When designing hydronic circuits, most of us focus on what’s necessary for that circuit to absorb thermal energy at a heat source, carry it along like a conveyor belt and release that energy at one or more heat emitters.

The math associated with some of our assumptions can lead to incorrect conclusions.

Keep water moving to prevent frozen pipes and other issues.

There are advantages to using this piping configuration in hydronic systems.

Have a look at the rating tables for most finned-tube baseboard sold in North America and chances are you’ll see a footnote under the table that reads something like this: “Ratings are based on active fin length and include 15% heating effect factor.”

There are hydronic design concepts in which flow must pass backward through a non-operating circulator, perhaps thousands of times over the life of the system.

Flow reversal is possible in a P/S system, but is it practical?

When — and when not — to use reverse return piping.

Twenty years ago, the contemporary approach to prevent interference between simultaneously operating circulators in a hydronic system was primary/secondary piping.

A seemingly good idea that doesn’t work.