Seemingly simple
The Glitch:
A homeowner hires a heating contractor to upgrade his propane-fired cast-iron boiler to a mod/con boiler. The cast-iron boiler is only 15 years old and in good shape. The homeowner asks if the contractor can reuse it to add heat to his 18,000-gallon in-ground swimming pool. The installer knows that this is possible using a heat exchanger. The installer also knows that the relatively cool pool water could cause sustained flue gas condensation in the boiler, and therefore decides to use a “bypass loop” with a separate circulator as shown in Figure 1. Because the repurposed boiler will be located in the pool house, the entire system up to and including the primary side of the heat exchanger is filled with 50% propylene glycol antifreeze. Can you spot several details that will lead to problems in this layout?
ENLARGE
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!
