Concerned about a growing number of premature heat-exchanger failures in customers' high-efficiency boilers, management at Cardinal Heating & Air Conditioning huddled with hydronic-system manufacturers and distributors to determine the cause.The verdict: Excess minerals in water inside the hydronic systems were plugging up boilers' heat exchangers. The solution: A Hydrofill NA570924 water-treatment unit made by Caleffi.“The passageways that water flows through in low-mass (wall-hung), high-efficiency boilers are a lot smaller,” explains Craig Ouimette, the service manager at Cardinal, based in Sun Prairie, located near Madison, Wisconsin. The company installs roughly 75 hydronic systems a year within about a 60-mile radius around
