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Do You Have To Vacuum A Mini-Split AC System?

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After spending a good sum of money to get a mini-split system, you might be enjoying your newly cooled home, and a random thought might cross your mind; you want to know if you ever have to vacuum your mini-split to keep it running for long period of time. Believe us, you aren’t the only one who haves this question. When you purchase a new ac system, you definitely want to maintain it to keep it running properly. So, stick with this article as it contains everything that you need to know about vacuuming a mini-split air conditioner.

When it comes to cooling, nothing is better than a mini-split. During the cooling process, a lot of moisture is created in a mini-split. Moisture in air conditioner leads to many serious problems. So, any kind of air and moisture can damage the air conditioner eventually. A mini-split should be vacuumed to get rid of moisture as it reduces the performance of air conditioner by damaging it, as the condensed water inside the mini-split can cease the system. Leaks in the coils and different parts are also checked by vacuuming the air conditioner.

If you are going to vacuum your air conditioner then we need to cover a few things first. This article will help you in explaining how to choose the right tools and begin with the process.

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How do you vacuum a mini-split?

The process of vacuuming a mini-split is simple and easy and you can follow it even if you are doing it for the first time. Start by choosing the right tools for this job. Following are the tools required to vacuum the air conditioner perfectly:

  • Vacuum Pump
  • HVAC Gauges or micron gauge
  • Allen Keys
  • Mini-split adapter 5/16 to ¼ coupler

To get ready to vacuum a mini-split, you’ll need a vacuum pump and HVAC gauges or micron gauges can be used.  The vacuum pump is used to pull out any remaining air creating a vacuum. The Micron gauge is used to measure the change in pressure as vacuum pump sucks the air out (note, a Micron gauge and HVAC gauge are similar and are used for the same purpose).  

Detailed procedure of vacuuming a mini-split

Start by checking the valves of the gauge. Both high and low valves (mostly blue and red colored) should be closed. Attach the low-pressure valve to the compressor. And attach the central valve with the vacuum pump.

Now start the pump and turn on the valve attached to the outdoor unit. Let the pump run till vacuum is formed. It will take almost fifteen minutes and a negative pressure on gauge will confirm that. Now turn off the gauge and pump and wait for fifteen minutes.

After fifteen minutes if the vacuum is maintained then it means that there is no leakage in your compressor. Now you can add refrigerant. For that you need to open high and low-pressure gauge with the help of Allen keys. After adding the refrigerant, remove the low-pressured valve and a tiny amount of refrigerant will be pushed out, which is completely fine.

This is all that you need to do. If you face any problem, check out the answer below.

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What happens if you do not vacuum a mini-split air conditioner?

The primary objective of vacuuming a mini-split is to lower the pressure and clear all the air and moisture. If you do not vacuum a mini-split air conditioner before adding a refrigerant, it will result in the low performance and sometimes it can lead to a severe damage. This is because by vacuuming you make sure that there is no moisture and air inside.

The following are few problems that may occur if you do not vacuum a mini-split:

Acid Formation

We know that a lubricant is present inside a refrigerant coil. No vacuuming means no removal of moisture. In the presence of both a lubricant and moisture, a chemical reaction will be initiated resulting in the formation of an acid which can lead to rust formation on internal parts of air conditioner including crank shaft, pistons, piston rings and failure of motor winding. 

Condenser capacity will be reduced

Due to the presence of air inside a refrigerant coil, a lot of volume will be covered with the air particles, reducing the volume for refrigerant. Consequently, cooling capacity will be decreased.

Less cooling with more energy consumption

When there is less capacity for refrigerant, pressure will be increased in the condenser. As a result, compressor will be over heated. Due to this, there will be high power consumption and failure of motor winding. This increases the load on the compressor due to which cooling rate decreases while energy consumption increases.

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Does vacuuming an air conditioner remove the oil?

This is the question asked a lot by many owners that if they do vacuum their mini-split, will it also remove the oil from the unit?

Well, the answer is NO. Performing a vacuum will not remove the oil in the unit. But there are some specific conditions, like if you have done replacement of compressor or accumulator, then you should add oil into the air conditioner. One  important thing to consider is the type and amount of the oil, if  you are uncertain about this, contact some service provider or contact the company that installed the unit and ask about the type & amount of oil to use in air conditioner.

What are the advantages of vacuuming an air conditioner and possible problems caused by not vacuuming?

The air conditioning vacuum pump is used to remove unwanted air and water vapor from the air conditioning system when it is under service. There are many advantages and beneficial outcomes that you can get by vacuuming the mini-split unit.

  • More refrigerant charge

If air is present in the system, it can cause access refrigerant gasses in the tubes and refrigerating system. Ultimately, it affects the performance of mini-split and cooling can’t be accomplished as efficiently as expected

But to avoid all these issues, we use the vacuuming technique and pull out all the air present in tubes. This helps to give more space to refrigerant gasses to work and maintain the cooling process.

  • Efficiency of the condenser will increase

With long period of operation, due to some factors, air and some other gasses are produced or make their way into the tubes and condenser. Such gasses, like air, are non-condensate gasses. Due to presence of these, the condenser is unable to give its maximum output as expected.

So, vacuuming it will help to remove these gasses and helps the condenser to operate as it should.

  • Condenser pressure and temperature will remain moderate

Like any mechanical system they are designed to complete a certain function. But sometimes, various unfavorable situations occur and cause a hurdle in normal functionality . This causes the increase of load and puts added pressure on different components. Same is the case with condenser in mini-split. Due to some unfavorable gasses, it may not be able to complete its job efficiently and its temperature & pressure level can rise more than normal.

But when you vacuum all the un-necessary gasses out of the condenser, its temperature and pressure level remain normal while keeping its efficiency.

  • Compressor temperature will remain normal and performance increases

As we’ve discussed above, some unwanted elements (gas) increase the pressure and cause over-heating of condenser. Also, as various parts are attached to each other, they put impact on the other parts too. This has the potential to cause failure of compressor or system.

Vacuuming helps us to overcome this issue and maintain the performance of the mini-split air conditioner and also avoid any inconvenience with its parts.

  • More cooling and less power consumption

By purifying the gasses and remove other impurities, it enhances the capacity of the system to do more cooling in less time. Ultimately, this will help the user by reducing its power consumption.

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Why vacuuming mini-split air conditioner is important?

The two units are connected by refrigerant lines, and by an electrical cable, and can be some distance from one another. For the Aura, the maximum allowed line length is 20m, and the maximum difference in height is 8m. In addition to the lines and cable, both units have a condensate drain, which should be routed outside using pipe with a consistent downward slope. After a long period of working, some gasses are produced or make their way in the pipes and different parts.

For this reason, it is important to vacuum an air-conditioning system to remove any air or moisture that may damage the system in the long run. Moisture in the AC system is a serious problem, because moisture reduces the performance of the AC system and condensation of water can cause the AC system to freeze. Condensed water particles corrode the AC system and causes long-term damage. Creating a vacuum deep enough to boil moisture away by using a vacuum pump on a regular basis is an effective, low-cost method of maintaining a healthy AC system. Pumps can be purchased or rented, if you don’t want to make a permanent investment.


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