The Arctic line of condensing boilers includes four new sizes: 1.5-million-, 2-million-, 2.5-million-, and 3-million-Btu input. In addition to certified efficiency of 95 percent, the boilers feature stainless-steel design, as well as a non-welded heat exchanger. Fully packed and knock-down configurations are available. With minimal water-side pressure drops and low minimum flows, Arctic accommodates variable-primary and primary-secondary piping designs. A 5:1 burner turndown is standard. Arctic is equipped with the Concert boiler control to save energy, optimize long-term efficiency, and integrate with all energy-management systems. It is intuitively icon-based and self-guiding, with USB data sharing.