Although you should expect your air conditioner to make a moderate amount of noise according to its size and function, it's also true that uncharacteristically loud sounds may indicate a problem. Before you involve a repair professional, there are several ways you can try to eliminate the problem on your own. Here are three steps to troubleshooting your noisy air conditioning unit.

1. Fan blade

The first thing to look for is debris obstructing the fan blade. Leaves and small twigs can fall in and rattle around, especially if you have trees or shrubs near your house. Turn the machine off before opening it, then check for any vegetable matter or other foreign objects in the fan and clear them out. In winter, this could even include chunks of ice. After troubleshooting the fan, turn the air conditioner back on and listen for the sound you heard before. If it's still there, proceed to the next step.

2. Coil fins

These fins may become dirty over time, or they can be bent from incautious handling. Either of these scenarios can produce an odd sound. Try cleaning the fins gently with a vacuum cleaner attachment and check for bent fins while you're at it. Bent fins can be gingerly bent back into shape, a process which requires a special tool called a fin comb. The fin comb is relatively inexpensive, so you can perform this technique yourself.

3. Loose parts

A screwdriver could be your best friend in this situation. Some vibrating sounds are caused by loose parts rattling together because screws have worked loose and the parts aren't being held securely in place. While the unit is switched off, go over it with a screwdriver and tighten any screws you find. Don't forget to inspect and tighten the fan, which can make rattling sounds even without any precipitating debris when not screwed down properly. If you've tightened all the screws you can find and the unit still makes an abnormal rattling sound, there may be a problem with the compressor. Compressor motors wear out over time and tend to make louder sounds as they age.

These three troubleshooting steps will help you eliminate many of the causes of strange sounds in your air conditioner. After going through all three steps, you should turn your air conditioner back on and check to see if the sound is gone. If it persists, you may want to call a repair professional at Armstrong Air, Ref.& Heating - David Armstrong Services, LLC, who will diagnose the issue and let you know whether there is any danger to your unit's functionality.