Emazingeni okushisa aphansi, i-CO2 inomfutho wegesi ophansi. Amathangi kufanele aklanywe ukuthi amelane nokushintsha kwengcindezi emazingeni okushisa aphansi kuyilapho kugwenywa izinguquko ezisheshayo phakathi koketshezi negesi. Njengoba izinga lokushisa likhuphuka, ingcindezi yegesi ye-CO2 iyanda, okudala umthwalo omkhulu wengcindezi ethangini. Imiklamo yamathangi yamazinga okushisa aphezulu idinga ukucatshangelwa komklamo wokuphepha komkhumbi wengcindezi eyengeziwe, okuhlanganisa ama-valve okulawula ukucindezela kanye nama-valve okuphepha.