What Size Vacuum Pump for a Mini Split?

Your ductless mini split needs a vacuum pump for its installation, a device that can pull gas and air molecules into a sealed area. Most vacuum pumps have two jobs, sealing and cleaning.

In the case of the mini split vacuum pump, it will recover refrigerant gases, which you’re often legally mandated to do.

Even if your state or city doesn’t have any sort of such legislation, you shouldn’t want refrigerant remaining in your mini split system. The refrigerant, when left to linger too long, can mix with moisture and begin to corrode. That corrosion can spread to other parts of your mini split system as well, causing real trouble.

You want a functioning vacuum pump for your mini split system, but you have no idea what size pump is the most appropriate.

To answer that, you first need to know the cubic feet per minute or CFM. The vacuum pump CFM is the capacity of the vacuum pump, you should go by how many stages the vacuum pump has.

If you use a commercial air conditioning system and your AC is the same amount of tonnage, your vacuum pump should have a CFM rating between 6 and 8.

Taking the time to determine what vacuum pump size you require is critical. If you only need a 6 CFM vacuum pump but you buy one that’s 8 CFM, you won’t have to worry about whether the vacuum pump can do the job.

Instead, you should be more concerned that you overspent on the pump. Your mini split vacuum pump never has to work at full capacity, also keep in mind it’s only needed for the installation not for continued use of the mini split system. While that will increase its longevity, if you only needed a 6 CFM pump, then you should have bought a 6 CFM pump.

If you need an 8 CFM pump but all you have is a 4 CFM pump, you’re going to have an even bigger headache. The mini split vacuum pump does not have the capacity nor the power to provide enough pressure.

When using the vacuum pump, it will not be able to recover the full amount of refrigerant gases. The leftover refrigerant in the system will eventually affect your mini split, even if it doesn’t happen right away.

As mentioned earlier, corrosion of internal components due to the excess refrigerant is certainly a risk, as is the refrigerant gunking up internal components of the mini split system and preventing them from working.

Take the time to find a quality vacuum pump for your mini split and double-check that it’s the correct size before you get it installed. It’s for the good of your mini split!