Best AC Vacuum Pump of 2021: Complete Reviews with Comparisons

When servicing your air conditioning unit, you want to make sure that you are not only making repairs for solving the immediate issue, but you also want to ensure that when replacing any components within any refrigeration system, that your repairs last.

So, how do you narrow down your options to find the best HVAC vacuum for you with so many options out there? Simple! Just keep scrolling to find out our list of the best HVAC vacuum pumps of 2021.

The ZENY 3 rotary vane vacuum pump is an excellent single-stage for personal use. Its heavy-duty aluminum alloy casing provides durable and quiet operation despite being single-stage. It is lightweight and easily portable with its non-slip cushion handle.

Product Highlights

If you are looking for a low-cost vacuum pump to use for lighter HVAC works, consider the ZENY 3. The ZENY 3 effectively cleans smaller split systems under 10 tons without breaking the bank.

The ZENY 3 is fitted with a few convenient safety switches and features making it easy to use for any home operator doing some DIY HVAC work, or newbie technicians testing the trade. 

What’s to Like About the Zeny 3 Rotary Vane 5 Cfm Single-Stage Vacuum Pump

Don’t let this single-stage fool you; it features a direct-drive motor and on/off switches for easy, maintenance-free starting. Its exhaust port and exhaust cap expel air and vapor from the system keeping it running clean and efficiently over time. The high-powered internal cooling fan prevents the vacuum pump from overheating. 

This budget-friendly buy has a durable shock-proof base. Despite being a single-stage vac pump, the ZENY 3 runs quietly.

What’s Not to Like About the Zeny 3 Rotary Vane 5 Cfm Single-Stage Vacuum Pump

This is not the vacuum pump you want to use to replace a reversing valve on a 50-ton package unit or commercial chiller. This a budget option for small DIY HVAC works where you'll only be using a few times a year.

Also, some users claim to have issues with oil leaking early on from multiple places and found difficulty in seeking resolution through their customer service. Keep that in mind before you buy. 

What Is a Vacuum Pump?

The primary function of a vacuum pump is the same regardless of the type you own. Whether they are for home or commercial use, they remove air, water, and vapor from a refrigeration system, cleaning it for maintenance or repairs. 

Once a technician has identified and repaired any leaks or issues within your air conditioner system, they will always want to recharge the unit. Before doing so, it is crucial to remove the unwanted water, air, and gas to prevent the oil from running into sludge and causing other damages.

Main Parts of a Vacuum Pump

An air conditioner pump’s essential components are the motor, compressor, handle, and support base. Within the pump, an inlet removes air from the system and exhaust to disperse it into the atmosphere.

The Motor

At the back of the motor, you will find the fan and protective casing. Within the motor, there is the stator with coils. Like motors found in other systems, copper coils wind around the motor in an air conditioner pump, which creates an electrical current. The current flows through the coils to make a magnetic field. 

In a rotary vane and other versions of a pump, the electrical current’s magnetic field rotates the rotary to create the pump’s vacuum effect.

The Compressor

Unlike the standard household vacuum, which creates a sucking force, an HVAC pump requires an air compressor to create the vacuum. The compressor makes a lower air pressure than the one inside the HVAC system, causing air from the system to flood the compression chamber to fill up space.

A more robust air compressor will make a better vacuum, but they are rather noisy. Humid climates can also break down air compressors.

Handle

On a standard pump, the handle is on the top of the unit for easy usage and maneuvering.

Support Base

The support base is located at the bottom of a pump and is for stability.

Inlet

The inlet is responsible for removing the air from the air conditioner system. The inlet connects the pump to the air conditioner unit to start the vacuum process.

Exhaust

Typically located on the back end of the pump, the exhaust disperses what the pump collects.

Types of Vacuum Pumps

There are several different types of pumps to consider when weighing out your options: rotary vane, vacuum generators, and diaphragm. 

In addition to these variations, you will also have the option of finding a pump that is either one- or 2 stage.

