Cleaning: Central Air Unit Maintenance

Without regular cleaning and maintenance, a central air unit could be running at as low as 50 percent of it's intended efficiency. Improper cleaning or not cleaning your central air unit can cost you money, since the unit will be working twice as hard to accomplish only half the task it should. Take the time to do some cleaning – central air unit maintenance is a relatively easy home repair task.

There are two components to a central air unit; the condenser and the evaporator. You’ll need to make sure the entire unit is turned off before touching either of these components; then double check that the power to both the condenser and the evaporator are off.

Evaporator Cleaning

1) Remove the insulation at the front of the plenum, even if it’s been taped in place. Do so carefully, as you’ll need to re-tape the insulation once you’re done. Remove the screws from the access plate behind the insulation and take off the plate. The evaporator unit is usually located inside the plenum space.

2) Using a stiff brush, clean underneath the evaporator unit, using a handheld mirror if you’re having trouble seeing what you are doing. You can slide the evaporator forward slightly if you can’t reach all the way back, but be real careful not to bend the surrounding pipes.

3) Underneath the evaporator unit, there will be a tray which needs cleaning. Place one tablespoon of household bleach into the tray’s weephole, in order to prevent potential growth of fungus. You may need to open the weephole with a piece of wire.

4) Put the entire unit back into place, making sure that you reinstall the plate and the insulation, taping it back down.

5) When you turn on the air conditioner, check to make sure there aren’t any air leaks around the unit. If there are, these can be easily sealed with duct tape.

Condenser Cleaning

1) Whereas the evaporator was probably located above the furnace in your home, in the plenum, the condenser unit will be outside. As a result, it will likely accumulate dust, debris, and dirt from the surrounding area – and your job is to clean the coil located on the intake side of the unit.

2) If there are any weeds or plants that have grown up around the condenser, remove them so that they don’t interfere with the unit’s airflow.

3) Purchase some commercial coil cleaner so that you can clean the coil; you should be able to find this at refrigerator supply depots. The cleaner will come with instructions, and you should afterward flush the coil until it’s clean and allow it to air dry.

4) Remove any accumulated dirt on the fins with a soft brush – and never, ever use a garden hose to clean them. This will simply turn the dirt into mud and cause an even greater problem. Straighten any bent fins with a specialized fin comb, and be careful not to damage any of the fins in the process.

5) Finally, use a carpenter’s level to check the concrete pad that your condenser sits on, ensuring that it is still level. If the pad has settled over the course of the year, lift the concrete pad with a pry bar, forcing rocks or gravel pieces underneath until you level it out again.