Hot matters to be dealt with? One can control the heat (10)
I believe the answer is:
thermostat
'one can control the heat' is the definition.
(device for controlling central heating)
'hot matters to be dealt with?' is the wordplay.
'to be dealt with?' indicates anagramming the letters (I've seen 'dealt with' mean this).
'hot'+'matters'='hotmatters'
'hotmatters' anagrammed gives 'THERMOSTAT'.
(Other definitions for thermostat that I've seen before include "Temperature regulator" , "Form of control" , "Heating device" , "Temperature controller" .)