Conditioning Your Conditioners > Handyman Club of America

POSTED BY: Don Ciske, Club Member
June 28, 2007

Don't get steamed if your central air conditioner or room AC unit doesn't cool. And don't blame the unit, either. Instead, ask yourself when you last took an hour to perform some basic yet vital maintenance to keep it blowing cold.

Most residential air conditioners are either central air systems or room units. Both require some of the same maintenance steps. Here's how to keep your AC running and yourself comfortable.

Central air conditioners
A central air - conditioning system has two parts: an outside box that houses the compressor, condenser coil, motor and fan and evaporator coils that are inside the furnace plenum. The maintenance you can perform focuses primarily on the outdoor components.

A central AC needs good ventilation to perform well, so start by clearing away foliage that comes within 12 to 18 in. of the unit. Next, shut off the power to the unit. There should be a disconnect box mounted on the house within reach of the AC. Now you can access the internal parts.

Remove the cover. (If your AC does not have a removable cover, consult the owner's manual or call a service technician.) The motor is usually attached to the underside of the cover, and you can pivot the whole thing out of the way. Be careful, however, that you don't touch any electrical circuitry inside! Capacitors (see photo) hold a charge even after the power is turned off.

First, lubricate the fan motor. Look for ports with plastic caps covering them, or for the word "OIL" stamped on the motor housing. (If you have a newer model, the motor may have sealed, self - lubricating bearings.) Remove the oil port caps with needlenose pliers and set them aside for reuse. Add 20W nondetergent motor oil to each port. You can also use 3 - in - One machine oil, which comes in a blue can. Don't use 3 - in - One penetrating oil, which comes in a red can. It's too thin to lubricate an electric motor properly.

The next step is to clean the inside of the unit and vacuum out loose debris. The goal is to flush the debris trapped in the fins out the way it came in, so spray the fins from the inside out with a garden hose or pressure washer. When you're done, replace the cover.

The last step is to install a new filter in your furnace. A dirty filter prevents air from efficiently reaching the evaporator coil, which can lead to a damaged compressor. Without proper air flow, the evaporator coil can freeze over and leave you with 20 lbs. of ice on the coil!

If the power to the air conditioner has been off for the winter, restore it eight to 24 hours before you plan to turn on the unit. This allows time for the heaters in the base of the compressor to drive the refrigerant out of the oil that naturally migrates into the compressor.

Room air conditioners
Some of the required maintenance for a room air conditioner is similar to what's needed for central units, so we won't duplicate steps in detail. There are a few, however, that deserve special attention.To make cleaning easier, take the unit out of the window and place it on a workbench. Keep it unplugged, too. Start by removing the housing, noting any unusually long or short screws. A common - and potentially disastrous - mistake in reassembly is to put a long screw in a hole with shallow clearance. An oversized screw can puncture a coolant line, resulting in a difficult and usually expensive repair. Motor lubrication in a room unit is only required every couple of cooling seasons. Again, use 20W nondetergent motor oil or oil suitable for electric motors.

To clean the condenser fins properly, loosen the mounting screws or other fasteners on the farthest end of the compressor. On some models, you may need to loosen or remove the fasteners on the end nearest the compressor as well. Loosen the condenser coil. Support its weight with one hand and gently pull it outward to allow access with a brush. Don't exert too much pressure here or you could kink or snap the coolant line. Brush parallel to the fins with a long - handled wire brush to remove dirt, seed fluff and other debris.

The fins on the evaporator coil (the one that gets cold and sits closest to the interior grille) typically don't get as dirty as the condenser fins because they're protected by a filter and are not exposed to the elements. You should, however, clean this filter with soap and water every month or two during the cooling season.

As a rule, you should oil a room air conditioner's motor and clean its fins every two to three years. If you live in an area with a lot of dust or cottonwood fluff, however, annual cleaning might be required for reliable operation.

Club member Don Ciske repairs residential and commercial air conditioners in Arden Hills, Minnesota.

Comments

By spitfire Wednesday, July 21, 2010 4:31 PM

HOW TO INSTALL ??? WARE THE OLD ONE US TO BE

By pbender1 Thursday, July 28, 2011 7:56 PM

How do you install a new central air unit.

By dyoung18 Thursday, August 18, 2011 4:58 PM

Installing a window unit is usually a matter of providig proper support and weight distribution, and having a VERY slight tilt toward the outside, to allow condensate to drain properly. If your question involves installing a central air unt, this not only SHOULD be left to professionals, it MUST be. removing an old condensing unit requires a set of skills and equipment that cannot be found at your local home imprvement stores, and working with the refrigerant that is contained inside requires (by law) a person certified in refrigerant handling per EPA Section 608. Not to mention that to properly install the new one requires knowledge of refrigeration equipment and charging procedures.

By dyoung18 Thursday, August 18, 2011 5:13 PM

One thing I would open for discussion in this article, and I am not calling anyone wrong, on the contrary I think the information you gave is excellent Mr. Cisk, but, the porton that discusses back-flushing the condenser coil (washing it from the inside out) it is mentioned that a garden hose or pressure washer will suffice.... If anyone is cleaning their own equipment, do yourself a favor and stay away from pressure washing it. The thousands of little fins you see when you look at the coil act as a radiator, releasing heat that has been absorbed in the refrigerant from the inside of your home, and the compression cycle. If Air cannot move over these fins, the buildup of heat and pressure in the system can be a death sentence for your compressor. this is the reason that cleaning the coil is a good Idea, it gets all of the dirt, hair, plant fibers, and whatever else, out of the way, so that the air can flow across the coil unrestricted. I have seen Home after Home where someone (understandably) thinks their pressure washer will do the best job, but the level of pressure generated is too high, and bends the fins over. EXTREMELY bad and usually a large percentage of the coil's surface area is affected. with the fins bent over, the air cannot flow, and the purpose of cleaning the coil is defeated. the bad news is that when the fins are damaged to such a large degree, the cost to have us repair the unit is either going to be prohibitive, or in the worst cases, repair attempts are a lost cause. If you know how to use the washer properly and cautiously to avoid damaging your coil, congratulations on your talent, and enjoy blasting the muck out of your unit. Otherwise, please stick to a garden hose with a standard sprayer attachment.