Back puffing in my Appalachian 4N1 XL

[naugwalk]

Hi All,
I am new here. I have read many posts but this is my first time asking a question. I purchased an Appalachian 4N1 XL insert for my fireplace in OCT 2013. I have a ranch style home and it keeps it at about 72degrees when its 20 degrees outside. It runs fairly well but I have a few issues I am hoping someone here can steer me in the right direction.
When I light the stove there is no problem. I have the three air controls which I open all the way along with the flu damper. When the catalyst thermometer reaches about 700 degrees I shut the center air control and allow the gauge to reach between 800 – 900 degrees and I shut the flue damper. As soon as I do this the fire will die down to almost nothing. Then it will start back puffing like a locomotion which at this time I will open the flue damper again and the flames starts right up. I then shout the flue damper again but leaving it opened a crack and it will stop back puffing. I am using ash wood that is seasoned about a year. When I installed the chimney liner I wrapped it with the insulation and mesh. I should mention that my chimney is on an outside wall and is only 14 feet tall.
I was just wondering if anyone else was having problems and what might have been done to try and fix it? I was also wondering if by leaving my flue damper cracked a bit will it damage or do anything to the catalyst? Any help anyone can offer would be greatly appreciated.
Thank you,
Ed

 

[mellow]

try and shut it down in stages. I close off my shotgun air at around 400 then after a few minutes I will close the damper half way, then after a few more minutes I will reduce the air by half then close the damper fully, by now the cat should be near 1000, I then slowly reduce my main air down to fully closed then open it a smidge.
I have found if you shut it down to quick you will get back puffing.

if this doesn't fix the issue you might have draft and or wood issues.

 

[Backwoods Savage]

Welcome to the forum Ed.

Typically the back puffing is caused from lack of air so the fix is what you did; give it a little bit more air.

The chimney sounds okay if it is the right size. We have a SS chimney running totally on the outside of the house and have no problems with that. As for height, the manufacturer will typically recommend a minimum of height but one also needs to consider how many bends in the flue.

Leaving the flue damper cracked a bit should do no damage to the catalyst.

And mellow's advice on shutting the draft down in stages is wise. In our case, we usually first close down to anywhere from 35-50% draft. Our final setting will be about 20% draft. Some go even lower on the draft but each installation can vary so these numbers are not set in stove for sure.