Good evening. I have noticed recently that I do not see secondary combustion on my Hearthstone Heritage which I purchased in Feb 2010, even after I have a good bed of coals and I reduce the air intake to low medium after charring the wood for 10 to 20 minutes. The baffle and air tubes look fine. I did use the open ash pan method of starting a few fires recently for less than a minute a time. Could this have damaged the secondary baffle in some unseen way which I why I do not see the secondary combustion burning from the tubes as I have in the past? Thanks for your help.