I am trying to install a Breckwell P24I into my existing fireplace in my mobile home. The pre-manufactured chimney system is made by FMI. I was wanting to try to find an adapter from 3 inches off pellet stove to 8 inches going into the FMI chimney but only see the one for Simpson Duravent and was told it wouldn't work. Any ideas on how to make this work or do they make adapters to connect to the FMI chimneys? Thanks