Wonke ama-valve okuhlola avivinywa ngokwefekthri ukusebenza kwawo ngokuqhekeka nokuvala kabusha ngomtshina wokuvuza okuwuketshezi.Wonke ama-valve okuhlola ajikeleziswa izikhathi eziyisithupha ngaphambi kokuhlolwa.Wonke ama-valve ayahlolwa ukuze kuqinisekiswe ukuthi ayavala phakathi nemizuzwana emi-5 ngomfutho ofanele wokuvala kabusha.