The two most significant deciding factors on deciding which is the best HVAC vacuum pump for you will be both the size of your unit and your overall budget.

Rotary Vane

A rotary vane pump is the most common for HVAC work. A rotor mounted inside a cylindrical housing removes gas and moisture molecules by creating a suction that compresses the air inside the pump chamber. 

Unique to this pump, it is oil-based, using the oil to pump a vane, creating the vacuum. Rotary vanes are a great, inexpensive option that can make a 99.9% vacuum in many models.

Benefits of a Rotary Vane

Known to be widely popular for use on air conditioning systems, some of the benefits of working with a rotary pump include:

Oil Seal

Because the rotary vane HVAC vacuum pump is oil-based, the oil can act as an effective seal on the pump. As a result, a rotary style pump creates an ultimate vacuum.

Prevents Wear

The oil found in a rotary vane pump acts as lubrication on the aluminum blades, rotor, housing, and housing cover bearings. Through heavy lubrication, these elements are essentially wear-free, making them long-lasting.

Reduces Operating Temperature

Friction is reduced in the compression chamber of the rotary vane pump, minimizing the amount of heat created while operating. Reducing heat can also act as a component for reducing wear and tear on your rotary pump.

Corrosion Protection

The oil within the rotary pump also acts as a protective shield on the components of it. The possibility for corrosion is limited, and the oil guards the pump against potential reactions to any gasses it may encounter.

Cleans

The compressor chamber of a rotary pump remains cleaned from the oil going through it. Keeping the internal components clean helps to aid in the lifeline of the entire HVAC vacuum pump.

Parts of a Rotary Vane Vacuum Pump

Rotary vane HVAC vacuum pumps design consists of the same standard components. You will generally see the following standard components in both oil-lubricated and dry-running rotary pumps. At the same time, you will find variations in parts based on design, size, or model.

• Blades, or vanes
• Rotor
• Cylindrical Housing
• Suction Flange
• Non-Return Valve
• Motor
• Oil Separator Housing
• Oil Sump
• Oil
• Filters
• Float Valve

Generally, the rotary vane vacuum pump is easy to operate but will require additional maintenance to keep it running smoothly. It will require regular oil changes to ensure it runs its best for as long as possible because it runs on oil. You can keep an eye on the oil fill for low levels and additional build-up. Even though handling the oil can be a bit of a pain, these pumps have proven to be the most effective for an extended amount of time.

Vacuum Generator

Vacuum generators are known to rapidly pull moisture from the air, making them excellent options for HVAC vacuum pumps. Air is drawn in and then compressed as it passes through the vacuum generator’s nozzles at a very high speed. Overall, vacuum generators create high-speed airflow, but they are not long-lasting as they require constant airflow for drawing.

Benefits of a Vacuum Generator

• High acceleration
• Control grippers individually
• Centralized and decentralized capability
• Varying power classes available

Even though generators can quickly pull moisture from the air, you will find that they are costly and may not be best suited to all budgets.

Diaphragm Pump

Also known as membrane pumps, diaphragm pumps use positive displacement to work as HVAC vacuum pumps. As a replacement to the water jet pump, diaphragm pumps have proven to be a more environmentally friendly option. 

Benefits of a Diaphragm Pump

• Dry compression avoids waste
• Minimal and straightforward maintenance required
• Low-cost spare kits available

While diaphragm pumps can create a vacuum, they are nowhere near as complete vacuums as air compressors. Diaphragm pumps are most commonly found in hospitals and laboratories but are not good options for HVAC work. You will not often see these for HVAC purposes but as small dry backing pumps in larger high systems.

How to use a Vacuum Pump for AC

Usually, you will hire an HVAC professional to perform your air conditioner pump. There are residential HVAC vacuum pumps that allow you to service your unit on your own. There are three general parts to follow to use your pump. Follow these steps to clean out your unit on your own using HVAC vacuum pumps.

