radiant heating zones

Brad White

I see the best combination being one of both: Continuous circulation (more important on high mass) and a control valve as an injection/mixing device.

The rationale is that constant circulation gives you much more even temperature than on-off control by valve or circulator.

Remember, when your valve or circulator first come on, your first few feet see the warmest water first; eventually the surface heats up to become it's most even. Continuous circulation removes this time lag. The valve or mixing device, especially working to slab temperature or space temperature with PID control will give you almost undetectable evenness of temperature hence comfort.

Jim Waldenberg

zonevalves or pumps

On radiant heating zones, which is the better way to go, zone valves or pumps?