Why Is The Commercial HVAC System Making Strange Noises?

Commercial HVAC units are designed to run 24/7 with optimum efficiency and effectiveness. These units are usually installed in commercial buildings that need to be kept cool throughout the summer season. Considering the workload they experience, it is common for them to make strange noises sometimes. Instead of panicking, you should be familiar with such sounds and troubleshooting tips so that you know when to the issue is severe and you need to call in commercial AC repair services. Let’s take a look at the types of strange noises commercial HVAC units make.

Banging Noises

One of the most common unusual noises made by commercial HVAC systems is banging noises. If that is the case with your unit as well, it means there is most likely a problem with the compressor. The compressor is the most important component inside an HVAC system.

As the term suggests, the compressor creates pressure that changes the state of the refrigerant. With time, the bearings inside the compressor wear out and will produce strange noises. This is because the components inside the compressor might break and hit the external frame.

So, you will need to remove the compressor for repairs. Furthermore, if the HVAC system happens to be old, it will be wise to replace the entire unit instead of just going for the compressor. This is because your HVAC unit is already old and you might not be able to find the replacement parts for it. Moreover, a compressor is one of the most expensive parts of an air conditioner so replace the whole system if it’s old. New HVAC installation will cost you, but it will be a good investment.

Plus, you cannot remove and repair the compressor on your own. You must consult an expert who will guide you better.

Screeching Sounds

Screeching sounds are another major concern for the users of commercial HVAC units. Mostly, the culprit is a malfunctioning fan motor in the outdoor condenser unit which is placed at the rooftop of commercial buildings. The purpose of this fan is to remove the heat produced during the cooling process.

Similar to the compressor, the fan motor also contains bearings. If your HVAC system has suddenly begun making strange noises, it means the bearings inside the fan motor are gone. It might also be an indication that your fan motor is broken. Although, it is rare but can happen due to extreme weather conditions.

To rectify the screeching issue, you should consult an expert. You may or may not have to replace the entire fan motor. However, if it’s just the bearings that need to be replaced, you will be able to get the unit running back to normal in no time.

Humming Noises

If you hear a loud humming noise coming from your commercial HVAC unit, it’s usually a bad contactor relay switch. It starts the outdoor condenser unit when given a signal from the thermostat. Unfortunately, you will not be able to run the air conditioner as the sound will gradually become louder.

If that is the case, you should consult an expert immediately. It is most often that commercial business owners tend to ignore such noises coming from the HVAC systems. They expect them to go away on their own. This could create further problems in your HVAC system due to which you will have to pay for costly repairs.

That said, as soon as you hear humming noises coming from the HVAC system, immediately shut it down and consult an expert for commercial air conditioning repair Ronkonkoma.

Buzzing Sounds

Your commercial HVAC system making a buzzing sound is another serious problem. This sound might indicate loose fan blades in the outdoor unit. However, this might be a result of age or some external factor. For instance, extreme rain, snow, or thunderstorms can cause dead leaves, branches, and shrubs to come in contact with the outdoor unit.

However, you should also keep in mind that such noises can also be produced by dirty condenser coils or other loose components. In the worst-case scenario, the buzzing sound may be produced due to a refrigerant leak. This will put the compressor and the entire unit under extreme stress.

As a result, higher energy bills and cooling issues will become a norm. Therefore, do not ignore such sounds and act on them as soon as you first hear them.

Rattling Noises

Rattling sounds made by your commercial HVAC unit most likely mean there are loose sticks, leaves, or dirt in your outdoor condenser unit. Because the outdoor unit has to bear the brunt of the external conditions, it is common for them to make some noises.

The easiest fix is to remove the cover and stuck branches or leaves. Furthermore, in the future, if you wish to install a new commercial HVAC unit, make sure that you choose a location that is away from nearby trees, shrubs, etc.

This is because the outdoor unit should not come in contact with dead branches or leaves. During extreme weather conditions, they can find their way inside the unit and cause expensive damage.

Bubbling Sounds

If your commercial HVAC unit is making bubbling sounds, it means there is a blockage or crack in the drainage pipe. If you have the tools and know where the drain pipe is located, you can easily remove and inspect it. Inspecting and replacing the drain pipe is an easy procedure but should only be performed if you have prior experience.

Moreover, there may be a blockage inside the unit. In such a case, you should avoid accessing areas deep inside that might cause injuries or expensive damages. It would be better to call an expert and communicate your concerns.

How To Avoid Strange Noises In Your Commercial HVAC system?

It is a common belief that as long as the commercial HVAC unit does not experience a problem, there is no need to maintain it. This misconception continues to remain persistent and leaves commercial business owners with no benefit. The best way to avoid strange noises is by regularly maintaining the commercial HVAC unit.

As a business owner, it is your job to perform weekly inspections and maintenance. Plus, you should also train and educate your team to look after the unit. Moreover, the unit should also receive professional maintenance and inspection. While you may be able to clean the air filters, reaching tight areas and inspecting for cracks, rust or damages is the job of the experts.

The reason professional maintenance is expensive is that it helps avoid complications by removing them as soon as they show their first symptoms. In other words, it is an investment rather than an expense.

Therefore, your commercial HVAC unit should receive professional maintenance at least once or twice a year depending on its usage frequency. And, always hire a licensed technician to look after the unit.


Commercial HVAC units are known to make strange noises. However, the above-mentioned information and troubleshooting tips will help you get rid of and avoid all such complications at the same time. Simply make sure that you keep an eye out for unusual signs and symptoms and get help from commercial HVAC companies Smithtown for repairing and maintaining the HVAC system.

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