Watts radiant heating system.
3 zones all exhibiting same issue.
Purged with 1 hp submersible pump.(manifolds done individually, the main loop, then combined)
1 zone 8 loop manifold same elevation as main loop (all runs 250' 1/2" pex)
1 zone 8 loop manifold 6 ft above main loop (all runs 250' 1/2" pex)
1 zone 4 loop manifold 6 ft above main loop (all runs 250' 1/2" pex)
All pumps Grundfos UPS 15-58 set to med.
Calculated head .03 * 250 = 7.5 ft of head
On pump curve that gives a flow rate of approx. 7-8gpm.
Test on Zone same level as main loop. 8runs
ACTUAL test results using 1HP open loop injected between exp tank/bubbler = 3.2gpm total (approx. .4gpm run)
ACTUAL test results using 1HP open loop injected directly into manifold = 4.1gpm total (approx. .5gpm run)
ACTUAL test results using UPS15-58 closed loop 12psi. @manifold
.75 gpm toatl (approx. .08gpm run)
Hi speed very little improvement.
Change to UPS 26-99 very little improvement.
Other zones exhibiting same characteristics.
To sum it up i could get my flow if i put a 1 hp circ on each zone.
But that just seem ridiculous.
Thankyou for your time and any help you may be in this issue.
P.S. Nothing helpful to say, why say it.