older 70% efficiency furnaces use what kind of burner?\na heavy burner\na charged burner\nan in - shot…

older 70% efficiency furnaces use what kind of burner?\na heavy burner\na charged burner\nan in - shot burner\na ribbon burner

older 70% efficiency furnaces use what kind of burner?\na heavy burner\na charged burner\nan in - shot burner\na ribbon burner

Answer

Answer:

C. an in - shot burner

Brief Explanations:

Older 70% efficiency furnaces commonly use in - shot burners. Other options are not typical for such furnaces.