Abstract: In one embodiment, a mains pressure valve has a body (10) and a main valve component (17) which is movable to effect opening and closing of the mains pressure valve. A flow controller (36) is disposed downstream of the main valve component and has a downstream end. At least one air vent (38) is provided downstream of the downstream end of the flow controller (36) and the vent is shielded from the downstream end of the flow controller (36). In another embodiment, there is a main chamber (12) within which the main valve component (17) moves, the main chamber having a control portion (40). A bypass passageway (13) has an upstream end (35) from the control portion (40) of the main chamber and a downstream end (46). A control valve (42) controls the flow through the by-pass passageway (13) to control the operation of the mains pressure valve. The downstream end (46) of the bypass passageway (13) is downstream of the flow controller (36).

Abstract: A mains pressure valve including a main chamber having an inlet chamber for fluid and an outlet for fluid, a non-return valve located downstream of the outlet and adapted to provide resistance to fluid flowing therethrough, a piston located in the main chamber which is movable into and out of sealing engagement with the outlet of the main chamber and which defines above it an upper portion of the main chamber and having an internal passageway which communicates between the upper portion of the main chamber and the inlet, a port in the upper portion which permits fluid to flow therethrough, and actuation control associated with the port to regulate the flow of fluid through the port. Upon actuation, fluid in the upper portion drains through the port, allowing the piston to rise and mains pressure fluid passes from the inlet chamber through main chamber and out discharge chamber.