What Should You Do When Strange Noises Come from Your Air Conditioner?

A/C Makes Weird Noises

Do you have loud noises coming from your air conditioning unit? If so, you’re probably wondering what the sounds mean and why your air conditioner is making them in the first place. All sorts of system issues can produce strange noises when they malfunction – loose parts, high internal pressure inside the compressor, a refrigerant leak, loose fan belt, or electrical problem, for example.

Whether you hear buzzing, hissing, clicking noise, squealing, banging, or rattling, you’re not going crazy. Each noise is just a sign of air conditioner troubles. Jarboe’s Plumbing, Heating & Cooling explains what each common air conditioner sound could mean as well as what needs to be replaced or fixed when you hear it. Listen closely to your central air conditioner this season so you know when to call a professional for air conditioning repair services.

A Banging Noise

When your air conditioner produces a banging noise, you likely have loose parts somewhere within the indoor or outdoor unit. Inside, the blower fan may have loose fan blades that are hitting up against other components during operation. Outside, there may be loose parts within the compressor such as a broken piston pin or loose connector rod.

How to Fix this Sound

A banging noise can be resolved through repair services to fix or replace components in question. Loose fan blades affecting the indoor blower fan can often be adjusted to prevent banging sounds as the blades strike other components during a cooling cycle. Loose parts on the inside of a compressor typically mean the entire compressor should be replaced. This is in most cases a more affordable repair than attempting to access and switch out damaged components within the closed compressor.

A Clanking Noise

Your air conditioning may make a clanking noise with loose parts, too. However, a clanking noise may also indicate fans that are out of balance. The blower fan inside or the condenser fan outside can become unbalanced, causing the cooling system to operate inefficiently and risking damage to nearby parts.

How to Fix the Noise

If you have an air conditioner making clanking sounds, turn off the system and make a call for repair service. A technician is able to adjust fan blades and put them back into balance so the system uses less electrical power to operate and you don’t risk causing damage as fan blades spin out of whack during your cooling cycles.

A Clicking Noise

You’re probably familiar with the normal clicking noise that comes from your thermostat when it starts the air conditioner and shuts down a cycle. This is one quick click at the beginning and end of operation.

If a clicking noise persists throughout the cooling cycle, this sign points to a thermostat or electrical problem. A relay switch to a fan motor or capacitor to the compressor may be malfunctioning, or the thermostat may be going bad and is unable to properly signal the air conditioner for cycles.

How to Fix This Noise

Any electrical problem with your heating cooling equipment should be handled by a pro. There are many electrical components within an air conditioner, which we can diagnose correctly and fix right away. Should you suspect your thermostat is dying and making a repeated clicking noise, it helps to have a professional inspect the control to determine if there is a fix for the issue or if the thermostat needs to be replaced instead. Doing so could mean more years of service from your thermostat, allowing you to save money on unneeded repairs and replacements.

A Buzzing Noise

A buzzing noise from your home’s outdoor unit could be a sign of the following air conditioning malfunctions:

  • Malfunctioning condenser fan. The motor that runs the outdoor fan can suffer from electrical issues or be negatively impacted by internal debris, which both can cause a buzzing noise. Buzzing noises can also indicate the motor is wearing out and needs to be replaced.
  • Compressor malfunction. The compressor may make buzzing sounds when electrical issues are present. A faulty relay switch could send incorrect electrical amperage through to the component, producing sounds of buzzing.
  • Isolation feet damage. Inside the condenser unit, the compressor is installed on isolation feet made of rubber. If the feet are loose or damaged, the vibration of the compressor during operation can sound like buzzing.

When buzzing noises originate inside the home, a frozen air conditioner is likely to blame. Ice forms on the evaporator coils when the coils do not receive adequate heat. A frozen air conditioner usually results from low refrigerant due to a leak, poor air flow due to a dirty air filter, or other problems. Ice accumulation can be heavy if the drip pan and condensate drain line are clogged below, trapping more moisture inside the chamber.

How to Fix the Noise

When buzzing noises come from the outdoor unit, it’s best to have a professional perform repair service to replace compressor parts or the fan motor in the condenser.

