Inefficient flue design?


New Member
Jul 7, 2019
Hi all,

I noticed the flue on my Piazzetta pellet fire has a little section that protrudes down over the outlet (about a quarter of the way) where the exhaust/outlet of the pellet fire meets the rest of the flue. The sketch below shows this better than I can explain...

Screen Shot 2019-07-21 at 7.27.49 pm.png

It only overlaps by about 1.5cm – so there's still plenty of airflow underneath, but I was wondering if this kind of design might cause turbulence in the flue and create a little back-pressure or other strange behaviour? (such as intermittent failed lighting or black soot on the glass?). Or would it not really make any difference with such low pressures? Curious to see what others think.

As the flue has been riveted and silicon sealed, it's not that easy for me to open it up and trim away the part that protrudes down...

Cheers, Kim :)
Last edited:
Nov 20, 2018
The bit at the bottom is to give access for cleaning the flue. It will collect ash, which should be removed periodically. When you do your major clean after each ton of pellets would be a good time to take care of that.