laynes69, how many cords are you burning each year with this new epa furnace? Also, I have an Englander 28-3500 attached to an outside chimney so I have also had a problem with smoke back up when starting a fire. My solution was to buy a cheap heat gun from Harbor Freight. I just pull the baffle forward, place the heat gun inside at the rear pointed up toward the flu and let it run for 5-10 minutes. Has worked great and no more smoke back up.