Heat pump going bump in the night? The experienced professionals at H & H Heating & Air Conditioning have the information you need to help you distinguish normal sounds from dangerous system issues.
If You Hear these Normal Heat Pump Noises, All is Well with Your System
These noises are typically mild and of the lower decibel variety, including:
Whooshes Heat pumps often make whooshing sounds during defrost mode. This can last several seconds and is usually followed by a slightly louder compressor sound. These sounds may be louder in the winter when your heat pump works hardest.
Rattles & Vibrations
These sounds, which can be similar to an off-balance washing machine or back-peddling flutter, are normal at startup and shutdown.
Clicks & Taps
Clicking and tapping noises are normal at startup and shutdown.
Humming, Buzzing Sounds
A slight buzzing from your system, even when it’s not in operation, is normal in most cases. This is typically from the reversing of the valve solenoid coil, a low-voltage valve that is louder in certain systems.
A high-pitched squeal at startup is typically normal.
Metal on Metal
In cold weather, this may be from your fan blades hitting chunks of ice. It can also result from blades hitting loose wires or other components. When this occurs, turn off your system immediately to avoid damage to fan blades and other components, as well as to avoid overworking the motor.
Rattling & Vibrations
If there aren’t a couple of loose screws in the cover panel, ratting and vibrations that worsen over time indicate loose hardware/parts in need of adjustment. They also occur if refrigerant piping is strapped too tightly, or emanates from unsecured ductwork. Some air conditioners are also noisier than others, with this scenario worsening over time until replacement.
Frayed or loose fan belts often clank.
Popcorn Popping or Tumbling Rock Sounds
This strange sound typically occurs when the compressor receives liquid refrigerant. There are a number of causes. All should be addressed immediately.
Gurgles point to low refrigerant levels, which can severely affect performance.
A precursor to shrieking, grinding noises indicate dirty components or the need for lubrication.
Unbearably loud shrieking noises usually indicate a faulty compressor under high pressure. Shut down your system immediately. This is a dangerous situation, indicating the need for 24-hour air conditioning service. Dirty motor bearings can also be unbearably loud, indicating a motor in need of replacement.
Hissing typically indicates a massive refrigerant leak and a system that will likely be out of commission in the immediate future.
Humming, Buzzing Sounds When System is Inoperable
A humming, buzzing noise when your system will not run could point to a stuck relay or contact, faulty capacitor, or motor issues.
A high-pitched squeal that begins without notice could indicate the heat pump motor is going bad.