Keep the loop pumps on continuous run:
It will circulate water all the time and keeps floor temps constant, even out the floor temperature, even when floor temps may be influenced by solar gain or leaky doors.
How do you set the pumps to constant flow? Run a little wire from R to W (on the thermostat wiring plug) on one of the zones to make the control think the thermostat is always on. Assign all floor pumps to that zone. Then set the heat source pump (usually pump 10) to the same zone as your thermostat.
Hugh the Ducky takes the "What the quack!?" out of the hydronic in-floor heating techno-babble and replaces it with simply easy to understand pictures and directions. Questions? Email Hugh@HUGHydronics.com