can someone help me , I have a napoleon 1400 , and have been using it for about five years . I burn it from mid October thru mid March 24/7. THIS year I noticed a difference in the way it burned the wood , not as good. I have not done anything to this stove except clean the flue twice a year. I do have a couple cracked bricks and the baffles at the top are a little distorted , but still in one piece. I did remove the stainless steal manifold on top and there wasn't a gasket behind it, do I really need a gasket for this manifold, and if so what does it do? it seems like the secondary air chamber is not working right, can it get clogged ? this stove worked great for all these years and just went south for the winter, not a good time to go south .