pilot burner vs pilot light

pilot burner

noun
  • Synonym of pilot light (“persistent flame to ignite gas”) 

pilot light

noun
  • A small, persistent flame used to ignite gas. 

  • A small telltale lamp on a dynamo or battery circuit whose brightness indicates the voltage of the current. 

How often have the words pilot burner and pilot light occurred in a corpus of books? (source: Google Ngram Viewer )