Part 1: Set Up Your Pump

Before you start using your air conditioner pump, you want to make sure everything is ready so you do not have any issues.

If you follow this three-part system, you will fully evacuate your air conditioner, making it ready to be recharged or repaired as needed.

Fill with Oil

Assuming you are using a rotary pump, make sure to fill it with clean oil before use. Locate your pump’s oil fill cap, usually on the top of the system, and check on the interior edging for a fill line. Make sure you fill the oil until it reaches that line, and be sure to close the lid tight.

You want to make sure you are only putting oil in your pump for that purpose. Substituting with other mechanical oils could reduce your pump’s overall performance and negatively impact the machine itself.

Attach Gauges

Before starting, attach all of your gauges to the ports. The gauges will connect the pump to the pressure ports in your HVAC system. Most gauges and hoses are color coordinated and are meant for use as follows:

• The yellow hose connects your pump to the system
• The red gauge connects to the high-pressure service port
• The blue gauge connects to the low-pressure service port 

It is crucial to ensure that all gauges and gauge hoses connect tightly to prevent harming your pump’s overall performance.

Open Manifold Valves

Use the valves on the unit that open and close the service port. Responsible for servicing the refrigerant lines, you want to make sure your valves are closed, and your gauge shows little to no pressure reading.

Part 2: Pulling Your Pump

Once you have ensured that your machine is ready to go and everything connects correctly, you can turn your pump on.

Start Pump

Use the indicated power switch on your air conditioner pump to turn it on. Once your pump is on, you should be able to hear the unit running. 

If you are using your pump in the cold weather, make sure you open the intake ports until the pump reaches a regular speed. Once it hits an average rate, close it off again.

Open Side Gauge Valve

Once the air conditioner vacuum pump is on and running, you can start pulling the air out of your unit with your vacuum system. To do this, you will need to open up the valves on each side of each gauge.

You can refer to the manual that came with your vacuum to figure out which way you will need to turn your valves to open them.

Run for 15-30 Minutes

You will want to let your air conditioner vacuum pump at its full operating speed for a minimum of 15 minutes, but no longer than 30. This time frame allows your vacuum to pull the air out of your system entirely. Based on the manufacturer’s recommendations for your specific vacuum pump, you can check the operating manual to find the exact amount of time needed for your unit.

As a rule of thumb, you always want to let your vacuum pump run at least until the measurement is below 1,000 microns. If able, try to get the measure to 500 microns for optimal results.

Part 3: Closing Your Vacuum

Once your vacuum pump has run for 15-30 minutes, depending on both your air conditioning unit and your pump, you will want to begin closing up your vacuum.

Close the Low-Side Valve

The first valve to close will be the low-side gauge, which is typically blue. Once you have done this, let your pump hold the vacuum for around 15 minutes. 

If you find that, for some reason, your pump is unable to hold it for this long, you probably have a leak somewhere and will need to replace some component within your pump.

Shut-Off Pump

After 15 minutes of holding, you can shut your pump off using the same indicated switch used for turning it on. Before you entirely disconnect the system, be sure to let the vacuum disengage.

Disconnect Vacuum

Once fully disengaged, you can begin disconnecting the hose leading to your vacuum pump.

Purchasing an AC pump can be a big decision, whether it be for your home or business. Make sure you know all of the facts before deciding which is the best HVAC vacuum for you. Take a look at some frequently asked questions to better your understanding of vacuum pumps.

Why Do You Need a Vacuum Pump?

Vacuum pumps remove liquid and gas from your system that can otherwise lead to recurring system issues. Some of the problems include; reducing system efficiency, causing a short circuit, or creating a sludge that will wear down your system over time. In addition to increasing your air conditioner system’s life, vacuums can also help check for system leaks.

Vacuum pumps can also be helpful when working on a car, small appliance, or sewage or water lines.

How Do I Choose an HVAC Vacuum Pump?

