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5 Signs That Indicate Your AC Fan Motor is Bad

by The Cooling Company, on Sep 16, 2019 10:06:09 AM

If you’re like most homeowners, you probably don’t understand the inner workings of your air conditioner. Nor do you wish to. All you care about is that it continues to produce that refreshing cold air you rely on to keep your Las Vegas home cool.

If, however, you’re mechanically-inclined and interested in learning some basics about how an AC functions, then keep reading. We’re going to discuss an important part of your AC unit — the fan motor. Without a functioning blower motor, your AC is rendered useless. You’ll either suffer no air or weak airflow. 

Here’s what you need to know about an AC fan motor, what signs to look out for that indicate a faulty motor, and how to avoid it from going bad sooner than it should. image-19

What is an AC Fan Motor?

The fan motor is a fairly uncomplicated yet vital part of an air conditioner. It’s the part of the unit that pumps air through the system. Without that circulation of air, your AC won't cool your home. 

Because the fan motor is one of the hardest working parts on an air conditioner, it is subjected to a lot of wear and tear that can lead to frequent repairs or replacement. Once the fan motor breaks down, the AC will stop blowing cold air and that’s something you don’t want on a hot summer’s day.

5 Signs That Indicate a Failing AC Fan Motor

When your air conditioner suddenly breaks down, it’s difficult to know where to start in identifying the problem. Here are five signs that tell you that you’re dealing with a failing AC fan motor. 

1.  The fan won’t start even though the AC is on

When the fan doesn’t start even though the AC is turned on, it can be a clear sign that there’s a fault with the motor. When the AC runs without the fan circulating air, it can eventually lead to the evaporator coils freezing over. Once this happens, your air conditioning unit is at risk of suffering more serious damage. Turn the AC off and call an HVAC technician. 

2.  The fan continues to run, even when shutting off the AC

The opposite problem can also occur, i.e. the fan continues to run even after switching off the air conditioner. In some cases, this is caused by a malfunctioning thermostat. Replacing the thermostat will have it up and running again. 

If the thermostat isn’t the issue, the most likely problem is a stuck relay switch. Relays are what open and close the electrical circuit in an air conditioner. When a relay becomes stuck, the circuit remains closed. As a result, electric power to the fan motor doesn’t stop and the fan continues to run. 

3.  The fan is on but rotating very slowly

Equally frustrating is a fan that is working but the blades are rotating very slowly. A slow-turning fan will generate weak airflow. If your AC offers different fan settings, check if it is set at low speed. If that isn’t the case, it could mean the motor bearings need to be oiled or that the capacitor is failing.

4.  The fan runs intermittently

When the fan runs intermittently, it could be one of two problems. The motor could be overheating which causes it to cut out. Alternatively, a loose wire or connection or a short in the motor windings could be the culprit. 

Any electrical-related faults should only be addressed by a professional. Never attempt to work on a fan motor when you suspect an electrical issue. This can be dangerous and is a job best left to a trained HVAC technician or electrician.

5.  There’s a rattling or buzzing noise coming from the condenser unit when the fan is turned on

There is more than one possible cause for a noisy air conditioner. If you hear a loud rattling noise, it could be a minor issue like loose stones or debris that’s caught in the condensing unit. A rattling noise can also be caused by loose or unbalanced fan blades striking the side of the fan housing unit. 

If you don’t see anything stuck in the condensing unit and the fan blades are turning freely and smoothly, then the likely cause is the fan motor. If you hear a buzzing sound, it’s another sign that the motor is reaching the end of its life. 

Steps You Can Take To Identify a Problem With The AC Fan

If the AC fan motor is bad or the capacitor is faulty, you should always contact an expert HVAC technician to repair or replace parts. However, there are some preliminary steps you can take to rule out other possible causes for your AC not working and confirm that the problem is, indeed, with the AC fan motor. 

Check for a tripped circuit breaker

Sometimes the reason an air conditioner is not working is as simple as a tripped breaker. The first step is to check the circuit breaker. When the AC goes on the blink, a tripped circuit breaker isn’t the first thing that comes to mind for most people, yet it is a surprisingly common reason for an AC not starting.

