i simply pull from the left side "hot", the pump is just a boiler pump from Home Depot ($70). The right side is my return and i have the 2nd ball valve up top because it was the simplist way to bleed the system and not have a huge mess. You will also see on the left side top anothe ball valve with a garden hose attachment fitting. Now please i am no plumber at all, im a nurse so dont be to rough on my plumbing job!!! I would dare to say i had close to $600 in this set up, but so much more consistant and easy! I have the pipe underneath with valves that simply drain in a hurry right through the wall and out in my garden.