I wanted to say thanks to Matt/Dave at LL for responding to my "supposed" issue with the L7224 aquastat. They sent me a new one next day (it was not the problem) but great service to say the least.
The short version of the story is i have a TACO 530 feeding the aquastat L7224. The instructions say to use ZR/ZC if using a "tankless" setup, which I had intended on doing. The down side is the zone controlled circ pumps would cycle on and off with the boiler circ pump. I wanted the zone circ pumps to circulate continously until temps were satisfied while the boiler circ pump should only circulate when conditions for the boiler are met (water above LL and a call for heat) going this method of zone circ pumps turning on/off with boiler circ pump would not heat the house very well. If I made the zone circ pumps run continously while calling for heat the house heated great.
I then jumpered the TACO 503 like instructions say to make it a "cold" start system but the circ pump on boiler would not turn on. Thinking it was the aquastat's issue i had another sent. After many hours it finally registered in my thick skull that the aquastat was not getting a "signal" from the 503, I then added the thermostat line via "X X" terminal from the 503 to the L7224 and all works as I had hoped.
The system now calls for heat from thermostat which turns on zone pump (any of the three or any combination of all three). Boiler will turn on circ pump if water temp is above low level setting and circulate untill temp drops to min boiler temp , Zone pumps circulate untill temp demand is met.
This allows a predetermined minimum temp in boiler but zone circ pumps can still circulate. Better to circulate low temp(90) water than to have low temp water idle when calling for heat with a radiant floor heating system.
I still need to get the (new) aquastat sent back, sorry for that delay.