If you have valve core removers use them and you don't need a gauge set inline while your pulling a vac.
Designate the pump and connections as a separate piece of equipment. The center hose yellow is connected to the vacuum pump and then the new refrigerant supply bottle or can. Need to vacuum down and recharge your air conditioner system? If the system never reaches inches there is a large leak. Depending on which text editor you're pasting into, you might have to add the italics to the site name. Vacuum pumps and refrigerant manifold gauges can be rented or purchased at your local home improvement, HVAC or automotive stores.