Patterson-Kelley has expanded its MACH Series modulating, condensing hot water boiler line. The MACH, available in 300,000, 450,000, 750,000, 900,000, and 1,050,000, achieves 92% efficiency, and under certain operating conditions efficiency can be as high as 99%. From variable operating temperatures, frequent cold starts, fast changeovers from cooling to heating, variable system flows, heat pump, radiant panel and snowmelting systems, the PK MACH Series Boilers are the future of hot water boilers.Patterson-Kelley.