Keeping An Air Conditioner`s Cool

June 20, 1992|By John Warde, New York Times News Service.

A window air-conditioner should last at least 10 years if properly maintained. Proper maintenance means servicing it at least once a year, either at the start of the warm-weather season or after it. In an especially hot, humid summer, midseason servicing also is recommended.

Before you begin, be sure the air-conditioner is unplugged. Then vacuum the front grille and controls or wipe them with a cloth and an all-purpose household spray cleaner.

Next, remove the grille to clean or replace the air filter. Most grilles are fastened with screws; others spring free when pressed along the top or sides.

If you have difficulty removing he grille, consult the owner`s manual.

(If the manual is lost, examine the grille`s perimeter; pressing with a putty knife in the seam around it may disengage hidden tabs that will free it.)

Air filters should be cleaned or replaced every month when the air-conditioner is in use, even if no other maintenance is performed; it is the most effective way to keep the machine performing at its best.

Before removing the filter, notice how it is held in place so you can reinstall it. Check especially what side faces the room.

To clean a washable filter, the kind made of foam, brush or vacuum away surface dust and wash the filter under a faucet with warm water and household detergent.

Dry the filter by shaking it or blotting it with paper towels before reinstalling it. Appliance stores sell washable and nonwashable replacement filters.

While the filter is out, clean the fins on the evaporator coils by vacuuming them with a soft brush attachment. Be careful not to bend the delicate fins. Bent fins limit cooling and block airflow and can cause a whistling noise when the machine is running.

Straighten bent fins by gently twisting the tip of a kitchen knife between them or use a tool called a fin comb, available at stores selling appliance parts.

At the bottom of the air-conditioner near the fins, you may find a small drain hole that channels condensed water to the rear. Poke a wire or piece of coat hanger through the hole to clear it.

If there is evidence of mold or algae, wipe the bottom of the air-conditioner with a cloth dipped in a solution of chlorine bleach or borax mixed with water.

If water accumulates in the front half of the machine during operation, check the drain hole for blockage. If the hole is not blocked, use a carpenter`s level to be sure the unit slopes properly; it should tilt so the rear is at least a quarter-inch lower than the front.

In very humid weather, water dripping from the outside of an air-conditioner is normal. It is condensation and is overflowing because it accumulates faster than it can evaporate.

But a musty smell coming from the machine is a sign of mold or bacteria growth inside. If the smell persists after the drain hole has been cleared and water ceases to drip from the outside, professional servicing is usually necessary to disassemble the unit for thorough cleaning.

Disassembly is not safe for amateurs because of the danger of electric shock from motor parts even when the unit is unplugged.

Inspect, dust and lightly lubricate other visible components in the air-conditioner, such as louver assemblies that direct airflow. A soft

paintbrush is excellent for dusting. Then replace the filter and grille and examine the unit from outdoors.

For maximum cooling, the exterior of an air-conditioner should be shaded from the sun. Trees, shrubs or an awning can do the job, but they must be far enough away to allow warm air to escape from the machine.

Trim foliage back about two feet in breezy locations and more where air is still. Clean and straighten the rear external fins if you can reach them or if the air-conditioner can be easily taken inside.

Finally, examine the seams and weatherstripping around the air-conditioner and along the window frame. The filler panels on both sides of the machine should fit snugly into the window frame; put new weatherstripping where strips have come loose and renew crumbling putty or caulking compound.

When reconnecting an air-conditioner, be sure that draperies or furniture do not block airflow. Do not operate another appliance on the same circuit while the machine is running; doing so can drain current and possibly damage both appliances.

Ordinary extension cords cannot safely handle an air-conditioner`s heavy electrical load; use a cord made for air-conditioners. Hardware and appliance stores carry them.

Undue humming or other constant noise coming from an air-conditioner usually is caused by vibration. Finding and eliminating the cause can be difficult, but look first for loose fasteners that can be tightened. Also check the thermostat, a bulb or wire on the front of the air-conditioner behind the air filter.

Reattach the thermostat if it has slipped off its bracket. If these remedies do not work, shift the machine slightly or insert shims between the grille and the body.

A clicking noise usually caused by the fan`s striking the housing or another part. Shifting the machine may help. If it does not, soft wire sometimes can be used to tie loose coils out of the way. On an old unit, the fan may be worn and need professional service.