How to Fix a Loud, Noisy Heat Pump Unit

heat pump troubleshooting

How to Fix a Loud, Noisy Heat Pump Unit

(Last Updated On: May 2, 2017)

Is your heat pump making loud, discomforting sounds? If your heat pump has suddenly become noisy, you may suspect that it’s about to have a breakdown. Noisy heat pumps are more common in the winter, and loud noises are often due to the valves shifting to put the unit into defrost mode. While a noisy heat pump could be simply that — noisy — it may also be cause for concern. Here’s how to know the difference, and what to do if your heat pump’s loud noises are more than just a winter quirk.

Your Heat Pump is Louder Than Usual

If your heat pump makes a swooshing sound, and then runs louder than normal for a time, it’s likely the function described above: the heat pump going into defrost mode. The swooshing noise is caused by the valves shifting, and the continued loud operational noises are often caused by the compressor, but it’s typically not a reason for concern.

Loud Noises During Shut Down or Startup

Heat pump units can make some strange sounds while starting up or powering down, which can be somewhat alarming if you’re not accustomed to these sounds. For instance, a heat pump with a Scroll-type compressor can make a few unusual sounds involving clicking and tapping when shutting down. When starting up, they can make loud, rickety noises that sound like the whole unit is bouncing back and forth.

These noises are typical, but if you’re used the sounds your heat pump makes, and it suddenly begins to make some previously-unheard noises, it’s a good idea to investigate to be sure something’s not amiss.

Loud, Metal-to-Metal Sounds

Sometimes, a heat pump may make loud noises that sound like metal hitting metal inside the unit. You should turn the unit off immediately and inspect the fan. These types of sounds are often the result of the fan blades hitting something that has ended up inside the unit, such as a chunk of ice or another component.

If this is the issue and the unit is allowed to continue running as-is, you could end up with a ruined fan — or even the motor, both of which would require the help of a professional HVAC technician to repair or replace the damaged component. Even if the contact doesn’t damage the fan or motor, the fan blades could damage whatever they’re hitting. For something like tubing, you could end up with a split tube that leaks refrigerant. In other words, there are all kinds of potential damages that can occur when your heat pump’s fan is hitting something else inside the unit, so turn it off and address the issue immediately before you end up facing a much more expensive repair.

Your Heat Pump is Making Rattling or Vibration-Like Noises

If your heat pump sounds like it’s vibrating, there are several potential problems, some of which are an easier fix than others. You can try placing rubber pads under the unit to absorb vibrations and reduce the noise. You should also check to determine whether the piping for the refrigerant is strapped too tightly. For rattling sounds, check to make sure the cover panels are screwed tightly in place, and tighten them if needed. If this doesn’t solve the problem, it might be caused by loose parts in the air handler or rattling ductwork.

Alternatively, you may simply have a vibrating or rattling unit that functions that way, in which case, it’s either something you’ll need to get used to, or you may consider replacing the unit if you have the budget.

Your Heat Pump Makes Buzzing, Grinding or Gurgling Sounds

Other common noises include buzzing sounds, which are typically caused by internal components such as contactors or coils, or gurgling noises, often caused by low refrigerant charge. Heat pumps with a dirty motor bearings can even make a noise that you might describe as shrieking, and this usually indicates a motor on its way to burning out, meaning a replacement will be in order. If your heat pump is making any of these sounds, you should contact a professional HVAC technician to examine your unit, identify the source of the problem, and recommend the best repair option.

Most homeowners don’t have the experience required to safely work with the inner workings of a heat pump unit, so seeking professional expertise is the safest choice. It can be difficult to correctly determine if there’s a specific malfunctioning component or if your heat pump unit is simply getting older and beginning to show its age. It’s not uncommon for heat pumps to become noisier later in their lifespan. If that’s the case, replacing your unit is usually your only option, but your HVAC professional will talk to you about your home heating requirements and make recommendations for the best models to meet your home’s requirements and your budget.

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