No leads on the water boiler? (6)
I believe the answer is:
heater
'the water boiler?' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's a link between them I don't understand?
'no leads on' is the wordplay.
I cannot quite understand how this works, but
'on' could be 'at' (I've seen this in other clues) and 'at' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for heater that I've seen before include "Source of warmth; gun" , "Radiator" , "fire" , "Room warmer" , "Warming device" .)