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How to Choose the Right Vacuum Pump for Air Conditioning Systems

on October 10, 2022

The A/C vacuum pump, also known as HVAC vacuum pump, is one of the main tools that any HVAC technician who intends to provide an air conditioning and refriferation service in a professional manner should have at hand. Aircon vacuum pumps are relatively easy-to-use devices that help keep HVAC systems free of moisture, plus they efficiently recover and return refrigerant to the system. Surely, these machines are not something new for those who have been working for a while in the air conditioning sector; however, at Cool Tools HVAC-R, we know that the variety of vacuum pump makes and models available can be a bit overwhelming for those just starting out.

That’s why we want to summarize the most important factors to take into account when choosing and selecting a new vac pump for an air conditioning system. Whether you want to review or learn about the subject, this article will surely be very useful to you.


What Does an HVAC Vacuum Pump Do

Regardless of the brand of a vacuum pump, its function is always the same: to get rid of any remaining air and moisture (water vapor) from an HVAC system and facilitate the extraction and storage of the refrigerant for reuse later. Also, these vacuum pumps can be used to check HVAC equipment for leaks.

The presence of humidity inside an air conditioning unit after a repair or maintenance service can trigger several problems. If the system is not evacuated correctly, the water vapor in the air trapped could condense and freeze in the expansion point near the evaporator when the HVAC unit is turned back on. This freeze blockage will prevent the refrigerant from moving freely through the system. This not only will drop the HVAC unit's efficiency but also could lead to further costly repairs.

Refrigerant leaks would also negatively affect any air conditioning system. It will make the system less efficient and reduce the life of the HVAC unit. Most refrigerants are highly corrosive substances, so they can slowly corrode major components, such as a compressor when it leaks. Over time, all the affected parts will break, which could lead to purchasing new equipment.


Why as an HVAC Technician You Should Use a Vacuum Pump

As an HVAC technician, you should know that refrigerants are highly contaminant substances. That's why, under The Ozone Protection and Synthetic Greenhouse Gas Management Legislation, it has become mandatory for the refrigeration and air conditioning industry to recover, return and dispose of ozone-depleting refrigerants and synthetic greenhouse gasses.

And this law should not be surprising since, according to the Australian Refrigeration Council (ARC), one kilogram of R410a refrigerant has the same impact on the greenhouse as two tons of carbon dioxide. This is equivalent of running a car for six months.

That's why it is best to always carry an HVAC vacuum pump when you provide air conditioning services. This will help you be more professional and efficient. Remember that working outside the established norms can lead to fines and penalties.


How Most HVAC Vacuum Pumps Work

Most HVAC vacuum pump models for air conditioning services are rotary vane-type positive displacement pumps. They work by a simple but precise mechanism and it is important to know how these machines work to operate them correctly. The vast majority of these HVAC vacuum pump types are made up of two major sections. The electric motor is located in one part, while the compressor is located in the other.

On the electric motor side are both the rotor and the stator of the motor, as well as a rear fan that will regulate the temperature of the electric motor when it is running. On the other hand, on the side of the compressor, we find the inlet nozzle, the pump’s rotor and the compressor chamber.

When you connect a vacuum pump to HVAC units through manifolds and gauges and turn it on, it's not sucking per se. Thanks to their configuration, when the rotor moves around, the vacuum pump generates a low-pressure zone continuously, breaking the pressure balance between the vacuum chamber and the air conditioning unit. Due to the pressure in any system tends to stabilize naturally, moving from a high-pressure zone to a lower one, the vacuum pump drags anything inside the HVAC unit when the system tries to compensate. We suggest you check out the next video to see how all this works.


Choosing the Right HVAC Vacuum Pump

When selecting a new HVAC vacuum pump for a new air conditioning system or upgrading an existing one, it's important to consider several key factors beyond just the brand's name.

  • Vacuum capacity. Air conditioning and refrigeration system equipment vacuum is recommended to be less than 1000 microns to remove moisture and less than 500 microns after replacing a compressor. Some equipment manufacturers require 400 microns to ensure harmful water vapor is removed from the system. A high-quality AC vacuum pump will be able to get it down to 200-500 microns or even 50-100 microns.
  • Speed. Most vacuum pumps for air conditioning services are rated by the amount of air they can handle. The ability of one of these pumps to handle a given airflow determines how quickly the job can be done. Airflow measurement is often referred to as CFM or cubic meter per minute. HVAC Vacuum pumps designed to handle between 4 to 5 CFM are intended for residential air conditioning systems. In contrast, it is best to use a refrigeration vacuum pump that can handle at least 6 to 8 CFM for commercial systems.
  • The stage numbers. Some HVAC Vacuum pumps are 1-stage rotary vacuum pumps, while others come with a 2-stage configuration. These HVAC vacuum pump types offer the same function, but as the video above indicates, a 2 stage vacuum pump offers slightly better cleaning performance due to its design and functioning.
  • Facilities. Not all HVAC vacuum pump models have the same features. We suggest first evaluating the size of the oil fill opening, as the larger the opening, the faster and easier it will be to change the oil. Second, check whether or not the pump comes with gas ballast to help mix atmospheric air with the exhaust gas, which will prevent condensation and moisture formation in the pump oil to keep it clean for longer. Finally, check to see if the pump has a vacuum gauge that lets you know the level of vacuum in the system while the pump is running.

Other Considerations:

  • Weight
  • Body Dimensions
  • Noise levels
  • Cord length
  • Sight glass
  • Oil capacity


Purchase Your New HVAC Vacuum Pump at Cool Tools HVAC-R

At Cool Tools, we pride ourselves on being one of Australia's leading HVAC service tools and instrument suppliers, so if you are looking for a new AC vacuum pump, you have come to the right place. We offer a wide variety of vacuum pumps and vacuum pump oil from the most recognized brands in the industry, such as RobinairFieldpiece, MatercoolJavac and many more.

Our online store is designed to provide you with a convenient shopping experience, and our HVAC tools and products are broad enough to cover larger residential and commercial services. When you make a purchase from Cool Tools, you can be sure that you are getting the highest quality product. We offer a one-year warranty on all of our air conditioner vacuum pumps, so you can be sure your investment is secure.

We are passionate about helping our customers get the most out of their HVAC system, and we are confident that you won't find a better selection or better prices anywhere else. So if you're in the market for a new air conditioning vacuum pump, make sure to give us a call. We'll be happy to help you find the perfect product for your needs.



When working with air conditioning or refrigeration equipment, it is essential to have a quality vacuum pump on hand. These devices allow you to remove unwanted air and moisture from the system, ensuring that the job is done correctly. Vacuum pumps are typically classified according to their airflow, vacuum capacity, and number of vacuum stages.

Cool Tools HVAC-R offers a wide selection of high-quality air conditioner vacuum pumps to cover any situation. Our experienced staff is always available to provide personalized guidance and ensure that you find the perfect pump for your needs. Contact us today to learn more about our products and get started on your next project.