Hi isettateam, merry Christmas. When we plan to acquire a vacuum pump, we have to take into account three fundamental basic things: its quality, its size and its power. Most refrigeration and air conditioning professionals buy the largest pump that their economic power allows. Although the vacuum pump, turns out to be something essential, it is often not necessary to have to acquire the largest and most expensive. The deeper and better the vacuum, the more contaminants trapped in a system will be removed. For the refrigeration professional, this tool is essential if you want to guarantee the quality of your work. It is true that a larger pump will do its job faster, allowing us to save time, but this also depends on the size of the system that we are servicing. Vacuum pumps for refrigeration, usually bring value or speed printed on their characteristics with They do their job. The acronym CFM (cubic feet per minute), or L / M (Liters per minute) will tell us how fast our pump removes air and moisture. Next, I detail the recommended capacities for different refrigerating powers: 1 to 10 TR: use 1.5 CFM or 42 L / M pump 10 to 15 TR: use 2.0 CFM or 57 L / M pump 15-30 TR: use 4.0 CFM or 113 L / M pump 30-45 TR: use 6.0 CFM or 170 L / M pump 45-60 TR: use 8.0 CFM or 226 L / M pump 60 or more: use 11.0 CFM or 311 L / M pump * TR = Refrigeration ton * 1 TR = 3,000 kcal / h = 12,000 BTU / h Luck. S @ lu2 friovega63.