in essence, it is the pressure drop through the longest EQUIVALENT circuit. this can be the physical longest, or the one with a lot of restriction. thee is a formula to size the pump using this information to tell you if that little 007 is right or not.
Are all 17 loops controlled by one thermostat or are there multiple zones and zone valves?
As others have said, there's probably both a pump size issue as well as a balancing issue between all of the circuits you have.
Drewski11, we have one thermostat. There are valves on each of the four tubes running off of the _radiant-floor manifold_. There was a differential controller for pump on the radiant-floor loop, but we removed it because we are not using the solar system as a heat source. The radiant-floor loop pump now runs all the time.
If I can figure out how to upload pictures, I'll try to do so.
Mother, it is impossible to offer specific advice on something we can't see. seems that you are interested enough to seek some preliminary advice you'll now seek out someone who can try to document what you have installed to first understand BEFORE they can offer intelligent solutions and not best guesses or opinions.
Your original permit info on file with the Municipality for instance. You can check on that but if not available then some educated guesses might be in order,
Happy New Year