The MACH® condensing boiler from Patterson-Kelley increases turndown, with emphasis on system efficiency, reliability and serviceability. By using a mechanical method to achieve higher turndown, it eliminates the need to add excess air, which can reduce the dew point of the flue gas and adversely affect efficiency, the company notes. It is available with 10:1 mechanical turndown capabilities for natural gas models C750, C900, C1050, C1500 and C2000; and it is suitable for a variety of applications. It has the flexibility to match input to the building load, and better control over temperature differential between return water and exhaust temperature.