using a 7/16-inch socket and ratchet). The component should then gently lift out.

Use a vacuum to clean the furnace blower, avoiding the fan blades, counterweights, and wiring. Clean it thoroughly to make sure the blower stays in balance. Remove any remaining dust and debris with a small brush. With the blower still removed, you can check any connected air ducts for dirt or holes.

Clean the Furnace Flame Sensor

The flame sensor is a rod-shaped part that should pull out easily from its bracket. Use a clean emery cloth to wipe it off. A residue coating can prevent the furnace from lighting. Once it’s clean, slide the sensor back into the bracket.

Dust Off the Pilot

Using a drinking straw, blow any dust off the pilot or, if you have a newer furnace, the hot surface ignitor. Do not touch the ignitor. Follow the manufacturer’s instructions for cleaning it. If necessary, carefully disconnect it before wiping it dry and vacuuming off the dust. 

If you have a standing or intermittent pilot ignitor, you can remove debris with a can of compressed air or an air compressor with a spray nozzle. Direct the air into the orifice by moving the nozzle or straw as close to the open end as possible. Spray gently to avoid any damage.

Change the Filters

If you have an oil-powered furnace, you’ll need to replace the oil filter or impurities can clog the oil-burner nozzle. To replace it, close the oil valve, remove the old filter, and replace it. Next, change the air filter (the simplest step to furnace cleaning), which is recommended every three months (or more often if you have pets).

When to Call a Professional

Assuming you’re familiar with your furnace and its parts, you can clean it in one to two hours. Call a licensed heating technician if you find excessive soot, which can mean a burner needs to be adjusted or the heat exchanger has gone bad. Also, call for help if there’s an issue with the pilot light flame. It should be blue. However, if it’s yellow or burning irregularly, your furnace should be checked by a professional who can provide necessary repairs and avoid further damage or a release of carbon monoxide.

Contact Waldrop Plumbing, Heating & Air

At Waldrop, our experienced technicians install, repair, and maintain furnaces in the Greenville and Spartanburg areas. We recommend furnace maintenance at least once a year. Members of our Family Service Plan receive tune-ups, repair discounts, and priority services. To learn more or schedule a professional furnace cleaning, call (864) 536-0887 today.

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Greenville, SC

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Waldrop has taken care of our HVAC since our house was built (2006). We get maintenance twice a year – spring and fall. This year, Kevin suggested the Phenomenal Aire unit. It cleans the air

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Marietta, SC

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Had the best experience with Waldrop, we will forever be in their debt. Not only the most professional group of men but the most honest, stand by your word company! I would recommend Waldrop to

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A friend recommended Waldrop after he had a visit last week. Our A/C was not cooling as well as it should, and the Split “Smart” thermostat was doing crazy things on the first and 2nd


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