Ea pele ke ho fepa metsi, ke hore, ho kenya metsi ka har'a boiler. Ka kakaretso, e na le pompo e khethehileng ho etsa hore mokhoa oa ho khelosa metsi o be bonolo le ho feta kapele. Ha metsi a kenngoa ka har'a boiler, hobane a nka mocheso o lokolloa ke ho tuka ha mafura, mouoane o nang le khatello e itseng, mocheso le bohloeki li hlaha. Hangata, ho eketsa metsi ho boiler ho tlameha ho feta mehato e meraro ea ho futhumatsa, e leng: phepelo ea metsi e futhumatsoa hore e be metsi a tletseng metsi; metsi a mangata aa futhumatsoa 'me a fetoha mouoane hore e be mouoane o tletseng; sehokelo.
Ka kakaretso, phepelo ea metsi ka har'a moqomo oa metsi e tlameha ho futhumatsoa pele ho economizer ho mocheso o itseng, ebe o romelloa moqomong ho kopanya le metsi a boiler, ebe o kenya potoloho ea potoloho ka ho theola, ebe metsi a futhumatsoa. ka riser Motsoako oa metsi a mouoane o hlahisoa ha o fihla mocheso oa saturation 'me karolo ea oona e fetoha mouoane; joale, ho itšetlehile ka phapang ea sekhahla pakeng tsa sepakapaka se phahamang le se theohang kapa pompo e qobelloang ea ho potoloha, motsoako oa metsi a mouoane o nyolohela ka har'a moqomo.
Moqomo ke sejana sa khatello ea cylindrical se amohelang metsi ho tsoa ho secheso sa mashala, se fanang ka metsi ho loop ea potoloho le ho isa mouoane o tletseng mocheso ho mocheso o phahameng, kahoo hape ke sehokelo lipakeng tsa lits'ebetso tse tharo tsa ho futhumatsa metsi, mouoane le ho futhumatsa haholo. Ka mor'a hore motsoako oa metsi a mouoane o arohane ka moqomong, metsi a kena ka har'a loop ea ho potoloha ka sefofane, ha mouoane o tletseng metsi o kena ka har'a tsamaiso ea mocheso o feteletseng 'me o kenngoa mouoane ka tekanyo e itseng ea mocheso o feteletseng.