If your evaporator coils are frozen, take these steps to thaw them and eliminate the buzzing noise:

  1. Switch the thermostat from COOL to OFF and give your air conditioner as much time as it needs to thaw out.
  2. Switch the fan setting from AUTO to ON so warm air will continuously cycle across the coils, helping to thaw ice.
  3. Inspect your system’s air filter. If it is dirty, replace the air filter with a fresh one. Running your air conditioner with a dirty air filter prevents the evaporator coils from receiving adequate air flow.
  4. After all ice has melted from the coils, turn the air conditioning system back on and allow the system to cycle. Should the system freeze over again, call a professional for repair service to find the source of the malfunction.

A Squealing Noise

A squealing noise from the outdoor compressor is the sign of a serious system issue. A high pitched squealing indicates high internal pressure inside the compressor. It is dangerous to operate your air conditioner when compressor pressure is too high. The squealing occurs right as a cooling cycle begins and the noise stops about 10 to 15 seconds after it begins.

Squealing sounds can also be caused by fan motor issues.

  • Dry bearings inside the motor cause metal to rub against metal, producing a squealing or grinding noise as the blower fan or condenser fan runs.
  • Older air conditioners may have a blower fan that is belt-driven, which means the fan and motor are connected by a fan belt. If the belt falls out of position, a squealing noise can occur during operation.

How to Fix This Noise

If you hear squealing sounds from inside the compressor, shut off your air conditioner right away and make a repair appointment as soon as possible. Keep the air conditioner turned off until professional repairs are completed.

Squealing due to dry bearings and a loose fan belt are issues typically resolved by a technician during your seasonal maintenance tune up. If your air conditioner has not received professional maintenance service yet this year, go ahead and schedule services now.

If you would like to tackle these issues yourself, follow these steps:

Lubricate fan motor bearings in the condenser

  1. Disconnect electrical power to the outdoor equipment
  2. Remove screws from the cover and lift off cover.
  3. Access the fan mounted below the cover or within the cage assembly below it. Turn the assembly over to access the fan motor.
  4. Find the motor oil ports and remove coverings.
  5. Insert oil into each port until filled, using a rag or cloth to wipe away any excess.
  6. Replace plugs and reposition cage assembly and/or condenser cover.
  7. Tighten screws to secure condenser cover and restore power.

Lubricate blower motor bearings and reposition fan belt

  1. Cut electrical supply to indoor unit.
  2. Take off the access panel to the blower chamber.
  3. Unscrew circuit board and move aside.
  4. Loosen and remove mounting bolts then slide the blower assembly out of the chamber.
  5. Remove oil port plugs and add 2 to 3 drops of oil per port, then replace plugs.
  6. Reposition the fan belt onto the two pulleys of the blower motor assembly. Press on the belt to test tension and adjust tightness if deflection is 3/4-inch or more.
  7. Loosen nuts on the sides of the motor. Slide the motor back to tighten the fan belt.
  8. Once taut, tighten the nuts and recheck fan belt tension.
  9. Replace the circuit board and access panel.
  10. Restore electrical power to the indoor unit.

Hissing Noises

Hissing sounds your air conditioner is making indicate a refrigerant leak. You may notice the hissing sound comes from somewhere along the refrigerant piping or could be within the unit, likely caused by a bad expansion valve or other component. You may also notice a bubbling noise at the location of a leak along the copper lines running between indoor and outdoor system equipment.

A hissing sound could also be a precursor to the squealing noise that results when there is high internal pressure within the compressor. Hissing eventually turns to squealing sounds, warning you of immediate danger.

How to Fix the Noise

Whenever you hear a hissing sound that you suspect is from a refrigerant leak, call a professional for repair services. Only certified HVAC professionals are capable of safely handling refrigerant and making repairs to refrigerant piping. Once leaks are repaired, the air conditioner is recharged with refrigerant so the system has enough coolant for efficient cooling. If your older air conditioner uses R-22 Freon refrigerant, make sure possible refrigerant leaks are addressed right away as Freon is damaging to the ozone layer.

Stop Air Conditioner Noises Today

If you have an air conditioner making disruptive sounds in your Louisville area home, don’t wait to call Jarboe’s for air conditioner repair services. Our technicians find the source of the buzzing, banging, clicking, or clanking you hear and make fast repairs so you can enjoy peaceful, efficient cooling power once more.

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