The odd thing is, before I did the prime/sec loop, this same system pump supplied the same zone and satisfied it with a 100k oil boiler...
Why? My assumption is, that with the new set up, and the supply lines now getting fed by a 'tee' and a pump on the primary loop, probably 50% or less head is now available to the system pump/heat zones...and for this one troubled zone, it probably was just enough to push it past the tipping point.
So I am begining to conclude that I need a substantially larger system pump. I just measured all the footage of copper pipe, and counted up all the 90's and 45's on that zone, and measured the elements. I was astounded.. ( I did not install this zone!.. )
I came up with the following: Total length of 3/4 inch copper pipe: 284 ft, of which sits (first in line) 11 ft of HO element, and then another 34 ft of regular element..the return pipes loop back over the elements..
Number of 90's: 40
Number of 45's: 13
A whole lot of info in the previous posts. I am certainly confused as to what you have, what you tried and what you want.
It appears the first thing we need is a schematic of what you got. Boiler pumps, primary pump, system pump all on a 1" header - a lot of pumps for that small pipe. But zone valves? Yes, it is easy to overwhelm a 007 with too many zone valves. That is why I favor pumped zones over zone valves. Especially when forced into larger pumps. Pumps are about as cheap as zone valves and then then loops are easier to balance or if done right - don't need balancing.
The one zone you mention with 284 feet - does it go over to the neighbors house first? Certainly excessive.
The LL110 boiler is a sports car with a v-8 burner. Low mass with high input. It will swing with load and response. Proper boiler pump control is a must for this boiler. Even with my K-6 and it's 50 gallons of mass, it will bottom out on load and rely on the aquastat to shut off the boiler pump until the burner catches up.
Sting is simply trying to teach you the ZEN of hydronics, Grasshopper. If you come for advise, you must also listen to wisdom. Controls and design must be married properly. One good control layout may not apply to another good piping layout.