Papa Bear, no stovepipe damper

[Dr_1400]

Hello,

This forum is fantastic. Thanks to all who contribute. I'm hoping to get some advice on tweaking my setup. I have a log cabin in the Adirondacks that we use primarily on weekends. A Papa Bear is our primary heat source, sitting in the middle of the room. We've got about 15 total feet of pipe, with the lowest 6 or so being single wall inside the main room, and the rest being double wall up through the loft space and then through the roof. Aside from the elbow coming out of the back of the stove, it's a straight run with no angles.

The pipe has no damper. We have a stove top thermometer that we use to make sure we're out of the "creosote zone" and check the single wall pipe where it meets the ceiling with an IR thermometer. I've been sweeping the pipe from the roof regularly, and we don't produce much creosote at all. Because of that, I'm hesitant to change anything. At the same time, we're burning through wood really quickly, and I'm wondering if we could slow our consumption and increase our efficiency while not adding any creosote to the mix.

Related to this, I've been interested to read about how far open people run their draft caps. If we go down to 1/2 turn like many seem to do, we don't produce enough heat to keep the cabin warm (all the heat going up and out through the pipe?). So we end up running the stove with a lot of air on the fire (open at least a couple turns, usually).

Coaly, I know you've advocated a stove pipe damper to slow down a chimney fire, and also a baffle plate.

My question is, would you all recommend we:
-change nothing
-install both stove pipe damper and baffle plate
-if we were only going to do one, which one?

Any feedback is appreciated.

 

[coaly]

Both!
Install a baffle plate without question. You can make a big one with the good draft and chimney you have. I would angle it upward at front and make it long enough to reach from back to about 1/2 the way across the front lower top towards the door. Newer stoves bring the baffle right up close to the front door and work fine with your type chimney. Keep the square inch area the smoke travels the same size as the 6 inch round square area. No smaller than 28.26 square inches. You can always drop it lower in front to adjust for more to go out. You’ll find the lower top gets hotter than the back. It won’t have the high temp spikes up the pipe either.

The baffle adds a little resistance within the firebox. A flue damper is a variable resistance. I have both in my cabin with a Mama Bear, elbow like yours and straight up about that same height. The damper is good if you fire it with lots of paper and cardboard with small kindling and it roars up the stack. That’s when you want to keep more heat in the stove to preheat larger wood getting it going. So I tilt it just enough to stop the roar. Once up to temp, with larger wood it can usually be left open unless extremely cold. With no baffle, more damper is needed. Normally never than 1/2. If you don’t make a baffle right away, the flue damper is quick and easy and variable, so wide open is like what you have. You need to be able to fine tune the draft for different conditions. Low pressure moving over with not too cold outside will not need any damper at all. As conditions and wood changes m, you need that variable resistance to control the draft better than wide open all the time.

A flue damper left open is like not having one at all, so usually you can close it slightly when burning clean without issue. Just don’t over use it unless you need to slow the fire on an extremely cold day. It may not need any damper when warmer since draft is low without a large temperature difference inside and out of chimney. Colder days it may draft too strong needing to be slowed down. As you’ve probably read, a flue damper is a chimney control that slows the velocity of rising gasses in chimney. This reduces draft reducing how much air comes in. Moisture content and wood species makes a big difference of how much air you need to give it too.

I find with good dry wood, over one turn burns too hot unless cooking or heating water. Space heating does good for me between 1/2 and 1 turn each. That is a Mama in less than 1000 sf with log walls. Once burning more than a day, wall logs are like a heat sink that radiate back into the cabin, so I have to turn it down from 1/2 to 1/4 turn. I never tried it without a baffle in the cabin.

Just watch your pipe temp as you’re doing. The surface temp is about half the actual flue gas temperature. Then guess at cooling in the flue to top. Triple wall cools more than double wall.

 

[Dr_1400]

Thank you, Coaly. Your Fisher knowledge is unsurpassed.

Our cabins sound similar. We're in year 3 and slowly getting ahead on good, dry wood. Everything now is at least a year seasoned, which makes me less hesitant to add some resistance. I believe we're now cutting for 2023-2024 so moving forward we should be in a good position. Being able to slow this burn down would be of great assistance in getting ahead!

On the baffle plate - do you (or anyone else reading) have dimensions for the Papa Bear plate addition? Ours is the 4-fin draft cap type, in the event that and the 5-fin models were different dimensions. I'd like to get something cut here in town before we go back to the cabin. Is 5/16" steel best?

The baffle plate is appealing as a first step, as it could be (I assume) easily set inside once cut to size.

 

[coaly]

Notice I start with a baffle first. This reduces smoke particles by a lot, so reducing flue temp doesn’t have as many particles to stick to be able to create as much creosote.

 

[Dr_1400]

Notice I start with a baffle first. This reduces smoke particles by a lot, so reducing flue temp doesn’t have as many particles to stick to be able to create as much creosote.

Got it, thanks Coaly. In reading old threads after I posted, I found that even amongst Papa Bear models the plate size may not be universal. I’ll cut cardboard to make a template next time I’m there.

Just to confirm, is the plate resting on the red arrows in the pics? With the end towards the door resting either on added firebrick or tabs welded to the plate? (Please excuse dirty stove, have since learned via this forum to burn only dry wood!)

 

[coaly]

That’s exactly where you set the side bricks to support the front of plate. 5/16 is best. Stoves should measure the same, but some fabricators had favorite ways of building them, so they can vary. Cardboard template is the best. When sat on bricks, a piece of angle iron can be welded or bolted at the side edges facing downward to hold bricks tight against side walls. I wedge a piece of firewood across the stove to hold bricks in position against walls while setting the template and baffle plate in position.

Yes, the back sets on the horizontal plate. If there is not enough space under pipe to tilt upward you may have to notch the plate at rear to get it to slide back to the rear wall. Your template will show you that if you double up the cardboard to give you an idea of how tight it will fit under pipe. Most rear plates sag down giving enough room to slide the baffle back to stove rear wall. The bricks supporting yours are not normally there.