Chotenthetsera chomiza chimatenthetsa madzi mkati mwake.Pano, pali chinthu chotenthetsera chomwe chimamizidwa m'madzi, ndipo mphamvu yamagetsi yamphamvu imadutsamo yomwe imayambitsa kutentha madzi omwe akukumana nawo.
Chowotcha chomiza ndi chotenthetsera chamadzi chamagetsi chomwe chimakhala mkati mwa silinda yamadzi otentha.Zimakhala ngati ketulo, pogwiritsa ntchito chowotcha chamagetsi (chomwe chimawoneka ngati chitsulo chozungulira kapena koyilo) kutenthetsa madzi ozungulira.
Ma heaters a WNH amapangidwa makamaka kuti amizidwe mwachindunji muzamadzimadzi monga madzi, mafuta, zosungunulira ndi njira zothetsera, zinthu zosungunuka komanso mpweya ndi mpweya.Mwa kupanga kutentha konse mkati mwamadzimadzi kapena njira, zotenthetserazi zimakhala ndi mphamvu zokwanira 100 peresenti.Ma heaters osunthikawa amathanso kupangidwa ndikupangidwa kukhala ma geometries osiyanasiyana kuti azitenthetsera mowala ndikulumikizana ndi ntchito zotenthetsera pamwamba.