A compact, gas-condensing boiler in a floor-standing design, the new CU3A is easy and simple to install in both new construction and retrofit applications. Multi-boiler installation with 8 boilers up to 1592 MBH. No primary/secondary piping required. Best-in-class components from Viessmann. Water cooled, stainless steel combustion chamber. MatriX radiant dome gas burner with 5:1 turndown ratio for efficiency of 95% AFUE and extremely clean combustion. High grade SA 240 316Ti stainless steel Inox-Crossal heat exchanger for maximum heat transfer and longevity. KW6B boiler and system control manages the entire heating system with precise temperature control. Lambda Pro easily adjusts to various fuel types and delivers optimum combustion efficiency.