I have a Breckwell P23 insert that I just installed into my circa 1800 masonry fireplace using a 4" SS liner, approx. 25ft to termination. I have a chase cap on the terra cotta, and a standard SS chimney cap on top of that. Damper is set to "half", and this stove has been burning nicely right from the get go. Proper flame height and color, running it on 2 setting out of 5. Previous owner said he ran on 3 setting 24/7, maybe went to 4 on days in the single digits, and said he doesn't remember ever even trying level 5. If the stove is performing as good as this newbie thinks it is, should I be worrying at all about an OAK?