When it comes to HVAC tools and equipment, the word good is not always accompanied by the word affordable from HVAC multimeters to refrigerant scales. And this also applies to HVAC vacuum pumps while buying a cheap one is a option, and what I did when I started in the HVAC field, I wouldn’t suggest it if you plan on this for a career. That being said if you are just starting out then it can be expensive to buy all the tools and equipment it takes to get started, especially as expensive as a HVAC tools can be.
When looking to buy a HVAC pump three things matter the quality, size, and the horse power. Most often HVAC technicians will buy the biggest pump they can afford and while this is not a bad idea many times it is completely unnecessary. Yes a larger pump will pull a system down quicker saving time but it also depends on the size of the unit.
CFM stand for cubic feet a minute and is how fast a vacuum pump can move air. Here is the ASHRAE recommended size to pump down a unit. Of course except for very large units any pump will eventually pump down a system given enough time.
System size (tons) Pump cfm
1-10 ton use a 1.5 cfm pump.
10-15 ton use a 2.0 cfm pump.
15-30 ton use a 4.0 cfm pump.
30-45 ton use a 6.0 cfm pump.
45-60 ton use a 8.0 cfm pump.
60 and above ton use a 11.0 cfm pump.
All of this is going to depend on the person and if they are working with commercial, residential, or both. Also as I know all too well money is always a factor, so in reality anything less then 4 CFM is usually not considered because of the time factor.
Our Picks For HVAC Vacuum Pumps 2015