What is a Closed system in domestic water?

A closed system in domestic water refers to a Plumbing setup where water circulates in a sealed loop, typically used in heating systems. In this system, water is heated and then circulated through radiators or underfloor heating, returning to the heater without being exposed to the outside environment. This design helps maintain consistent water temperature and pressure while minimizing water loss. Unlike an open system, a closed system does not allow for direct contact with atmospheric air, reducing issues like contamination and evaporation.