Outdoor AC units can be fairly loud. When your air conditioning is running, you’ll always be able to hear both the compressor and the condenser fan running whenever you’re anywhere near the unit. This noise is normal and not something you usually need to worry about. Hearing a buzzing noise or other unusual sounds coming from your AC unit is a different story, as this can potentially be a sign of a serious problem that could lead to the unit breaking down or getting damaged. We’ll look at the most common causes of buzzing and other unusual noises and why this type of issue isn’t something to ignore.
Buzzing Noises
A buzzing sound is usually a sign of an electrical problem, such as a loose wire, failing capacitor or failing contactor relay switch. A loose wire or electrical connection is a serious concern since it can short-circuit the appliance. A short circuit can cause a massive spike in power that leads to wires melting or the unit catching on fire. These risks are the main reason why you should immediately call for a professional inspection if your AC starts buzzing.
The contactor relay switch is the link between the thermostat and the outdoor condenser unit. When the thermostat senses that the AC system needs to run, it sends an electrical signal to the switch. The switch then signals the compressor and condenser fan motors to start running. The switch usually produces a loud buzzing sound that indicates it’s starting to fail and will likely give out soon, meaning you won’t be able to run your air conditioning until you have the switch replaced.
Air conditioners have both a start capacitor and a run capacitor, which are like large batteries that supply additional power to the compressor motor and the condenser fan motor. The start capacitor supplies the extra surge of power that the motors need to power up, while the power from the run capacitor ensures the motors run smoothly and don’t draw excess electricity. A failed start capacitor will usually prevent the outdoor unit from turning on. In this case, you’ll usually hear the motors making a humming sound. You may also hear a repeated clicking sound coming from the unit. Your AC may still work if the run capacitor fails, but you’ll often experience issues with it frequently tripping the breaker or shutting off intermittently.
Squealing or Screeching
Squealing or screeching sounds are almost always a sign of a worn-out belt or worn-out bearings. Some older AC units have a belt that drives the compressor motor and another that drives the condenser fan motor, but the majority of appliances in use nowadays have bearing-driven motors. If the belt or bearings that drive either motor are starting to wear out and making a loud squealing or screeching sound, you need to call for air conditioning repair right away. If you wait too long to replace the belt or bearings, the motor will eventually start overheating and potentially seizing up and burning out. This is especially a concern with the compressor motor, as replacing the motor can cost almost as much as buying a new air conditioner.
Humming
A humming sound when the outdoor unit isn’t running is usually a sign of a failed start capacitor or a failed compressor. If you hear humming when the unit is running, you should check to see if the condenser fan is spinning. In some cases, there may be an object like a stick jamming the blades and preventing the fan from spinning. This typically results in the fan motor making a loud humming sound as it tries to spin the blades. If the motor is humming and nothing is obstructing the blades, but the fan isn’t spinning, it’s a good indication that the motor is worn out and needs replacement.
Request AC Repair From Reddi Services
When air conditioning problems arise, you can always count on the experts at Reddi Services for help. We offer same-day and 24/7 emergency AC repair and will work to quickly fix the problem. Our AC maintenance services can also help prevent most common problems so that you can enjoy efficient cooling performance throughout the summer.
We serve residential and commercial customers throughout the Phoenix, AZ metro area and are ready to assist with all your comfort needs.
To schedule an inspection and receive a free AC repair or maintenance estimate, contact our team at Reddi Services today. We service Phoenix, AZ, and Kansas City.
