agree. maybe it's a good idea to put a balancing valve on the loop, i.e. the thick green line.The thicker pipe is a loop in itself, and is not broken at any point. The circ of the radiant loop pulls water from it in varying amounts as the radiant loop warms up. But the flow through the thicker green line must remain some what constant no matter how much water the radiant loop is or isn't pulling..
Nope, it needs to be free flowing, no balancing valve, as the amount of return water from the radiant loop will vary. So the boiler circ will respond to the head pressure as needed without a balancing valve. And a balancing valve could hurt flow rate.agree. maybe it's a good idea to put a balancing valve on the loop, i.e. the thick green line.