A method of operating a hydrogen dispensing unit comprising: dispensing hydrogen from a supply vessel to a receiving vessel (118 or 218) via the hydrogen dispensing unit, the hydrogen dispensing unit comprising a heat exchanger to cool the hydrogen prior to the hydrogen being dispensed into the receiving vessel (118 or 218), said dispensing continuing until a target quantity of hydrogen is dispensed and thereupon terminating said dispensing; wherein upon terminating said dispensing, a first quantity of hydrogen is trapped within a first one or more conduits (130, 132, 232, 233), the first one or more conduits operatively connecting a plurality of valves, the plurality of valves including a control valve and a block valve (108 or 208), said first quantity of hydrogen being trapped upon closing said plurality of valves, at least a portion of the first quantity of hydrogen having been cooled in said heat exchanger, the first quantity of hydrogen exerting a pressure in the first one or more conduits (130, 132, 232, 233); measuring the pressure of the first quantity of hydrogen in the first one or more conduits (130, 132); opening and subsequently closing the block valve (108 or 208) when the pressure of the first quantity of hydrogen equals or exceeds a selected pressure thereby removing a fraction of the first quantity of hydrogen from the first one or more conduits (130, 132, 232, 233) and transferring the fraction of the first quantity to a second one or more conduits (134, 136 or 234, 236), the second one or more conduits (134, 136 or 234, 236) operatively connected to the block valve (108 or 208) and a bleed valve (114 or 214); and opening and subsequently closing the bleed valve (114 or 214) thereby discharging a first quantity of vented hydrogen from the second one or more conduits (134, 136 or 234236). dispensing hydrogen from a supply vessel to a receiving vessel (118 or 218) via the hydrogen dispensing unit, the hydrogen dispensing unit comprising a heat exchanger to cool the hydrogen prior to the hydrogen being dispensed into the receiving vessel (118 or 218), said dispensing continuing until a target quantity of hydrogen is dispensed and thereupon terminating said dispensing; wherein upon terminating said dispensing, a first quantity of hydrogen is trapped within a first one or more conduits (130, 132, 232, 233), the first one or more conduits operatively connecting a plurality of valves, the plurality of valves including a control valve and a block valve (108 or 208), said first quantity of hydrogen being trapped upon closing said plurality of valves, at least a portion of the first quantity of hydrogen having been cooled in said heat exchanger, the first quantity of hydrogen exerting a pressure in the first one or more conduits (130, 132, 232, 233); measuring the pressure of the first quantity of hydrogen in the first one or more conduits (130, 132); opening and subsequently closing the block valve (108 or 208) when the pressure of the first quantity of hydrogen equals or exceeds a selected pressure thereby removing a fraction of the first quantity of hydrogen from the first one or more conduits (130, 132, 232, 233) and transferring the fraction of the first quantity to a second one or more conduits (134, 136 or 234, 236), the second one or more conduits (134, 136 or 234, 236) operatively connected to the block valve (108 or 208) and a bleed valve (114 or 214); and opening and subsequently closing the bleed valve (114 or 214) thereby discharging a first quantity of vented hydrogen from the second one or more conduits (134, 136 or 234236).