The Most Common Air Conditioning Failures (And How To Repair Them)

The air conditioner is a masterpiece of technological ingenuity that tames inclement weather conditions. Until it doesn't. Air conditioning systems, regardless of the type, have their own set of unique and, often unexpected, problems. And since the majority of American households have at least one air conditioner unit installed, chances are you have experienced failures firsthand. This is especially frustrating if it happens at the peak of summer when you need the cooling breezes the most.

Air conditioning failures come in all forms and degrees of severity. Some, including dirty air filters, drainage problems, and a freezing condenser coil, can be easy to fix without having to look for a technician. But others, such as a damaged compressor and capacitor failure, would call for a professional to handle them. These usually imply that one or more parts of the unit are malfunctioning and should be replaced. Between those two extremes, other problems of mild severity might pop up. Then, you can either put on your technician hat and try to fix it yourself or take the costlier, yet easier, route of calling an expert. Read more to find out the most common air conditioning failures and how to fix them.

It's not normal for water to leak out of the air conditioner either indoors or outdoors. But as you might expect, such mishaps can happen for a wide variety of reasons. If the water leakage is indoors, then the condensate drain pipe, where the moisture inside the AC unit safely drains out in the pan, might be clogged. Fungal build-ups that thrive in humid conditions are often the culprit behind the clogging. Switch off the air conditioner then use the manual to locate the condensate drain pipe. Mix equal amounts of vinegar and water or bleach and water and pour the liquid inside the drain pipe to kill the fungi and unclog it. However, if the drain pipe isn't clogged, then the condensate pump might be malfunctioning, and you'd need to have it replaced.

If the water is leaking from the compressor outside, then the issue could be damaged condensate pans, poor installation of the unit, or the seal has gone bad. Unfortunately, none of these problems should be fixed by consulting the manual and watching a YouTube video. You should turn off the AC unit and give the technician a call.

The AC air filter has one job to do: screen the airflow for specks of dust, lint, pet hair, and dead bugs and keep them from cycling through the house. Over time, the filter mesh can become clogged with these pollutants. It's a slow and steady process, but its impact is decisive. The airflow increasingly diminishes, and the AC takes longer to cool down your home. This, in turn, has other undesirable effects, including but not limited to a spike in the electricity bill, frozen evaporator coils, and acceleration of the wear and tear of the air conditioning unit. 

Air conditioner filters come in two types: replaceable or reusable. Replaceable options can only be used once and you should replace these air filters every one to two months depending on the quality of the air in your home and whether anyone has allergies. But if you have a reusable air filter, sometimes called a washable air filter, you should clean it every few months. Switch off the AC and open the front panel to remove the air filter. Wash it with a mixture of warm water and detergent, then rinse it thoroughly. 

Leaking refrigerant, aka freon, is just as deceptive as a bad capacitor. In both cases, the compressor and the fan motor are working just fine, but the temperature indoors doesn't meet the thermostat setting. However, in the case of the leaking refrigerant, there's a serious health risk involved since the chemical is highly toxic. Some telltale signs that the AC refrigerant is leaking include frozen evaporator coils, dwindling cooling performance, and a hissing or gurgling sound coming out of the condenser.

Freon can leak from the AC unit due to shoddy installation or corrosion of the copper tubes, either because of friction or exposure to acidic chemicals. The system is also more likely to spring a leak if it's an old model where wear and tear has undermined the integrity of its components. Whatever the source, a leaking refrigerant is a serious system failure and you shouldn't try to fix it yourself. Stay away from the leaking AC to limit your exposure to the chemical and call a professional to handle it safely.

It's hard to miss this failure. When you switch on the AC or when the compressor kicks into gear to start a new cooling cycle, the circuit breaker will trip. As with other air conditioning problems discussed here, there's more than one source for this failure. It could simply be a bad or too-weak breaker that's at fault. Dirty condenser coils, clogged air filters, or a malfunctioning fan motor can all increase the power consumption of the unit and cause the fuse to blow. But the origin of the tripping could be more ominous and pricier when you have a failing compressor or a burnt-out motor.

Apart from the clogged air filters which you could clean or replace yourself, the rest of the issues should be handled by a professional. An electrician could replace or upgrade the circuit breaker just for the AC system, thus minimizing the recurring problem of overloading. As for the damaged motor, compressor, and fan motor, as well as the dirty condenser coils, a certified technician should look at them and suggest the best ways to repair or replace the malfunctioning parts.

The AC could switch off unexpectedly in the middle of a cooling cycle for any one of the reasons listed above. But the extra symptom, the thermostat going blank, adds an unwelcome twist to the plot. A common root of this failure is moisture backup in a clogged condensate line. When the moisture fills up the drain line, it gets diverted into a secondary pan. This pan has a float switch that cuts the power for the condenser, the thermostat, and the blower motor when the drained moisture reaches a certain level.

Algae and dirt pile up in the condensate line are the two guilty parties behind this snag. Before you call a contractor, locate the secondary drain pan which is usually fitted under the evaporator coil. If the pan is full of water, that will confirm the clogged condensate line diagnosis. Your technician will likely use compressed air to clear up the clogged line.