Adding 5" reducer to lower draft?

[Amin1992]

Hey all. Saw this posted in another thread I was perusing and got curious.

I have a very difficult time controlling my wood stove. Once the draft and fire get going, lowering the air all the way does nothing.

I read that some people put a 5" reducer on the top of their liner to counter overdrafting.

Does that work? I'm thinking of grabbing something like this
(broken link removed)

What do you guys think? I'm thinking of just attaching this up top and seeing how it affects draft.

Would it work? Any concerns in doing it? Thanks!

 

[begreen]

This would be similar to adding a key damper, but more permanent. It might adversely affect mild weather burning.
Have you tried all other measures like turning down the air sooner and more aggressively, loading thicker splits, adding 1 or even 2 key dampers to the stovepipe?

 

[bholler]

Hey all. Saw this posted in another thread I was perusing and got curious.

I have a very difficult time controlling my wood stove. Once the draft and fire get going, lowering the air all the way does nothing.

I read that some people put a 5" reducer on the top of their liner to counter overdrafting.

Does that work? I'm thinking of grabbing something like this
(broken link removed)

What do you guys think? I'm thinking of just attaching this up top and seeing how it affects draft.

Would it work? Any concerns in doing it? Thanks!

That is a last resort in my opinion. What draft do you have?

 

[Amin1992]

This would be similar to adding a key damper, but more permanent. It might adversely affect mild weather burning.
Have you tried all other measures like turning down the air sooner and more aggressively, loading thicker splits, adding 1 or even 2 key dampers to the stovepipe?

I see. If it doesn't work I could easily go to the roof and remove this from the cap, so not too permanent. I've tried everything with no luck so far. How much would it affect draft you think? And I can't add a key damper because it's an insert.

That is a last resort in my opinion. What draft do you have?

I don't have a way to measure but it seems super strong. Thanks for replying.

 

[bholler]

I see. If it doesn't work I could easily go to the roof and remove this from the cap, so not too permanent. I've tried everything with no luck so far. How much would it affect draft you think? And I can't add a key damper because it's an insert.



I don't have a way to measure but it seems super strong. Thanks for replying.

How long have you been burning the insert? What have you tried?

 

[JimBear]

As @begreen mentioned: What size of splits/wood chunks are you burning?

 

[Amin1992]

Oh geez, where to start. I feel like I've tried everything! First year with my own stove here in this house - only had family's before.

I've tried different wood, from 4 year old oak, to 1 year old walnut, to 2x4s, year old maple... List goes on.

I've done N-S and E-W orientation. Stuffed the box and tried just a few splits.

I've done 3" thick, 6" thick, and 8" thick splits.

I've shut down the air slowly, and quickly. Typically I can reload with the air control all the way down and it still reignites.

I love the stove but I hate not being able to control it, and I never get lazy, ghostly secondary burns anymore. The room shoots up to 80+F then the fire dies down quickly. The draft is so strong I can hear it sucking in, and the door shuts itself if open, even with a small fire and air down.

 

[begreen]

It won't hurt to try the reducer. Hope it helps. A key damper can be added to some insert installations. It's a bit of work but has been done with an extension to bring the handle out through a hole in the surround. There were some posts on this a couple of years ago.

 

[Amin1992]

Thanks, I'll give it a shot. Could one like this work? Or should it strictly be stainless steel?

(broken link removed to https://www.acehardware.com/departments/heating-and-cooling/chimney-and-flue/stove-pipe-reducers/48683?store=14082&gclid=CjwKCAiAudD_BRBXEiwAudakX31tRI66-iPiqkrVM89-NVtGuOvqzdy3GfbQjsv6QHsOoYOsOxXkxBoCvk0QAvD_BwE&gclsrc=aw.ds)

 

[begreen]

It should be stainless. That piece wouldn't last long at all outdoors.
(broken link removed)

 

[Amin1992]

Thanks, I'll order stainless!

Out of curiosity, how much clearance is needed between the end of the liner and the cap? I guess I'm asking , how large an opening is required?

