A method of using a valve, wherein said valve comprises: a housing having an inlet port, a liquid outlet port, an inlet chamber, a pressure responsive closing mechanism disposed between said inlet port and said liquid outlet port and configured for selectively opening a liquid flow path therebetween, a control chamber in fluid communication with said inlet chamber via a fluid passage (54, 64), a gas operated valve in fluid communication with said control chamber and with an outlet aperture, wherein said closing mechanism is configured to be displaced into an open position to permit liquid flow along said flow path between said inlet port and said liquid outlet port; and wherein said fluid passage (54, 64) comprises a controlled closing system for controlling opening and closing of said fluid passage (54, 64), said controlled closing system comprising a seal movable with respect to and sealable against an opening of said fluid passage (54, 64); and comprising a mode of operation wherein said seal does not seal against said fluid passage (54, 64), said pressure responsive closing mechanism seals against said inlet port, and said gas operated valve does not seal against said outlet aperture, so that gas entering said inlet port of the valve 10 can rise and flow past said seal through said fluid passage (54, 64), and flow out said outlet aperture, and comprising another mode of operation wherein said pressure responsive closing mechanism seals said inlet port, and as soon as fluid cannot flow anymore to said liquid outlet port, said seal immediately drops to open said fluid passage (54, 64). wherein said valve comprises: a housing having an inlet port, a liquid outlet port, an inlet chamber, a pressure responsive closing mechanism disposed between said inlet port and said liquid outlet port and configured for selectively opening a liquid flow path therebetween, a control chamber in fluid communication with said inlet chamber via a fluid passage (54, 64), a gas operated valve in fluid communication with said control chamber and with an outlet aperture, wherein said closing mechanism is configured to be displaced into an open position to permit liquid flow along said flow path between said inlet port and said liquid outlet port; and wherein said fluid passage (54, 64) comprises a controlled closing system for controlling opening and closing of said fluid passage (54, 64), said controlled closing system comprising a seal movable with respect to and sealable against an opening of said fluid passage (54, 64); and comprising a mode of operation wherein said seal does not seal against said fluid passage (54, 64), said pressure responsive closing mechanism seals against said inlet port, and said gas operated valve does not seal against said outlet aperture, so that gas entering said inlet port of the valve 10 can rise and flow past said seal through said fluid passage (54, 64), and flow out said outlet aperture, and comprising another mode of operation wherein said pressure responsive closing mechanism seals said inlet port, and as soon as fluid cannot flow anymore to said liquid outlet port, said seal immediately drops to open said fluid passage (54, 64).