My stove is over 20 years old. I ran into a problem last year when I start the stove( it's a manual start) when the door is open the draft fan runs it seems on high and the pellets start to burn and light as soon as I close the door from what I can hear the draft fan seem to be running very very slow you can hardly hear it, and the pellets want to go out, it's a very lazy fire. I remover the draft fan and cleaned it and there is nothing wrong with it. I checked the vacuum switch and it seems to work ok and the hose to it looks ok, even the high and low switches check ok. So I am not sure where to check or look for the problem. Once up and running it seems to be running right, but I still think there is something going on with the draft fan it seems I had to open the fresh air door more to get it to burn right. Suggestions or help will be appreciated. Thanks.