You better keep the heat on low or you'll burn your pancakes.
If you keep the heat on high, you'll burn your pancakes, so you better turn down the heat.
ーYou better keep the heat on low or you'll burn your pancakes.
「火を弱めたままにしないとパンケーキが焦げちゃうよ」
to keep the heat on low で「火を弱火のままにする」
to burn で「焦がす」
ーIf you keep the heat on high, you'll burn your pancakes, so you better turn down the heat.
「強火のままだとパンケーキを焦がすから、火を弱めた方がいいよ」
to keep the heat on high で「火を強火のままにする」
to turn down the heat で「火を弱める・弱火にする」
ご参考まで！
カナダ 
