I just finished repairing/rebuilding several parts on my Winterwarm 1280 after 23 years of (mostly) faithful service. All went well (new catalytic converter, new left and right throats, bar grate, front glass etc) but I am still unable to get the damper to fully/firmly close. It swings free and well but just doesn't get all the way closed. Anyone been in that part of this stove insert and figured out how it works or gets hung up? Thanks.