One size doesn’t fit all

The Glitch:

A project requires both medium temperature (140° F at design) and low temperature (105° F at design) radiant floor panels. The system will also supply domestic hot water using an indirect water heater. The installer proposes the system shown in Figure 1. Assume each zone circuit requires a flow rate of 4 gpm when operating. Since the mod/con boiler has 1-inch pipe connections, the installer decides to use a 1 inch domestic hot water tempering valve to lower the water supply temperature to the lower temperature zones. He also decides to pipe the entire system with 1-inch tubing.

Can you spot at least six design or installation details that are going to create problems?

Are you an ace troubleshooter?

Within the pages of this magazine, PM’s Hydronics Editor John Siegenthaler, P.E., will pose a question to you, our readers, to review a system’s schematic layout and discover its faults, flaws and defects. Discover archived “The Glitch & The Fix” exercises at its radiant-focused website, www.radiantandhydronics.com. Good luck!