You should refer most serious air-conditioner problems to trained technicians. Keeping the components clean helps prevent most common problems.

To clean the filter, remove it from the furnace or air handler (it’s usually located inside or very near the air-inlet side). Replace a disposable filter or clean a reusable filter according to the manufacturer’s directions.

Clean evaporator or condenser coils by removing access panels and brushing or vacuuming the coils—or use a garden sprayer filled with a mixture of water and detergent to spray from the inside out (be careful not to spray the electrical components). Rinse with a hose (again, avoid the electrical parts). Be careful not to bend the fins or damage the coils. While cleaning the evaporator, check that the condenser drain is clean. If you accidentally bend fins, you can buy a comb made for straightening them.

Cleaning the blower’s fan blades will keep your air conditioner operating quietly. Tighten the mounting bolts and lubricate any oil cups according to the manufacturer’s directions.

Call a technician if you have a defective condenser or any problems with the refrigeration system—this is a closed system that you should not attempt to repair.

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