Check the air filter

When was the last time you replaced the AC unit's air filter? Many homeowners neglect this basic maintenance task. A clogged air filter reduces airflow. If the air filter is clogged, replacing it with a new one should get the air flowing freely and strongly again. 

Check the outdoor unit

If you’ve ruled out the above problems, it’s time to head outside to the condensing unit. If your AC has stopped blowing air, has weak airflow, or you hear unusual noises, do a quick inspection of the fan motor. The motor is located in the condenser unit. Listen for a humming sound that tells you the AC compressor is functioning. Next, look through the vents at the top of the unit to see the fan. Are the fan blades turning? If the compressor is working but the fan blades are not spinning, the motor is faulty. That’s your cue to turn the system off and call the pros to repair the AC fan motor. 

What Your HVAC Technician Will Do

Replacing an HVAC motor is a job that can be done quickly once the problem is identified. With the information you have provided, the HVAC technician will take the following steps to confirm the problem.

Conduct a Visual Inspection

A trained technician can quickly spot certain problems on a visual inspection of the condenser unit. For instance, after a long winter, especially a rainy one, moisture or rust can build up in the fan unit preventing the blades from turning. 

Check the Condenser Unit’s Temperature

Condenser fan motors all have a temperature stipulated by the AC manufacturer at which it can operate safely and problem-free. In most cases, the ideal temperature is around 150 degrees Fahrenheit. If you are near the condenser unit and it feels hotter than usual, it indicates that the fan motor may be overheating. HVAC technicians are equipped with an infrared temperature gun that can read the unit’s temperature without having to touch the hot surface.

Attempt to Manually Kick-start The Motor

During winter your AC lies dormant. This inactivity can lead to a build-up of dirt or rust that makes it difficult for the fan blades to start rotating again when you switch on the AC at the start of summer. The technician may try to manually kickstart it. 

Check The Capacitor

The start capacitor is a cylindrical component that supplies the electric charge that starts the condenser fan motor. It plays a vital role in starting up your AC. Without that boost of power, the fan motor is unable to start. That's why when the capacitor stops working, so too does the air conditioner. 

Never try to remove or fix the capacitor yourself. If the AC is still switched on, the electricity that runs through the capacitor can result in a serious electric shock, injury, or even death. Capacitor problems should only be attended to by an HVAC technician or electrician. 

Inspect the Electrical Wiring

If none of these are the problem, the technician will check the condition of the electrical wiring and the windings to see if it is open or has a short. If switching on the AC frequently causes the circuit breaker to trip, it’s likely due to a short in the windings. The technician will do a resistance check by measuring the ohms. If the resistance is zero, it means there’s a short. If there is an infinite reading, it means there’s an open winding. In both cases, the motor will need replacing.

How To Prolong The Life of Your AC’s Fan Motor

As mentioned previously, the fan motor is one of the hardest working components in your air conditioner and wear and tear will eventually take its toll. However, you can prevent it from burning out sooner than intended with regular HVAC maintenance

One common reason an AC fan motor burns out is due to dirt building up around the fan motor. Dirt can creep into the holes of the motor, causing more friction for the inner workings which stresses the motor and causes overheating. Regular dusting in and around the motor hole can prevent this. This easy maintenance task helps prolong the lifespan of the fan motor and can prevent more serious AC problems. 

If you’re not the most diligent person when it comes to HVAC maintenance, then the best way to ensure regular maintenance is to sign up for a maintenance plan with your HVAC company. Most maintenance plans include biannual HVAC tune-ups. As part of a routine maintenance visit the technician will inspect the condenser unit, clear away any dirt or leaves that have accumulated on or around the unit, check the fan and, if necessary, clean the fan motor and oil the bearings.

Who To Call In Las Vegas When Your AC Needs Repairs

Being without air conditioning during summer is never pleasant. If your air conditioner needs repairs and you live in Downtown Las Vegas or any of the surrounding areas including Henderson, Paradise, and North Las Vegas, call The Cooling Company at 702-567-0707. Our trained technicians will have your AC up and running again in no time. 

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