The Purpose of a Muffler and Strainer on an Inverter Mini Split

In this article, we will explore the purpose of a muffler and strainer in an inverter mini split system. These components play a crucial role in reducing vibrations, noise, and protecting the system from potential damage. Understanding their functions can help HVAC technicians ensure optimal performance and longevity of the system.

The Muffler

A muffler in an inverter mini split system is not to be confused with a copper spun filter dryer that contains desiccant to absorb moisture. Instead, it is a hollow chamber designed to gather refrigerant pulsations and reduce vibration and noise. The compressor in an inverter mini split system operates at variable speeds, and the muffler helps to dampen the pulsations caused by these speed changes.

Engineers design these systems with multiple turns and extra chambers to minimize pulsation and maintain smooth operation. These extra turns may seem counterintuitive as they can increase static and friction, potentially reducing oil flow. However, their primary purpose is to reduce system pulsation and prevent excessive noise.

The Strainer

In addition to its muffling function, the muffler also incorporates a strainer screen. This screen serves as a protective barrier, capturing any copper shards that may be present in the system. It plays a crucial role in safeguarding the electronic expansion valve (EEV) from potential damage caused by these shards.

The strainer screen is designed as a net, rather than a flat stainless steel screen, to increase surface area and minimize pressure loss. Even if part of the screen gets clogged, it still allows refrigerant oil to flow through, ensuring proper lubrication and system performance.

Vacuuming and Moisture Control: It is important to note that there is no desiccant inside the muffler of a mini split system. Therefore, extra precautions must be taken during the vacuuming process to ensure the system is free from moisture. Achieving a low micron level is crucial to eliminate any moisture before introducing refrigerant into the system.


The muffler and strainer in an inverter mini split system serve multiple functions. The muffler reduces vibrations and noise caused by variable speed operation, while the strainer screen protects the system from potential damage due to copper shards. Understanding the purpose of these components allows HVAC technicians to ensure optimal performance and longevity of the system. Proper vacuuming and moisture control are essential to maintain the system’s efficiency and reliability.

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