How To Use A Vacuum Pump For An AC

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The use of an AC vacuum pump is necessary to pull out the air and the moisture. Because the presence of air and moisture causes serious problems by condensing the water particles. The presence of moisture directly affects the performance of an AC.

It is important to remove air and moisture regularly. Vacuum evacuates all the air and moisture from the refrigerant system. It is usually done before repairing and recharging the air conditioners. This process is done by professionals who know about the process. But if you want to do it at home, you have to learn the process. It might be helpful.

Steps Involved In An AC Vacuum 

Following are the steps that are involved in an AC vacuum.

Step 1: Set The Vacuum Pump with Vacuum Oil

 Before starting the process there is a need to set up the vacuum pump first. Another material is vacuum oil. On the top of the pump, there is a cap. Unlock the cap from the top of the pump and fill it with vacuum oil until it reaches its maximum level. Always use a quality rich vacuum oil than other oils. Other oils will affect the performance of the vacuum.

Step 2: Connect The Gauges To The Pressure Ports

After filling the pump with vacuum oil there is a need for a gauge set. The gauge set connects both pressure ports and vacuum to the AC system.

In the set, there are three classes of gauge the blue gauge, the red gauge, and the yellow gauge. The blue gauge connects to the low-pressure port. The red gauge will connect to the high-pressure port system. And the yellow gauge will go to the vacuum. Make sure all the connections are connected tightly. If there is any loose connection it will affect the vacuum

 Step 3: Open The Valves

After the gauges are connected in place, there is a need to use the valves of the AC system. That opens and closes the port service. By closing the valve there is no reading of the pressure.

Step 4: Turn On The Vacuum Pump

When all connections are fixed surely, it is time to turn the switch on. There is a switch on every kind of vacuum. By turning it on, it creates sound or light.

It indicates that the machine is ready to work. The action of pulling absorbs all the air and the moisture from the AC. If you are pulling the vacuum in winter then open the intake ports. After the normal speed, close the intake ports again.

Step 5: Time For The Vacuum 

The process of removing air and moisture takes 15 to 30 minutes. During this time keep the device at its full speed. The duration of the time will vary according to the recommendation of the manufacturer. So also check the manual that came along with the vacuum.

Step 6: Closing The Vacuum

 Once you run your system for sufficient time, close the system. First of all close the valve which is connected to the lower side. Let the pump hold the vacuum for 15 minutes. If the pump does not hold the vacuum for 15 minutes, indicates that there is a leak in the components.

Then replace the parts of the vacuum pump. Then switch off the pump by the same button you turned the pump on. When the vacuum is disengaged, disconnect the AC vacuum and the hose leading to the pump.

Now, the AC system is fully vacant of all the air and moisture. At this point, the AC system is ready for the processes such as repairing and recharging.

Why It Is Important to Vacuum The AC System

It is important to vacuum the AC system for its better performance. The reason behind evacuating the air is that its presence would directly affect the system. By vacuuming, you can also remove the dirt and dust that accumulated in the AC system over time.


Now, you know how to use the vacuum pump for an AC. The air and the moisture both are dangerous for AC performance. Here you need to remember one thing about vacuum oil. Use quality-rich vacuum oil. Mineral oil is a quality-rich oil usually used in it. Make all the connections carefully.

There should be no loose connection that makes trouble. There should be no air and moisture before the repairing and recharging. In case of any doubt take your car to the professional.

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