How To Correct Noise Problems In Your Air Conditioning Outdoor Unit Fan


A squeaky, whining or rattling fan in your air conditioner's outdoor unit can be worrisome, but the noise is often due to relatively simple causes. Below is a step-by-step guide to correcting the common causes of a noisy fan:

Tools and materials needed

  • Nut driver set

  • Work gloves

  • All-purpose spray cleaner

  • Lightweight spray lubricant

  • Paper towels

  • Stiff-bristled plastic brush

  • Flashlight

Step-by-step procedure

1. Disconnect the power to the unit - Before performing any work on your outdoor unit, you must disconnect the power to prevent a possibly severe electrical shock. Most air conditioner units are connected to an electrical box mounted on the closest exterior wall; this box contains a pull-out switch that must be removed to disconnect power. Pull on the handle and remove it from the box, but be sure to place the handle where it will be easily found when you need to reconnect power.

2. Remove the fan grille - The fan blades are covered by a heavy wire grille that is attached to the outdoor unit housing. Find a matching nut driver size and remove the sheet metal screws that hold the protective grille in place. Carefully pull the grille away from the fan and set it aside.

3. Inspect the fan blades for dirt and debris - The next step is to ensure the fan blades are not dirty or do not contain debris. Begin by slowly rotating the fan blades by hand and examining each blade for signs of dirt or other debris. You may need a flashlight to see beneath the blades if the lighting is poor.

It is not uncommon for fan blades to be caked with dried mud, especially if the outdoor unit is on the ground or near bare soil. In addition, be on the lookout for other debris such as insect nests, small animal carcasses, trash, or plant matter. The presence of any of these aforementioned items can cause your fan blades to be unbalanced, and that results in excessive noise due to the strain placed upon the fan motor and its bearings. In addition, trapped debris may be rubbing against the other components of the unit, which also causes noise.

4. Clean the fan blades - If the blades are dirty or debris-laden, this is an ideal time to clean them. Begin by spraying the blades with an all-purpose spray cleaner and allowing the cleaner to soak for several minutes to loosen stubborn materials. Once the blades have soaked, use a stiff-bristled plastic brush to scrape away the dirt or debris. Wipe the fan blades clean with paper towels, then lightly coat the surfaces of the blades with a spray lubricant to provide protection against corrosion and to help prevent debris from sticking to them in the future.

5. Inspect the fan blades for damage - Once you have cleaned the fan blades, it will be easier to examine them for signs of damage. Look for dents, cuts in the metal, or warped blades that are not aligned with the others. Damage such as this can be caused by objects thrown by lawnmowers, toys inserted into the fan by children, and even natural causes such as falling tree limbs. Any such damage can cause the blades to be unbalanced in much the same way as dirt or debris, thus creating excessive noise.

6. Repair damaged fan blades, if possible - If you spot signs of damage to the blades, then you can repair some of the problems yourself. For fan blades that are bent out of position, grasp them with gloved hands and firmly, but slowly, bend the blades just a small amount at a time to restore their shape. Keep checking the blades as you bend them back into position to avoid bending them too much in the opposite direction. Excessive amounts of bending cause metal fatigue, which can cause the blades to tear during operation. This could cause serious damage to your unit should the blade pieces strike other nearby components such as the compressor, fan motor or condenser coils.

If your fan blades are cut or otherwise compromised with structural damage, then you will need to contact a qualified professional to replace the fan blades. Be sure not to operate an air conditioner with damaged or missing blades on the fans, as it can become dangerously unbalanced and destroy your compressor or condenser coils.

7. Restore power and test the system - Once you have performed your cleaning, and inspection and repair of blades, if needed, then you need to replace the grille. Next, re-insert the pull-out handle into the socket inside the electrical box to restore power. Turn the system on and listen to evaluate whether or not your cleaning and/or repair procedures were successful. If not, then other problems are likely causing your noise, and it will need to be addressed by a professional technician from a company like Elite Heating, Cooling and Plumbing.


15 December 2015

Shopping For A New HVAC System

After my sister moved into my house with me, she started complaining about the temperature. I had never really thought about it before, or maybe I was just used to it, but my house was pretty cold. She told me that she didn't think the furnace was working properly, so I started checking things out on my own. Sure enough, my furnace seemed to be having some serious problems. I started looking for a replacement, and I was able to find a great furnace for much less than what I initially thought I would need to spend. I wanted to make this blog for anyone out there who might need to shop for a new HVAC system. Check out these great articles for information you might need.