Why balancing valves on both sides of the condensate loop?

Norbert

I will be doing a condensate loop for my basement, baseboard Slantfin 30, about 30ft, oil lubricated circ,Aquastat and relay for burner control, Spiro trap, bypass loop to limit outbound water temp, read Dan's book "How Come?" and paid attention to the chapter on condensate heat, have taken it to heart. Why do we put balancing valves on both sides of the radiation, would not one suffice? How do we balance properly? What delta t indicates proper flow? Are 3/4" B&G circuit setters appropriate or overkill, any other alternatives, would a full port 3/4" suffice as is used in the bypass?

PS Thanks to all the Wallies, Brad and Steamhead, and Dan's books,by replacing my 50yr old Boiler and proper sizing, replacing all the air vents, my gas bill is down 50% compared to last year. Just wait until I get to insulate!

Norbert