How to Clean the Condenser on a Lennox Elite Series Furnace

Turn off the system so it is not in operation during the cleaning process. Shut off the breaker feeding the system to prevent an electrical accident while cleaning.

Wipe down the condenser with a damp rag to eliminate basic dust and dirt buildup. Use a scrub brush on the coils to remove more stubborn dirt. In many cases, this is enough to keep the condenser clean if done on a monthly basis.

Apply a coil-cleaning foam to the condenser if more stubborn dirt and deposits remain. The foam sits on the coils for several minutes and dissolves foreign material in the process. If you don't have foam, use warm water, several drops of dish soap and a scrub brush to clean them, but the foam is usually more effective.

Vacuum the condenser with a shop vacuum to remove the majority of the foam and the dirt.

Rinse the condenser with water to remove any remaining chemicals.