A Five-Step AC Cleaning and Maintenance Guide

The home Air conditioner ( AC) needs regular maintenance to perform its job efficiently. Indeed, most people forget about their AC unit once the season has come to an end. While the AC is being used, dirt and debris are being drawn into the outside unit by the running fan motor. Furthermore, even when the AC is not in use, falling leaves and other plant material make their way into the unit, where they collect, decompose, and reduce the life of the AC.

With a few simple tools and a garden hose, anyone can perform AC maintenance, and add years of life to their unit.

Materials List

• Garden Hose with spray nozzle attachment

• Regular Screwdriver (Flat-head type)

• Small Socket set or Nut-Driver set (optional)

All outside AC units have removable covers. Some units are round and some are rectangular, but they all have covers that can be removed. Usually these covers are held into place with several small sheet metal screws that can be removed with a regular (flathead screwdriver) or a small (1/4 inch) socket. However, some AC brands may incorporate the use of clips to hold covers into place.

Step 1: Disconnect power to the AC unit

Disconnect power to the AC unit by removing the main disconnect at the Service Disconnect Box. This box is typically located within three (3) feet of the AC unit. Just follow the large cable coming from the AC unit, and it will lead you to the box. A typical box is shown in photo #1. It has been opened and the main disconnect is being pointed out.

There is a spring-loaded latch that protrudes through the front of the box that allows the box to be pad-locked. Using your finger, find the latch-release located on the underside of the box, and push it toward the back of the box. You will note that the protruding portion disappears. Using your other hand, pull the box cover down, and then flip the cover open.

Once it has been opened, take hold of the ring and pull straight back to remove it. Once removed, all power to the outside AC unit is cut off. Close the box to prevent over-spray water from entering the Disconnect Box during AC maintenance cleaning.

Now is a good time to take a look at the underside of the disconnect. Some older style disconnects will have two (2) fuses mounted to the underside. If they are there, take note of the information printed on them, and purchase some replacements to keep handy. Aging fuses will become weak during periods of high heat and/or high AC use, and it is not uncommon for one of the fuses to fail. A failing fuse will prevent the AC from working, but not entirely. Usually the compressor will no longer be able to turn on, but the fan will continue to work. Your home will not get cool, and to the uninitiated, it would appear as though the AC had failed.

Step 2: Cover Removal and Cleaning

Photo #2 is a view of the AC’ s compressor compartment with that portion of the AC’s cover removed. Notice the leaves, dirt and other debris that have collected. You may also note that a portion of the coil has been covered over by accumulated dirt and grass. An accumulation of debris around the coil restricts airflow and causes the AC to lose efficiency, which in turn raises your electric bill.

Using your hands, collect and scoop out as much of the accumulated debris as possible. Because the power has been disconnected, the possibility of electrical shock has been removed. However, take care not to pull or disconnect any of the AC’s wiring. Once the debris has been removed, its time to unfasten the cover that houses the fan compartment and coil.

The use of an assistant may be needed for this next part. Most AC units will have the fan motor attached to the underside of this top-cover, if this is the case, then it will be heavy. Additionally, the cover may need to be manipulated slightly to allow the fan blade to pass through the opening in the frame without getting caught. Because the fan is connected to the AC by its wires, the cover cannot be completely removed from the unit.

Have the assistant to hold the cover with the edge of the top-cover resting on the main AC unit frame (see photo #3). The interior of the AC and the unit’s coil will now be exposed for maintenance. Photo #3B shows the interior of the unit, and all the debris that has collected.

Using your hands, scoop out as much of the debris as possible. Prepare the garden hose by attaching the spray nozzle, and select a light-fan type spray patten as shown in photo #3. Spray the interior of the AC until the remaining dirt has been washed away and has drained through the drain holes (see photo #3).

Angle the spray as shown in photo #3 , and gradually move the spray from top to bottom in order to remove the dirt from the coils. Because the air-flows from outside to inside, the cleaning must be performed in the opposite manner to ensure trapped dirt and debris are removed from the AC’s coil. Continue this action with overlapping sweeps until the entire coil has been cleaned. Be careful not to deform any of the coil fins because bent fins will restrict the air-flow through the coil.

Ensure all the drain holes are clear to make sure that falling rain and melting snow will be able to drain from the AC. If restricted, moisture will accumulate and promote rusting of the AC unit. Once the coil and the AC’s interior have been cleaned, use the garden hose to spray under the AC unit to wash away the debris that has collected there.

Next, using the same spray setting as before, begin cleaning the compressor compartment. Be sure to spray into the corners where the coil and AC frame covers meet (see Photo #4) because this area is prone to heavy collections of dirt. Again, ensure the drain holes are clear and that water flows freely from them.

Take care not to directly spray water onto the electrical section of the AC if it is exposed. Should that happen, then the AC unit will need to dry for several days before it can be started up. After you have finished cleaning the compressor compartment, spray under the AC unit to remove the debris that has collected there. Let the compressor compartment air-dry for about 20-minutes before replacing the cover.

Step 3: Checking the Fan Motor

Before setting the top-cover and fan combination back into position, give the fan-blade a spin. Use light pressure when spinning the blade. It should spin effortlessly, and continue spinning for a few seconds. A freely spinning fan-blade indicates a fan motor that is properly lubricated. However, if the fan-blade spinning is labored, or it spins and abruptly stops, then it is ready for maintenance. At this point, if fan motor servicing is ignored, the fan motor will soon “freeze-up” and burn-out. Fan motor maintenance is covered in a different article titled AC Fan Motor Cleaning, Maintenance, and Oiling.

Step 4: Replacing the AC Covers and Screws

Becareful not to deform the fan-blade as the top-cover is being put back into place. Ensure that all the sheet metal screws have been replaced, and that they are tight. If using a socket, be careful not to over-tighten the screws because they will strip, and you will not be able to tighten the cover(s).

Step 5: Reconnect Power to the AC Unit

Plug the disconnect back into the Disconnect Box, and securely close the cover.

AC Maintenance is a simple task that can add years of life to the unit, and help keep electric bills down. Moreover, some simple checks performed during cleaning can assist in spotting future problems that can cause you to spend money in repair bills. Perform this cleaning and maintenance procedure at least once yearly to keep your AC running efficiently.