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A strange noise can be the first sign that an HVAC system has a faulty part. Often, the noise emanates from the compressor – an HVAC system’s central component. When it heats, a compressor raises the temperature of gas by reducing its volume. When it cools, it performs the same process, but a fan cools the gas until it condenses on the condenser coil. When a compressor has problems during either of these processes, it often makes one or more of the following sounds:

Banging or Clanging Sound

A compressor that makes a banging or clanking sound may have a loose internal part. Loose connecting rods, piston pins, and crankshafts are common examples of loose parts that cause clanking or banging sounds. When a compressor is sealed, repairing loose internal parts is not an option. It must be replaced.

Hissing or Bubbling Sound

A hissing or bubbling sound often results from a leak in the refrigerant line that runs to the air distribution unit. Large leaks usually produce a hissing sound, while small ones often make a bubbling sound at the refrigerant lines. Leaky refrigerant lines are typically replaced and not repaired. Replacing them promptly prevents the loss of cool air.

Screaming or Hissing Sound

Loud hissing that could be described as screaming may result from abnormal pressure inside a compressor, and signals that power to the unit should be discontinued immediately. The sound may also result from leaky internal valves – a condition that causes the component to operate inefficiently. In either case, a new HVAC compressor must be installed.

Buzzing or Clicking Sound

A compressor that makes a buzzing or clicking sound may indicate a faulty thermostat, which could cause relays to click on and off repeatedly. It may also indicate faulty relay lines. In some instances, high frequency clicking creates a buzzing noise. Replacing or repairing a faulty thermostat or faulty relays is the solution.

Humming Sound

A compressor that makes a humming sound may be low on oil. If it is not hermetically sealed, evidence of oil leakage may be seen, or a sight glass may indicate a low oil level. If a compressor is hermetically sealed, which is the case with most residential compressors; it must be inspected for low oil by an HVAC service.

Rumbling or Rattling Sound

A rumbling or rattling sound may result from loose hardware around the compressor. Shipping bolts, tubes, and springs are examples of hardware that can become loose. Loose hardware should be repaired by an HVAC service to prevent injuries due to shock or moving parts.

Is Your Compressor Making Strange Noises?

If your compressor is making a strange noise, have it inspected as soon as possible. The noise may mean nothing, but it could also signify that your compressor needs repair or replacement. Bardi Heating and Air Conditioning can make this determination in a single visit, and explain why repair or replacement is the best option. For the best in air conditioning replacement and repair, call Bardi today.