How To Troubleshoot Your Central Air

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air conditioner and brick wall

When the sun is blazing outside and it’s getting stuffy inside, central air conditioning starts to feel less like a luxury and more like a necessity. It’s possible to survive without AC, but when it’s on the fritz, you still want to fix it as soon as possible. Serious damage to the unit requires a professional for repairs, but you can do a lot of minor fixes by yourself. Here’s where to start.

Thermostat Function

You’ll want to start your troubleshooting at the thermostat rather than the air conditioner unit itself. Double-check that the thermostat is set to “cool” and that its temperature is set lower than the current room temperature. Human error is more likely than mechanical failure in many cases of home maintenance.

The 5 Degree Rule

Air conditioners, especially older units, don’t measure temperatures entirely accurately. If you experience any interruption in function, the first step after checking that the thermostat is functioning is to lower the thermostat by five degrees. This will mitigate any inaccuracies in the machine’s temperature gauge, and then you can adjust it back to the desired temperature.

Breaker Checks

Another likely culprit of malfunction is a lack of power to the unit. If the outside fan of the central air unit isn’t running, this could indicate that it isn’t receiving electricity. Find out which breaker switch in your home’s power box connects to the air conditioner and check to make sure it hasn’t been switched off. If the unit doesn’t work after a breaker check, there’s likely a deeper problem with the internal electrical system and you should call a repair technician.

Frozen Lines

Occasionally, some of the AC unit’s refrigerant lines can freeze during periods of high activity. If you notice ice on any of the lines or water pooling around the unit, it needs time to warm up. Simply shut off the outer portion of the unit but let the blower continue to run. This will bring enough warm air into the lines to melt the ice and return normal function to the system. If freezing persists, there may be a bigger problem with the refrigerant system that requires a professional to fix.

Cleaning Filters and Condenser

Air conditioners pull in a lot of air and that means accumulating particulate matter. If you start to feel your AC under-performing, the problem could be as simple as a dirty filter or condenser. You can clean these components yourself, but be careful not to damage these items by scrubbing too vigorously and avoid using too much soap, as that may enter the air you breathe. Plants can also enter these components, so keep the area around the AC unit weeded and clear.

Don’t rule out professional intervention

As with any delicate piece of machinery, DIY troubleshooting for your air conditioner unit can only go so far. Unless you have experience building or repairing air conditioner units, leave major repairs and parts replacements to professionals. The service fees are a small investment compared to replacing an entire AC unit because of a botched repair job.


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