Opti-Mist
Platinum Member
The dampers that I think you're addressing go in the hot air duct that leads from your wood burner to the hot air distribution duct. The purpose is to prevent hot air generated by your oil burner from finding its way through the wood burner hot air outlet through the wood burner then to its cold air return and on to the cold air return of the oil burner. I hope that makes sense without a diagram. The intent is to preserve the integrity of your oil burner cold air return / hot air distribution system. The dampers for my system are to be installed in the hot air ducting at least 18 inches from the wood burner. The reason is that they contain rubber seals. I installed mine at the end of the first 24 inch hot air run.