Recently purchased new Encore Flexburn stove. The stove has a round flange for connecting the stove pipe to, but it is kind of "shouldered" and the stove pipe does not seal well around it. It is not the older oval style flue. VC suggested part 0001860, but that part is for the older oval flue to round pipe. Is there a part or method for sealing this connection? I used duravent double wall pipe. Also, I purchased the duravent flue adapter piece but it is not of any use. Seems like the ideal piece would be made by VC for this particular stove. Any help is appreciated.