Turn aside to maintain temperature (5)
I believe the answer is:
avert
'turn aside' is the definition.
(thesaurus)
'maintain temperature' is the wordplay.
'maintain' becomes 'aver' (averring is a kind of maintaining).
'temperature' becomes 't' (abbreviation).
'aver'+'t'='AVERT'
'to' acts as a link.
(Other definitions for avert that I've seen before include "Deflect away" , "Turn away, prevent" , "Prevent from occurring" , "Turn aside or ward off" , "Prevent, ward off" .)