Effective high-quality reflux distillation includes two points of condensing, even if you don't see it.
For the T500 and T500 Pro, the coil inside the reflux column uses the cooling water that has travelled through the product condenser to also provide some knock-down cooling to improve refluxing in the column before flowing out of the water outlet.
In the same way, one VORTEX unit serves as a reflux condenser, and the other unit works as a product condenser.