RCB SERIES Commercial Wall-Hung Boiler is a compact building heat source that delivers reliable, energy-saving performance with ground-breaking features that outperform other boilers. Available in 301,000 Btu/h and 399,000 Btu/h models, the wall-hung boiler can provide heating to the building as well as connect to an indirect tank for domestic hot water production. The boiler features a stainless steel water tube heat exchanger with 97% thermal efficiency and 10:1 turndown ratio offers precise load tracking and energy savings. Combine up to 8 boilers on one system with integrated cascade logic that distributes runtimes equally for optimal application diversity.