DIY Air Conditioner Evaporator Coil Cleaning
This article is a compliment to “How To Clean Central A/C Compressor Coils”. For the purpose of this article, we’ll be discussing air conditioner evaporator coil cleaning inside of the air handler of a split central air system, typical of air conditioning systems in the Dallas area. My central air conditioning system happens to contain a natural gas furnace for heating.
Your air handler is composed of a blower motor, the furnace, and the evaporator coils. You can easily see which compartment your evaporator coils are located inside of by looking for the refrigerant lines and where they come out of the air handler. There are 2 refrigerant lines. One is larger and one is smaller. The larger one is low pressure and contains freon in it’s gas form. It will feel cold when your air conditioner is running. The smaller one is a high pressure, high temperature line that contains refrigerant in it’s liquid form.
As air is blown across the evaporator coils, the air around it cools and blows that cooled air into your home through the duct work. When the evaporator coils begin to become coated with dirt, dust and grime, they don’t cool the air flowing over them efficiently, causing your system to work more to cool your home.
Air Conditioner Evaporator Coil Cleaning Tools You’ll Need:
1. No-rinse spray on foaming cleaner for coils
2. A few basic tools
3. Roll of foil tape
4. Bleach/water mixture in a garden sprayer
5. Portable vacuum or shop vac
Here’s what to do:
First, turn the thermostat to the off position. You can also flip the switch located near your furnace to shut off power to your unit.You’ll need to locate the evaporator coils within your air handler. This will be the section where the freon lines enter. There is a sheet metal panel attached to the air handler which will need to be removed. It’s attached by sheet metal screws, and the edges are usually taped with foil tape to prevent too much cold air from escaping. Be careful not to damage your freon lines as you remove the panel.
Your evaporator coils should be visible and you should have enough room to clean the coils. If your unit does not allow enough room to comfortably work, I recommend hiring a pro. At the least, you can visually inspect your coils once the panel is removed.
Begin by spray a foaming cleaner on both sides of the coils to loosen the dirt and grime. You can get a no-rinse foaming coil cleaner which will do the job just fine. I used WEB WCOIL Coil Cleaner on this unit. An evaporator can remove many gallons of water from the air inside your home in a day! The condensation will more than rinse the coils. I always spray the coils with a mixture of bleach and water using a garden sprayer to help inhibit mold growth. About 1 cup of bleach to a gallon of water works very well. Never use acid based chemicals to clean your coils!
(Even though vinegar is acidic, you could use it as an alternative, but the smell isn’t very pleasant. Either way, clean your coils on a warm day so the condensate will help rinse everything.)
Then, I pour the remaining bleach/water mixture I have left in my garden sprayer into the drain lines to keep them free of algae buildup. A clogged drain line can cause your drain pan to overflow and cause extensive ceiling water damage. I used the remaining bleach/water mixture from my garden sprayer and poured it directly into the drain pan. The house will have a very mild bleach aroma for about a day. There is no concern though, it is a very mild smell that dissipates quickly.
When you are done, replace the panel, screws and use foil tape to seal the edges of the panel.
Panel replaced, edges taped and I felt along all sides to be sure I did not feel any cold drafts!
Things to look for:
When your air handler is open you can look inside and do a visual inspection of the amount of rust, grime and mold accumulated on the evaporator coils. Also check the pan for rust and holes. Perhaps the best pan to have is a plastic drain pan, which are available. Hire a pro to replace the pan or coils when needed. There should also be a secondary pan under the air handler equipped with a cutoff switch in case the evaporator drain pan fails.
Air conditioner evaporator coil cleaning should be performed twice yearly. Once in the spring before the cooling season and once in the fall before the heating season. Good maintenance will save you money every month on your utility bill and keep you from replacing major parts on your system prematurely. Heating and cooling your home is the single highest expense most homeowners have on a month-to-month basis.
Air conditioner evaporator coil cleaning is not a difficult job! Take your time and do a good job and expect to spend an hour or more your first time through. As you gain confidence and experience you’ll get faster. And you’ll always know how the internal parts of your air conditioner are doing.
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So there you go. Feel free to send in your comments and good luck!