Maximum liner in 7x7" ID clay lined flue? 5" , 5.5"?

[jayVI]

Hello,

Installer is recommending installing a 5" liner in our 7x7" ID clay lined flue. We have a 15' chimney that is internal to the house. Would a 5.5" fit? The insert is a Pacific Energy Neo 1.6 , which has 5.5" or 6" in the manual. Will the 5" cause issues? The installer(WETT certified) claims it will be fine.

Thanks!

 

[Supersurvey]

I have a similar situation. Hampton HI200. Takes a 6 or 5.5 inch. I figure a 5 inch will still be safer than my professionally installed 6 inch that was smashed will a sledge hammer by my professional installer to fit my 7x11, 16 foot tall chimney. If I only knew then what I know now.