Heating and sanitary hot water temperature is input digitally.Gas quantity is adjusted automatically. *Heating water and sanitary hot water is divided and temperature can be set freely.Priority on sanitary hot water. *Constant temperature:it is designed special flow stabilized mount for sanitary hot water system. *Energy-saving:The thermal efficiency can reach above 90% by using intelligent room temperature controller. *Safety:With close gas supply and exhaust design,gets fresh air for combustion from outdoor and the waste gas is exhausted outdoor. *Environment friendly:The CO content in the waste gas is lower than 0.01%. *With close waterway design and built-in expansion water tank..It抯 hard to generate scale because the circulation hot water is totally isolated from atmospheric air.