I am looking at replacing the cleanout tee of my pellet stove chimney. The type of chimney is twick lock. This is a 3'' chimney, but outside diameter is 4''. I have just bought a part from Simpson duravent, but foud that the outside diameter is in fact 3 5/8''....thus not fitting on my system. Any idea of which company supplies pellet stove piping with a 4'' OD twist & lock chimney ?