How To Stop AC Refrigeration Line From Vibrating?

A vibrating AC refrigeration line is annoying, especially next to a room. Worse, it can break the line, translating into a disaster. How do you stop the refrigerant line from vibrating? 

To stop the AC refrigeration line from vibrating, ensure the connections are tight,  lubricate the motor, and keep the AC clean. Installing add-ons can also fix the problem, such as line weight and vibration dampeners. 

In this article, I’ll discuss solutions worth trying if your AC’s refrigeration line vibrates. It’s best to solve the issue immediately before it can lead to worse problems. 

1. Tighten the Connections

The refrigerant line connects the indoor unit and the condenser. 

You must seal the connections properly to prevent dirt and debris accumulation, which can negatively impact performance. Not to mention, there’s also a tendency to vibrate when these connections aren’t tight

One of the first parts to check is the compressor mounting bolt. You might haven’t installed it properly, or it could have loosened over time. It can loosen due to spring winds or when hit by any object. 

A quick fix is to tighten it by hand or use any appropriate tool. 

Read: What Does A Condenser Do In A Refrigeration System?

2. Replace the Compressor Grommet

A high-quality compressor grommet is a foundation that keeps an AC quiet as it operates. Because of the grommet’s location under the compressor, it needs customizations to ensure optimal vibration absorption

The refrigeration pipe system’s natural frequencies vary. Hence, you need to find a mounting grommet that matches. Here are the crucial considerations when looking for a compressor grommet. 

  • Size
  • Tensile strength 
  • Material 
  • Compression set 

Natural rubber is a great option, which can stand many years of use. Find one with high-strength construction that’s also easy to insert. It would also be best if it’s customizable to ensure the right fit, depending on the line size. 

Have a Question? Ask HVAC Technician

Click here to use the chatbox to speak with one of our technicians.
No in-home service calls. No appointments.

Aside from natural rubber, EPDM is also a common grommet material. Ethylene propylene diene monomer is a synthetic rubber with a chemically saturated backbone. It resists outdoor conditions, making it an excellent choice for a compressor grommet that prevents the AC line from vibrating.  

It’s also crucial for the grommet to have a low compression set. Without a suitable compression set, it won’t bounce to its original shape as it moves. 

Read: Commercial HVAC – Everything You Need To Know About

3. Add a Line Weight 

As the name implies, line weight is an object heavier than the refrigeration line, which can add weight and prevent excessive vibration. Typically, it weighs 2 pounds (0.9 kilos), but it can also be lighter or heavier, depending on the weight of the line or pipe it needs to support. 

The rule of thumb is to position the line weight next to the part of the refrigeration line that produces the most vibration. It’s available as an aftermarket part. 

However, any heavy object will do when a line weight is unavailable. For example, you can strap a piece of steel in the refrigeration line using a hose clamp.

Read: R22 Refrigerant – Everything You Need To Know About

4. Provide Adequate Support 

The weight of the refrigeration piping can contribute to its vibration. It can also be more prone to shaking if it’s too long. 

An easy solution is to ensure adequate support. Having something that holds the line can prevent it from moving a lot. Aside from vibrations, lack of or inadequate support can also break or bend the line. 

Section 305 of the International Mechanical Code provides guidelines on proper support for refrigeration pipes or lines. It suggests the maximum vertical and horizontal support spacing necessary. While the code isn’t legally binding, the recommendations can be helpful. 

Pipe clamps are among the most popular tools that can support refrigeration lines. They’re available in different types, including those with screw mounts and squeeze-fit threads

Read: What Are 4 Basic Categories Of HVAC Systems?

5. Install Sound and Vibration Dampeners 

One of the possible reasons for the vibration of a refrigeration line is the motor or compressor. The copper conduits connected to the AC vibrate as the compressor pumps refrigerant into the system. You can learn more about refrigerants in my article, which details the different types of refrigerants and how they work. 

While sound and vibration dampeners can help, not all of them are the same. Consider three essential factors when choosing the right one. 

  • Weight/Cut length
  • Part’s resistance
  • Fit 

Like line weights, the dampeners must have the correct weight that suits the refrigeration line. It’s ineffective when it’s too lightweight. On the other hand, it can only exacerbate the vibration when it’s too heavy for the system’s requirements. 

Environmental factors are also vital considerations. Exposure to elements can cause premature wear, so consider material and durability. Otherwise, they will deteriorate quickly and will become ineffective. 

6. Avoid Overcharging 

Refrigerant overcharge is another common reason for line vibrations. It alters the pressure in an AC, endangering the compressor. It happens when the piston cylinder floods because of the extra refrigerant, also known as slugging. 

Proper installation is essential to avoid overcharging. Only licensed professionals can work with refrigerants, so let them do their job. Amateurs can put too much refrigerant than necessary. 

More than just noise and vibration, overcharging the refrigerant will have more severe consequences. For instance, it can enter and burn the compressor, resulting in costly repair or irreversible damage. 

7. Lubricate the Motor 

Anything that causes the AC to vibrate will have the same impact on the refrigeration line. And one of the potential culprits is the fan’s motor. Metal-on-metal friction can contribute to premature wear. When the motor has excessive vibration, the refrigeration line will also move. 

Lubricating the fan’s motor requires using a multipurpose oil. Add a few drops on the base of the motor, specifically on the part that connects it to the fan. Tighten all connections to prevent the fan from shaking and the refrigeration line from vibrating. 

8. Clean the AC

Again, the refrigeration line will vibrate if the motor of the AC vibrates. One of the reasons for such vibration is a dirty unit. Hence, you must spend time cleaning the unit to optimize its performance and reduce vibrations

Use different tools to clean the AC, from a wet vacuum to a handheld compressor. If you aren’t confident in your knowledge and skills, hire a pro to do the job instead. This way, you can have peace of mind while also ensuring your safety. Remember, the AC contains coolant, a chemical with serious health risks when mishandled. 

9. Replace the Refrigeration Line 

The connections and joints in an AC wear out over time, including the refrigeration line. It erodes as a result of exposure to outdoor elements and old age. 

When such happens, it becomes weak. In some instances, they can still be functional but with some problems, including vibrations

If the refrigeration line is damaged or too old, consider a replacement to prevent it from vibrating. Proper installation is a must. Choosing a suitable material is also essential. A steel braid can strengthen it, providing the necessary support to prevent the refrigeration line from vibrating. 

Soldering might be necessary for the new refrigeration line depending on the material or type. Clean the copper pipe before you start to make the connections more reliable. Using the right heat is also critical to get the job right. 

Ensure your AC’s new refrigeration line or piping is the right size. The YouTube video below shares some tips to keep in mind when looking for the right size refrigeration line. 


The refrigeration line can be prone to vibrations if you don’t install it correctly or if there are problems that cause excessive motor or compressor movement. Consider the recommendations above to avoid unnecessary vibrations from using compressor grommets to lubricating the motor.