to prevent backflow.

Causes

Backflow occurs for one of two reasons, either back pressure or back siphonage.

Back pressure is the result of a higher pressure in the system than in its supply, i.e. the system pressure has been increased by some means. This may occur in unvented heating systems, where thermal expansion increases the pressure.

Back siphonage is the result of supply pressure being lowered below that of the system. This may occur when a supply is interrupted

1.Previous
3.Next