| 3.16 Filling a Sealed Water System Provision for filling the system at low level must be made. Three methods are shown in diagram 3.6. There must be no permanent connection to the mains water supply, even through a nonreturn valve. 3.17 Water Makeup Provision must be made for replacing water lost from the system. A make up vessel mounted above the highest point of the system and connected through a non-return valve to the system on the return side of either the hot water cylinder or heating system, see diagram 3.5. Alternatively provision for make up can be made by a filling loop. |