The Condensing Gas Heating Boiler (NHB) is now available in four sizes: NHB-55, NHB-80, NHB-110 and NHB-150, with turndown ratios (TDR) respectively of 7:1, 10:1, 11:1 and 15:1. The 15:1 TDR in the NHB-150 is achieved with an advanced burner system. A key component to that efficiency is the newly developed dual Venturi gas delivery system. With a 95 percent AFUE rating, the NHBs carry Energy Star’s Most Efficient designation. Ideal for residential and light commercial use. Features include: large industry turndown ratios, which provide ease of installation with multiple smaller zones while maintaining high operational efficiencies; timed hydronic supply water boost feature; adjustable heat capacity and anti-cycle timer; freeze protection; pressure LWCO with manual reset; and more.