1 thing I don't understand

来源: 于 2011-12-21 12:28:05 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

The pressure of cold water and hot water are not the exactly same all the time. In my home, hot water has higher pressure than cold, because they come from different sources. If you make a loop from hot to cold circulation, eventually part of cold tube will become warm. It will burn more gas to maintain so.