expression, ichidan verb
put on the fire; heat on a fire
Idiomatic expression meaning to place a pot, pan, or kettle over a heat source for cooking or boiling. Often used with cooking vessels.
See also: 掛ける
鍋を火にかけて、お湯を沸かしてください。
Put the pot on the fire and boil some water, please.
フライパンを火にかけてから油を入れる。
I heat the frying pan on the fire and then add oil.