ʻO ka valve butterfly, ka mea i ʻike nui ʻia he flap valve, he ʻano o ka valve hoʻoponopono i hoʻohana nui ʻia i nā ʻoihana like ʻole no ka hoʻomalu ʻana i ke kahe o nā wai. Aia i loko o kekahi mau mea nui, e like me ke kino valve, ke kumu valve, ka papa butterfly, a me ke apo sealing. Hana pū kēia mau mea e hōʻoia i ka hana kūpono a pololei o ka valve.