Puffing back from Vigilant.

[Stoney Meadow Maple]

My Vigilant has been in the family since new in 1980 and i have heated my home with it since 2010, so i am familiar with it. Multiple rebuilds, the last probably 5 years ago, new door and top gaskets this fall. I try to maintain prolonged 350-375 stack temp in back burn, i am burning dry (2 years in my basement) oak. With the mild weather we are having it seems worse but have been having back puffing over the last few weeks, tonight it did it 5-6 times in an hour, I opened the secondary about half way, no change, opened the thermostat a little more, got hotter but ultimately did it again once it evened out. I have always hung a fence staple in the primary air intake to prevent this behavior before, keeps it from totally shutting down and sealing off the flapper. The fireback does have a crack, but no distortion, i plan to weld it this spring, still working on getting more made, but have been too busy to move forward with that endeavor. Currently i just loaded it and it’s hovering around 400 and behaving, but I suspect as soon as I go to bed I will smell the back puffing start again.
25’ of 6x10 stainless liner in a 4 flu chimney above it, 8” short adapter, elbow and thimble.
Any suggestions would be appreciated.

 

[fbelec]

i am going to say this by my experience with my defiant. i do the same thing but with a piece of copper wire on my primary air flapper. it helps keep the pipe thermometer up around 275 to 325. it drops a bit when in as the manual describes it as the long burn. mine puffed when i had a piece of punky wood in it for my last burn of the season a few years back. what happened is the secondary goes out and lights back up and when it does this it will find any little hole or crevice because when it lights up the air expands much faster than the chimney pipe can handle. so that crack or a space where air can get in makes it run hot enough to light back up and it also might go the other way and you will see it and smell it

 

[peakbagger]

My experience with a backpuffing Defiant for ten year was it was the operator. The temptation is to run long burns and control the fire with the thermostatic air damper. The problem is with good wood and bed of coals, the stove will create more gases than the combustion air can handle. VCs were designed to starve the firebox of air to some extent so that there would be secondary combustion in the secondary combustion chamber fed with heated air. Even with everything in original condition, they will puff back if loaded up before bed and then the air is cranked down to get a long burn. Its worse in shoulder seasons where the stove wants to run at higher heat output than is wanted in the house. It comes down to run shorter burns and give up on overnight burns. If you do add fresh wood, if anything open up the thermostatic air damper a bit.

 

[Stoney Meadow Maple]

I have been trying to run it in primary forna while by choking the damper down some to prevent serious overheating and allow the new wood to really get going, probably 5-600 stack temp, also hoping to get the elbow and transition to liner cleaned out. Next year i plan to switch to the other flu which is in good condition and should be a major improvement.

 

[Fred B. NJ]

My Vigilant has been in the family since new in 1980 and i have heated my home with it since 2010, so i am familiar with it. Multiple rebuilds, the last probably 5 years ago, new door and top gaskets this fall. I try to maintain prolonged 350-375 stack temp in back burn, i am burning dry (2 years in my basement) oak. With the mild weather we are having it seems worse but have been having back puffing over the last few weeks, tonight it did it 5-6 times in an hour, I opened the secondary about half way, no change, opened the thermostat a little more, got hotter but ultimately did it again once it evened out. I have always hung a fence staple in the primary air intake to prevent this behavior before, keeps it from totally shutting down and sealing off the flapper. The fireback does have a crack, but no distortion, i plan to weld it this spring, still working on getting more made, but have been too busy to move forward with that endeavor. Currently i just loaded it and it’s hovering around 400 and behaving, but I suspect as soon as I go to bed I will smell the back puffing start again.
25’ of 6x10 stainless liner in a 4 flu chimney above it, 8” short adapter, elbow and thimble.
Any suggestions would be appreciated.

View attachment 308079

I've been heating my homw with the Vigilant since 1981. I also had the back puffing issue. Mostly when the outside temp. was around freezing and no wind. I solved the problem by only burning the stove in updraft mode. Yes it burns the wood faster but never get back puffs anymore. Been using it this way for at least 30 years.

 

[Kwolt]

I’ll get puffing if I put a bunch of wood in and damp it down in the secondary burn mode. I’ve taken to putting less wood in and not laying it all horizontally. By laying a piece or two on the bed of coals and leaning a couple against the side so they don’t lay flat it reduces the amount of unburned gases at any one time and thus reduces puffing. It won’t burn as long this way but it will last the night and puffing hasn’t been as much of a problem.