You don't need to do anything! The best way to "turn off the Uuni" is to leave it to burn the remaining Pellets and cool naturally.

Top tips: 

  • If you're in a rush for Uuni to cool down, using protective gloves, remove the grate and dispose of the hot pellets. 
  • Try to time your last pellet top up before your last cook, that way there aren't as many pellets to burn through.