When looking for the best HVAC vacuum for you, whether you are looking for residential or commercial purposes, you want to look at both the pump’s quality and functionality. Some things to consider should be:

Extras

There are many standard features found in vacuum pumps. Some of these features will include a CFM rating and a continuous use motor. While you want to make sure your pump has these features, also consider extras such as safe surge protection, protection from backflow, and even the ability to vacuum indoors.

Quality

The rubber seal rings in your exhaust port and oil caps are elements you want to make sure are built on quality as they can wear down the system the fastest. You also want to ensure you are looking for a pump that has a strong body. The last thing you want to worry about is accidental damage to the vacuum from bumps in storage or during moving.

Ease of Use

While ease of use is an added commodity, it is always nice to ensure your purchase is one that you will operate without challenges. One primary feature that will make your vacuum pump easy to use would be an oil sight glass (for a rotary vane vacuum pump). Other ease of use features includes oil refill ports, which help for faster, spill-free refilling.

What Size of Vacuum Pump Do I Need?

The simplest way to determine the CFM of the pump you will need is to take the square root of the tonnage of the unit you will be servicing. Typically, residential systems require 4-5 CFM, and commercial or rooftop systems will need up to 6-8 CFM.

What Does 2 Stage Vacuum Pump Mean?

Both 1 and 2 stage pumps use one stage to create the vacuum. What separates the two types is the second stage of the two stage, which establishes a secondary vacuum resulting in a stronger draw and overall tighter suction. A more sealed vacuum will leave you with a cleaner system, but having a 2 stage can come with a hefty price tag.

Do You Need a Single-Stage or Two-Stage Vacuum Pump?

Both a single-stage and a two-stage pump will effectively remove moisture and contaminants from your system. A two-stage vacuum pump tends to make less noise and provide a faster evacuation and cleaner overall process.

Don’t forget that because two-stage pumps will provide a higher quality service, they are more costly than a single-stage pump. A single-stage vacuum pump is more than sufficient for residential use, while a two-stage tends to be better for commercial use.

What Is a CFM Vacuum Pump & Do You Need One?

The term cubic feet per minute (CFM) refers to the draw on a vacuum pump. It measures the airflow volume based on how many cubic feet of air passes by a stationary point in a single minute. 

To estimate what your CFM will need, you can look at the tonnage of the system. By taking the square root of your system’s tonnage, you will find the approximate CFM required to be effective for your CFM vacuum pump. 

In a standard CFM pump, the suction increases when airflow decreases.

What CFM Vacuum Pump Do I Need For Automotive?

1.5 CFM and up should work fine on an automotive air conditioning unit as you're pulling down a system of smaller capacity. 

Why Do I Need to Change My Vacuum Pump’s Oil?

Unlike cars, an A C vacuum pump doesn’t have oil filters, so that the oil can become easily contaminated. If the oil in your vacuum becomes contaminated from outside materials, you run the risk of reducing your vacuum’s efficiency. 

Why Is My Vacuum Losing Power?

One common thing to look for if your vacuum pump seems to be losing power is to check that the hoses are tightly connected. If you are still losing power, you might have a leak somewhere and likely need to replace your pump component.

What Is a Gas Ballast and Why Is It Important?

Before the pump releases condensation, a gas ballast allows the outlet valve to open. Gas ballasts are essential because they increase the base pressure of a vacuum pump and enable the system to bypass the oil to keep the system cleaner longer.

What Is a Micron?

Another standard unit of measurement when dealing with units and vacuum pumps, microns serve to measure the strength of the actual vacuum. To fully evaporate and remove water from the air conditioning system, you will need a minimum of 500 microns of vacuum.

On a full spectrum scale, zero microns is the perfect vacuum, and on the other side of that, 760,000 microns is a space with no vacuum at sea level. Taking this scale into consideration, air conditioner vacuums with a lower micron rating will vacuum overall quicker and more efficiently.