Water connection device

A fluid source e.g. mains water supply is connected to a fluid user system e.g. a combination boiler by means including a non-return valve unit 1, a flow regulator 22 and pipework 21 for connecting the valve unit and flow regulator. The valve unit allows fluid flow to the fluid user system but prevents reverse fluid flow from the user system to the fluid source. The check valve unit 1 may have an outlet portion 3 permanently connected to the boiler and a conical inlet passage (16, Fig 2, not shown) in which a flexible pipe 21 may be held manually during top-up of the boiler. The unit 1 may include two identical valve stems 4, 5, 11. ...