Thursday, February 17, 2011

There is a single check/Y-strainer device plumbed in-line with a domestic hot water recirculation loop. Is this allowed?

Because you are dealing with domestic hot water, there is no requirement for backflow protection. If a backflow situation were to occur, you would only have potable domestic hot water going back into potable domestic cold water. The check valve is there simply to stop the hot water from backing up into the cold water.