Understanding and Maintaining Your Central Air Conditioner

A high-efficiency, modern AC unit in front of a brick wall.

Most modern people cannot live without their central air conditioners. It's what they look forward to most when they head home after a long, hot day of work in the middle of summer. For the most part, central air conditioning systems are trouble-free and require only a minimal amount of routine maintenance.

How Your Modern Central Air Conditioner Works

Central air conditioners can seem complex, but they work in a similar way as the refrigerator in your kitchen. The outside components include an electrical disconnect switch, a condenser coil, a fan and motor, and a compressor. Inside, you will have other elements such as a furnace with a blower, a condensate drain and pump, a condensate tray, an evaporator coil, and plenum and ductwork.

Refrigerant circulates between the outside condenser coils and the inside evaporator coils. While the refrigerant is inside, it absorbs heat from the room, then travels to the compressor. The refrigerant is compressed by way of heat, and then leaves to enter the condenser where it gets condensed as the heat is removed. The cold refrigerant then gets sent back to the evaporator coils.

While this is happening, the blower forces air through the cooled coils into the rest of the house by way of the ductwork. As the heat leaves the air, it's forced to give up its moisture. The moisture is called "condensate." The condensate gathers in a pan and is eventually removed by the pump, which sends it to a drain in your home.

We also have the luxury in this modern age of being able to control exactly when, and for how long, our AC will run with the use of programmable thermostats. They allow our system to be as efficient as possible because they can turn the system off in the middle of the day when no one's home and then turn it on right before you return home. Not only is it convenient but it saves on the electric bill as well.

How to Maintain It

Most central air conditioning systems share the same ductwork and blower as the furnace. That means they also share the same filter. You should check your filter at least three times a year because they can build up a lot of dirt in a quick amount of time. A clogged filter can cause your system to run poorly and increase your utility bills. Families with pets should actually change their filters even more often.

Here's a list of some other central air conditioner problems and their remedies.

1. AC Doesn't Turn On

The central air should be on a dedicated circuit. Check the electrical panel to make sure the breaker didn't trip. If that isn't the problem, check the disconnect box near the compressor to see if it was turned off. Also look at the furnace power switch itself to make sure it has not been flipped off. Lastly, you can look at the access panel near the compressor. On hot days the compressor may shut down, requiring you to press the reset button.

2. Air Runs But Doesn't Cool

Check the filter first, as it may be clogged and restricting air flow. Some other things to check include the condenser cover outside and the thermostat. Clean any debris on or around the condenser cover and make sure the thermostat is set to cool and not heat. For non-programmable thermostats, this is a common problem, especially in the early spring.

3. It Looks Like There's a Leak

Inspect your condensate pump and make sure there are no leaks in the drain hose. Also check the outlet that the condensate pump is plugged into for power. Finally, as before, check your filter. Clogged filters can cause the formation of ice in the tube.

These are just a few of the potential problems you may experience with your central air conditioner. Obviously these are only some of the most common and easy to fix, but the most important thing to always remember is to check and change your filter on a routine basis. It can save you a lot of trouble down the road.

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