Review the גמרא דף לח: “א”ר זריקא (seven lines from the top of the Amud) until the Mishna
Question:
What is the uncertainty in the case of פינה ממיחם למיחם (transferring the food to a different pot) whether it is permitted to return the second pot to the stove?
See רש”י “פינה
Learn תוס’ “פינה who asks a question from Gemara in the fourth perek.
See תוס’ ישנים answer from the רשב”א
Major Question:
Tosfos says there is a potential concern when one transfers hot food into a second pot that one might come to stoke the coals. How could there be a חשש שמא יחצה when we are dealing with a stove that is גרוף וקטום?
Learn ר”ן דף יז: דפי הריף “בעי רב אשי for an additional two answers
https://hebrewbooks.org/pdfpager.aspx?req=37953&st=&pgnum=584&hilite=
How are the two explanations of the Ran different than each other?
How are the two explanations of the Ran different than Tosfos?