Some heat from another machine (5)
I believe the answer is:
therm
'some heat' is the definition.
(Therm is a unit of heat energy)
'from another machine' is the wordplay.
'from' indicates the answer is hidden within the clue.
'THERM' can be found hidden inside 'another machine'.
(Other definitions for therm that I've seen before include "Unit of measurement of heat" , "Unit of heat as in gas supply" , "Former gas supply unit" , "Unit of heat and gas measure" , "Unit of heat energy" .)