How to Clean Windows Type Air Conditioner?
Unplug the air conditioner. Disconnect the power from the unit.
Remove the filter and bezel or cover of the unit if needed. Remove the filter to expose the cooling coils. Additionally, some models require that the front cover or bezel be removed to allow full access to the coil. Usually the cover is secured by screws - some of which become visible only when the filter is removed.
Spray the front coil of the air conditioner with a cleaning agent designed for this use. Home Depot and many other home supply centers and hardware stores sell products expressly for this particular job. These cleaners will help remove odors from deposits of dirt, mold, mildew, cigar & cigarette smoke, etc. from the coils. Use care to see that only the coils are covered with the cleaner. Prevent foam from spraying electrical wires, controls or other parts. Foaming type cleaners will work best only when used as directed.
Clean the filter. Clean the filter with plain water or replace if missing. A clean filter is a must. It is far easier and cheaper to remove and clean the filter every 15 hours (more or less depending of dust / dirt levels in the space) than to clean the air conditioner with a foaming cleanser. If the filter is suspected of contributing to odors, soak and wash with a small amount of scented dish soap or laundry detergent.
Replace cover and filter and restore power after about 10 - 15 minutes.
Run the air conditioner. Set the unit to "Cool" and adjust the thermostat to coldest setting. Warm, humid air in will condense when passing over the cold coils. The condensate will rinse the dirt and foam from the coils, and collect in the drip pan. The drip pan will drain outside - but only if the air conditioner is installed properly (back tilted slightly downward to the ground).
Repeat if necessary. If the air-conditioner has been neglected, it may require a second application to produce cold air and be free of odors. Wait until the coils are free from foam before re-applying. If the unit makes cool air but fails to make condensate to wash the coils, it may be due to low of humidity. In low humidity conditions, it will take longer to rinse the coils. If the unit fails to make cool air, it has likely lost the refrigerant charge or the compressor has failed.
Shut the unit off and disconnect power.
Inspect the outdoor coils.
Clean the outdoor coils if desired. The outside coils are exposed to rainwater and may not need cleaning. If unsure, or in a dusty or dirty area, it may help to clean them. Apply foaming cleaner with the unit off. Allow 10 - 15 minutes for the foaming cleanser to work.
Rinse foaming cleanser away with garden hose. Since no condensate is formed on the outdoor coil when the unit is run, it will need to be rinsed manually. Do not force a direct a stream of water into the coils, but merely allow the foam to float away as the water is allowed to flow over the coils.
Reconnect power and test. Set to cooling and adjust thermostat to a low temperature. The discharge air should be cold and smell clean. If not, it is probably time for service or replacement.
Know when it's time to get a new one. Maintenance is great and recommended, but sometimes, it just can't be fixed.