How important is the gasket between the stove and pipe?

[Jason E]

Took my stovepipe off the back of my stove today to clean my ESP probe in my Harman P61A, hoping that it would solve my problem (will not operate properly in Room Temp mode). This was the first time I had the pipe off, as this is my first full season with it. Part of the insulation gasket ripped off with the pipe, and I honestly forgot to wedge it back in when putting the pipe back on.

Naturally, its there for a reason...is it critical I turn the stove off immediately, let it cool and re-insert this 1/3 piece of gasket missing? Thanks to anyone who can help...sorry for the relative "newbie" question!

 

[Delta-T]

replace the gasket. with that piece missing you are likely to get some smoke or soot leaking into the room and blown around by the distribution fan. New gasket is like $5. Do describe the problem you are having with room temp, maybe we can help.