The high output coils in both the HF-85-XHO, with an 85-gallon tank, and the HF-115-XHO, with a 115-gallon tank, provide abundant hot water at a low operating cost. Hot water from any heating boiler is circulated through the coil inside the tank to heat all the water in the tank. The large counter flow heating coils are designed to promote more condensing when connected to high efficiency mod-con boilers. Smooth wall coils are used to minimize lime and sediment collection. Units can be easily banked together for applications with high water heating demands. Coils can take 300K to 495K BTU/hr. Tanks and coils are all 316 stainless steel construction.