Amathuluzi okulawula izinga lokushisa, azaziwa nangokuthi ama-valve e-thermostatic, ayisicelo esijwayelekile sama-valve okulawula ukuhamba emkhakheni wokulawula izinga lokushisa. Umgomo wabo oyisisekelo uwukulawula isivinini sokungena somkhiqizo opholile (noma oshisayo) emishinini yokushintshanisa ukushisa, kumayunithi wokupholisa, noma kwezinye izinsiza ezisebenzisa ukushisa noma ukupholisa ukuze kulawulwe izinga lokushisa lokuphuma kwemishini. Lapho umthwalo ushintsha, isivinini sokuhamba silungiswa ngokushintsha ukuvulwa kwe-valve ukuze kususwe imiphumela yokushintsha komthwalo futhi kubuyiselwe izinga lokushisa kwenani elibekiwe.