operating info

[rsting]

Hi, I've got a mama bear, six inch pipe with damper in pipe. I've got two questions on proper use.
When starting the stove, when it starts burning good, iI get a lot of puffing out the front vents. Sounds like a steam locomotive. I'lleven get some flame puffing out of them. Normal?
On the opposite end, banking the stove for the night. I fill with wood, close the damper, and leave the front vents a little less than half open. Always burns out completely. I tried closing the front vents off, and it cooked the creosote out of the wood. Dripped out of the pipe.
One more, is it better to leave the pipe damper partly open and regulate with the front vents, or just the opposite?
Thanks, Russ

 

[woodburner44]

The same type of puffing or choo-chooing occurs with my outdoor boiler when starting up a new load of wood. I milk the inlet air vent closed just until the puffing quits. I am going to guess you have a long flue. The puffing seems to have become worse after I installed a 20' stainless flue.
Have you tried closing the inlet air vents a little at a time until the puffing just stops? It might help.

 

[coaly]

My guess is a larger than 6 inch cool chimney......... Usually a chimney issue.
What size diameter is your chimney flue? height? Insulated flue or masonry.

A couple things can make it chuff. A fast, almost sputter can be too dry of wood that can gassify rapidly with too much volatile gasses. (like starting with cardboard) Older super dry wood can burn fast and not have a pile of coals in the morning.
A cool chimney, or one larger than the stove outlet requires more heat for the proper draft.
Rising gasses lighter than air cool near the top and stall or drop. The low pressure created in the flue from the lighter rising gasses no longer puts the firebox in a vacuum for atmospheric pressure to push into the intakes. Expanding gasses go both out the exhaust and out the intake until the chimney rises enough for everything to rise the proper direction. The cycle repeats..... You can try cracking a window or door on that level to see if it makes a difference. It's all about getting higher air pressure to the stove intakes than out the exhaust.

The flue diameter and height can determine how fast the chuffing since it's all about how much heated air is rising and falling. How fast is the chuffing? It can vary from every half second to every 30 seconds......

Technically a stove considered air-tight can be controlled with intake air and not controlled by the outlet or flue damper. The manual does not require a damper on the single door stoves, but when the manual was written, flues were masonry and large for fireplaces or commonly 7 inch square. So they needed a full 6 inch opening outlet wide open. Today it's more efficient to install an insulated chimney or insulated liner that stays hotter inside having more pressure differential, or lower pressure inside. Then, many times a damper reduces the stronger draft the more efficient chimney creates.
The double door stoves require a damper in the manual due to open door burning with screen in place. This becomes your only control with doors open.
I personally close the damper when starting with kindling until the roar stops. This way it gets all the air it needs, but holds more heat in the stove to ignite the larger pieces. Closing the intakes does the same thing by depriving oxygen, which you don't want to do until up to temp.

There is no "half , or less than half " setting on a Fisher. (maybe you mean a half turn?) Spin the caps open a few turns when lighting. Close down to about a turn or so once established. Then set to output you need for comfortable heating. That can be cracked to a full turn or more. No one can tell you damper operation since chimney size and height, outside temperature and air pressure (storms and elevation) affect the damper position required at the time.
You should have a magnetic thermometer on the pipe to know what temp the pipe is entering flue. With good wood, you should have a good pile of coals in the morning depending on air adjustment.

Information on back puffing; (broken link removed)

 

[coaly]

Wood doesn't contain creosote that cooks out. Burning too low by closing intakes condenses water vapor from combustion in the chimney flue below 250* and that is the fluid that leaks out of joints if they are put together backwards. It can leak from sectional elbows as well. Joints should be male end down to keep any liquid inside the pipe and run back to be consumed in the stove. Smoke particles in the flue stick to the walls when condensing and forms creosote.

 

[rsting]

OK, I stand corrected on things. You did help me figure my problems though. Puffing, cold flue very old, dry wood.
On banking, I'm leaving the air intake open way too much! Operating it open too much also. When I said half, I meant I was leaving it half way between wide open and closed. I don't know how many turns total that is, but its way more than you said.
This is being used as a shop stove, in a metal building, with a steel pipe chimney. Cold flue is just a fact of life, but I'll cut back on the air flow, and the old wood is just about gone.
Thanks for all your help!

 

[coaly]

Yeah, getting terminology right is a big part of understanding a problem.
I think I spin them open 2 or 3 turns when starting. Once up to temp, I go by how many fins open. So I close it and note where one fin is. Then open it by counting fins. You get to know by the outside temp how many to keep it open. Some people go by the space behind the cap that it's open, like 1/8, 1/4 or 1//2 inch.
I assume you mean you have an insulated stainless double or triple wall chimney. If you mean single wall connector pipe used to connect a stove to the chimney, you have NO chimney.
Mix that old wood with some fresher stuff.