Rinnai INFINITY HD56K – External Gas Continuous Flow Hot Water HeaterRinnai INFINITY HD56K External Gas Continuous Flow Hot Water Heater Natural Gas or LPG Commercial & Residential 56 kW Output All genuine Rinnai accessories for this unit are available to order on request. The Rinnai INFINITY HD56K is a high performance, external continuous flow hot water system designed for large homes, commercial buildings, and high demand applications. With up to 37 L min of hot water and a powerful 56 kW output, it delivers