The M series condensing sections are optimized for use with any of the Reznor PreevA series of indirect fired HVAC systems. The M series can be used with other Reznor equipment with appropriate evaporator coils or with other brand air handlers when properly selected, matched and installed. The M series DX units utilize non-ozone depleting R-410A refrigerant. Dual circuits and scroll compressors are standard. The system is designed to achieve three stages of cooling. The cooling capacities range from 5 to 15 tons at full load (Minimum 2-5 tons). The three-stage (1/3, 2/3, 3/3) design makes the M series very efficient in overall seasonal energy use. This is due to the fact that while applications are generally sized to design conditions, a major portion of the total operation time is at conditions less than design. In addition to the added energy efficiency, other advantages include smoother load response across the range of operating conditions. Plus fewer off/on cycles, as compared to conventional single or two stage systems, results in reduced wear and tear on the system. Besides the superior operational design, the M series is also designed in an attractive cabinet, optimized for performance and overall size. The cabinet is constructed of G-90 coated material with a primer on the interior surfaces. A pre-coat off-white gloss finish is applied so the unit will stay cleaner, brighter and better looking for a long period of time. Complete access to all electric and compressor parts is provided to enhance installation and service ease.