I have a Harman P38 Pellet Stove (from 1997 mnufacture date), We just purchased a new home ( built 1900) and I am having a hard time finding a location suitable for the install. My best location is a corner in our middle room. Only 1 wall borders the outside of the home with 2 windows. I would like to install the stove in a corner but the only clearance to the vent pipe ( 3 inch simpson duravent) I am talking the wall thimble location is 12 inches to the CENTER of the chimney pipe and only 8 inches to the edge of the wall thimble. Harman suggests a 12" clearance to the vent....Is that measurement from the edge of the wall thimble or the center of the pipe or edge of the pipe? (from a corner of the wall). Thanks.