Just want to make sure this reducer will fit. I also wonder if my opening being so large contributes to my large draft...

 

[ABMax24]

I think you're going to be disappointed with the results. 6" to 5" is only about a 30% reduction in pipe area. My factory made key damper is about an 80% reduction in area.

 

[brenndatomu]

Pic of above the insert?
Might be able to squeak a key damper in there...best solution if you can pull it off.
If you don't have room under your chimney cap for the restrictor (and you probably don't) you can just get a stove pipe cap and cut a 5" hole in it to test your restrictor idea...its just steel, but good enough for testing purposes...can get a stainless one later if it actually works...

Imperial 6 in. D Steel Crimped Stove Pipe Cap Mfr# BM0151 - Ace Hardware

Close off the end of your stove pipe assembled tee with this Imperial 6-in End Cap. It features a crimped design that makes it suitable for installation on the non-crimped end of the assembled tee and allows for easy access to enable pipe inspection and cleaning. It's designed for durability and...

www.acehardware.com

 

[john26]

If your cap is easy to access maybe you you could attach a stainless L bracket on the side of your flue pipe then attach a stainless plate to the bracket that would slide making it adjustable. That way you could experiment with it and if made small enough you cap would fit over it. Basically it would be like a top mount damper.

 

[mellow]

I have said in the past against much backlash that I would try an offset box first before a key damper to reduce draft for an insert install. The offset box is to be stainless.

Off-Set Box & Insert Adapter for Flexible Chimney Liner Systems - Rockford Chimney

Shop Adapters: A two-piece adapter for fireplace inserts. Off-set box allows you to adjust the insert front and back from inside firebox. Free shipping.

www.rockfordchimneysupply.com

 

[john26]

I have said in the past against much backlash that I would try an offset box first before a key damper to reduce draft for an insert install. The offset box is to be stainless.

Not going to get a soot eater through that.

 

[begreen]

There isn't enough room for the reducer with that cap. It will need to be changed also. You might want to wait for a clear weather period and try a reducer as a test before committing. If just for testing, the cheap Imperial reducer could temporarily be used without any cap.

Did you find the thead(s) about installing a key damper in an insert flue?

Is that a 6" flue at the top? It looks larger, but it might just be the drill is smaller than mine.

 

[Amin1992]

Yes I'm thinking of doing that here soon. I did order a reducer just in case to play with - $30 versus $15 for the cheap cap so I figured might as well.

I could not find the thread on the key damper in an insert, do you know where it is by chance? though not sure if I could get that to work on my setup.

And yes, 6" but ovalized a bit that may be why it looks wider from the photo's perspective!

I just got thinking: what if I took a spare firebrick and stuck it on top of the baffle blanket, under the liner inlet, inside the stove? Could that help restrict the the opening a bit, or is that not a good idea?

 

[john26]

I just did this on my Lopi freedom. I tried 1 centered then 2 bricks in the opening above the door where the flue gases exit the firebox into the top of the stove. I had minimal primary air control is a little touchier but still seems like a fast hot burn. I am getting ready to put new gaskets on the door before I try anything else.

 

[Amin1992]

Hey thanks for sharing. Bummer it didnt work for you. Have you tried a reducer up top like im thinking of?

 

[begreen]

Hey thanks for sharing. Bummer it didnt work for you. Have you tried a reducer up top like im thinking of?

Sent you a PM. Check your messages.

 

[john26]

I have not the top of my chimney is not easily accessible

 

[mellow]

I could not find the thread on the key damper in an insert, do you know where it is by chance? though not sure if I could get that to work on my setup.

Damper installation in liner?

It needs to be stainless Why is that ? Code for an insert ?

www.hearth.com

 

[gusguy]

Anything ever come of this?

 

[Amin1992]

I was going to order one and had my mind changed. Well today despite having the stove dampened as far as I could and following all advice, my stove top got to 850F and burned through 15 lbs of wood in an hour and a half...

I just ordered the reducer. Figure it's worth a shot.