turn (something) up
Definition: to increase the volume or power produced by a machine. (Opposite: turn (something) down)
(This phrasal verb has more than one meaning)
E.g.1: Could you turn the TV up? I can’t hear it.
E.g.2: I’ve turned up the heating because it’s a little cold in here.
This phrasal verb can be separated. (E.g. 1)