Room with central heating control light (7)
I believe the answer is:
chamber
'room' is the definition.
(chamber is a kind of room)
'with central heating control light' is the wordplay.
'with' means one lot of letters go next to another.
'central heating' becomes 'ch'.
'control light' becomes 'amber' (I can't explain this - if you can you should give a lot more credence to this answer).
'ch' put next to 'amber' is 'CHAMBER'.
Can you help me to learn more?
(Other definitions for chamber that I've seen before include "Official room" , "Judicial assembly - room" , "Bedroom" , "vault" , "Enclosed cavity, part of gun" .)