If you live in an area where the oppressive heat of summer makes living without a central air conditioner unthinkable, you may worry that it could break down without any warning. If so, look for the following subtle signs that your air conditioning unit may need repairs.

You Hear A Low Buzzing While It's Running

While your air conditioner is running, listen carefully for a low buzzing sound coming from the unit. This will be different than the normal whooshing noise made by the blower. Instead, it may sound like a small swarm of bees has taken up residence inside your air conditioner.

This sound could be caused by two different things. One explanation is that the blower fan could be loose, causing it to vibrate as it turns. To see if this is the culprit, turn off the unit, and remove the side access panel. Then, find the center bolt on the fan, and tighten it with an adjustable crescent wrench until the bolt is hand tight. Turn the unit back on, and listen carefully. If you do not hear the noise, the fan was the issue. 

If you still hear the buzzing sound, this could be an indication that the motor is malfunctioning. In this case, you will need to have an HVAC professional look at the unit.

You Smell An Acrid, Smoky Odor When The Unit Turns On

The next sign you want to watch out for is an acrid, smoky smell whenever the unit turns, especially if no one smokes in your household. This odor is different than the musty smell created by dust when an air conditioner is first turned on after you haven't used it for a while, such as over the winter months. The smoky odor may also have a slight burning smell to it.  

If you start noticing this smell, this could be a sign that the wires inside the motor are starting to fray, causing short arcs of electricity to strike the casing. When this is the case, you should call an air conditioning repair service as soon as possible, since the condition may worsen quickly, causing the motor to short out and burn up completely.

If you notice any of the above signs, your air conditioner may be on the verge of breaking down. If so, contact an air conditioning repair service to discuss your concerns and possibly schedule an appointment for an inspection.