text: Parallel reverse return — Heating Help: The Wall
  Greg, its actually a new install from the ground up. Boiler, buffer tank, new rads, piping, etc.
  Just curious what would happen if I didn't balance and let the water flow the way water does. Would it all heat up? Or would I end up with cold rads?
  I imagine the room where the valve is very nearly closed (I can hear the water rushing through it) will have that valve wear out prematurely. This is obviously a situation where a suitable needle valve should be used, if there are any for this service.
  I do not even know if mine is overpumped or not. I have a Taco 007-IFC and the slab is about 750 square feet. Five rooms in parallel. But since I do not know the lengths, this is meaningless. I do not hear the water rushing around the pipes, except where it goes through that nearly closed balance valve (ball valve), so it is not fantastically over pumped. But I get no where near 20F drop through that slab, even when it is 5 degrees below design temperature outside. So it is probably somewhat over pumped.
  have no experience with them, but if you get the itch to modify your
  radiant system before winter, give them a try."
  I know they do. Where mine are located makes it very difficult to change the valves. I will not do it before this winter. Three of my ball valves run full open, so they should last forever. One is partly closed (less than half way, I estimate). The last one is almost off. That is the one that is likely to fail. I do not know how long it will take to erode the stainless steel ball. I suppose it is the teflon around it that will quit. I am 73 now, so I do not know if the valve or I will quit first. When the valve quits, I may put a Caleffi one in, if I still have enough marbles left to think of it.
  Actually, If I did not have two computers constantly running in there (one runs a measured 376 watts most of the time, the other much less), I could open that valve a little more and prolong the life of that valve.
  The system will be able to be converted to reset with the addition of a few more dollars if he decides, however, these customers tend to stay with the bare minimum.
  It's a shame since he is spending money to relocate the chimney and still skimps on the mod-con. Had he thrown all the money for the chimney, new dhw tank... into a pot it would all come out at the same (or close) amount, with significant more long term savings.