Last year I switched from an Avalon Olympic insert to a new VC Defiant stove, and had a lot of problems with back-puffing, over-firing, and any degree of controllability. In fact I posted a few threads on this forum seeking advice (thank you for all your responses and help!). In the 'off season', after some negotiation, the chimney sweep agreed to switch the existing 6 inch flex liner for a 8 inch stainless pipe for no fee... and what a difference it has made! Despite non-ideal conditions (i.e. not very cold outside temperatures), the stove is running like a charm. I've run it around 5 times so far with varying loads and varying air input settings without a hiccup.
A local dealer (who I did NOT purchase the stove from) came over to take a look at the installation before the switch to the 8 inch flue, and mentioned that that was probably the major cause of all the problems. He mentioned that the Defiant really needs the 8 inch flue to run properly (despite the literature which mentions that it can be downsized to a 6 inch if it is not run in 'fireplace' mode), and also mentioned that in general the flue should never be smaller than the stove flue attachment (whatever that's called). The fact that I have a short horizontal segment with two 90 degree bends and a half outside chimney might have exacerbated the problem (my chimney is about 22 feet tall). I do wonder how many folks that have had similar problems were also running on a 6 inch flue.
Well, I hope my luck continues (hope I haven't spoke too soon!). Maybe I'll go knock on some firewood!
Thanks again for everyone's help.
A local dealer (who I did NOT purchase the stove from) came over to take a look at the installation before the switch to the 8 inch flue, and mentioned that that was probably the major cause of all the problems. He mentioned that the Defiant really needs the 8 inch flue to run properly (despite the literature which mentions that it can be downsized to a 6 inch if it is not run in 'fireplace' mode), and also mentioned that in general the flue should never be smaller than the stove flue attachment (whatever that's called). The fact that I have a short horizontal segment with two 90 degree bends and a half outside chimney might have exacerbated the problem (my chimney is about 22 feet tall). I do wonder how many folks that have had similar problems were also running on a 6 inch flue.
Well, I hope my luck continues (hope I haven't spoke too soon!). Maybe I'll go knock on some firewood!
Thanks again for everyone's help.
