Warmer steam iron here, failing, I am pressing down on it (9,6)

I believe the answer is:

immersion heater

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'warmer' is the definition.
Both the answer and definition are singular nouns.
Maybe there's a link between them I don't understand?

'steam iron here failing i am pressing down on it' is the wordplay.
'failing' indicates an anagram.
'i am pressing down' becomes 'im' (I can't explain this - if you can you should believe this answer much more).
'on it' says to put letters next to each other.
'steam'+'iron'+'here'='steamironhere'
'steamironhere' is an anagram of 'mersionheater'.
'mersionheater' put after 'im' is 'IMMERSION HEATER'.

Can you help me to learn more?

(Another definition for immersion heater that I've seen is " Electrical device".)

I've seen this clue in The Telegraph.

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