preventing smoke puff when opening door to reload

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
  • Hope everyone has a wonderful and warm Thanksgiving!
  • Super Cedar firestarters 30% discount Use code Hearth2024 Click here

twd000

Feeling the Heat
Aug 28, 2015
448
Southern New Hampshire
I don't know if I'm recently more sensitive to it, but the back puff of smoke has been bothering me when I open the door to reload my BK Princess insert

I have 25' of 6" liner. I've never measured my draft with a manometer, but I think it's "adequate". I can run the stove all the way up to 50's outdoor temps and still maintain positive draft.

Clothes dryer, power-vented water heater, and propane furnace are generally not running. I only open the stove door twice a day to reload.

I try to make sure there are no visible flames in the firebox before I open it, just 3-4" bed of coals. If I put a piece of white birch paper-side down on the coal bed, it will flame up and starting spilling smoke into the room before I can finish loading all 6-8 splits.

Bypass door seems to behave as expected when I open and close it, besides an annoying squeak.

Anything else I can check?
 
The only thing I figured out was to load when the stove is hotter. Otgerwise I get smoke spillage every time in that situation with the princess when I never did with the other stove. For me it is just a minor annoyance no big deal. But I already smell like a chimney 24/7 lol.
 
The only thing I figured out was to load when the stove is hotter. Otgerwise I get smoke spillage every time in that situation with the princess when I never did with the other stove. For me it is just a minor annoyance no big deal. But I already smell like a chimney 24/7 lol.

hahaha sounds like an occupational hazard.

I've been trying to ignore it, but my son mentioned it the other day, and yeah, the room stinks for awhile after a reload.

Interesting that you reload on a hotter stove - I've been doing the opposite. Trying to let all the active flames die down before reloading. Of course the delta-temperature that drives the draft will be greater at hotter stove temps. I can try that
 
Last edited:
hahaha sounds like an occupational hazard.

I've been trying to ignore it, but my son mentioned it the other day, and yeah, the room stinks for awhile after a reload.

Interesting that you reload on a hotter stove - I've been doing to opposite. Trying to let all the active flames die down before reloading. Of course the delta-temperature that drives the draft will be greater at hotter stove temps. I can try that
I find it works better that way for me. I am not sure why it spills so much.
 
Try cracking the door open for a few seconds and then open it all the way. I do this and I can leave the door open the whole time it takes to load with no smoke spillage. My setup is not ideal either - through the wall class A with a 90 at the T and then another 90 up the chimney. 18 feet of chimney.
 
Try cracking the door open for a few seconds and then open it all the way. I do this and I can leave the door open the whole time it takes to load with no smoke spillage. My setup is not ideal either - through the wall class A with a 90 at the T and then another 90 up the chimney. 18 feet of chimney.
He and I both get spillage from the new load starting to ignite so in this situation cracking the door first won't help. But it does in other situations
 
How long since the chimney was cleaned? If this is something it hasn’t done from the start your chimney cap could be partially clogged.
 
How long since the chimney was cleaned? If this is something it hasn’t done from the start your chimney cap could be partially clogged.
Certainly possible but mine has done it from the start
 
Certainly possible but mine has done it from the start
That’s a little odd. It’s not a problem I typically see with a princess unless it’s on a Tee system.
 
Mine is on a tee but within if not above draft spec.
 
You might be getting more back puffing from the high winds too.
What we are experiencing is not back puffing. It is smoke spillage from the new load when loading
 
Mine has always done it to some extent. Mine improved big time after replacing a 90 with 2 45’s. Another thing I do is turn the t-stat so it’s closed, I find this helps by limiting the air coming into the stove and pushing smoke out before it can get up the chimney. I get my best results with a cooler coal bed like the OP, when it’s really hot the new load lights up way to fast.

The Princess has been mentioned having this quirk ever since I’ve been around, the king doesn’t seem to have an issue.
 
  • Like
Reactions: bholler
Mine has always done it to some extent. Mine improved big time after replacing a 90 with 2 45’s. Another thing I do is turn the t-stat so it’s closed, I find this helps by limiting the air coming into the stove and pushing smoke out before it can get up the chimney. I get my best results with a cooler coal bed like the OP, when it’s really hot the new load lights up way to fast.

The Princess has been mentioned having this quirk ever since I’ve been around, the king doesn’t seem to have an issue.
It's funny I get best results doing exactly the opposite. What ever works
 
  • Like
Reactions: rdust
Another thing I do is turn the t-stat so it’s closed
It's funny I get best results doing exactly the opposite. What ever works
Normally, if you let less air come in through the primary air, more will have to come in through the door which should result in less spillage.
Loading hotter like you do, draft is stronger so that is probably helping in your case. Yep, whatever works, you just have to experiment.
 
  • Like
Reactions: dBrad
Normally, if you let less air come in through the primary air, more will have to come in through the door which should result in less spillage.
Loading hotter like you do, draft is stronger so that is probably helping in your case. Yep, whatever works, you just have to experiment.
As soon as you open that door there is no air being pulled through the intake. I open it up to heat the stove up more and increase draft.
 
As soon as you open that door there is no air being pulled through the intake. I open it up to heat the stove up more and increase draft.
Probably not much, and it may vary depending on the stove. I've see posts saying closing the primary helped in some cases, though.
 
How long since the chimney was cleaned? If this is something it hasn’t done from the start your chimney cap could be partially clogged.

I cleaned with the Soot Eater before this season. It has behaved like this from the start - not sure if it is getting worse, or it's just bothering me more lately
 
Mine has always done it to some extent. Mine improved big time after replacing a 90 with 2 45’s. Another thing I do is turn the t-stat so it’s closed, I find this helps by limiting the air coming into the stove and pushing smoke out before it can get up the chimney. I get my best results with a cooler coal bed like the OP, when it’s really hot the new load lights up way to fast.

The Princess has been mentioned having this quirk ever since I’ve been around, the king doesn’t seem to have an issue.

Agreed. It’s really hard to reload this stove hot (fuel remaining) without spilling smoke. I tried cracking the door but that just gets the remaining fuel flaming up and making more smoke.

What’s odd is that starting a cold stove the flue has no problem sucking every bit of smoke. It’s just the hot reload that spills.

My best luck is to shut the stat, open the bypass for a couple of minutes to cool the cat, then open the door just far enough to reload. Then latch the door and open the stat to char the fresh wood.

The bypass opening to the flue looks to be lower than the top of the door opening. Seems like the door should be lower.
 
  • Like
Reactions: bholler
What’s odd is that starting a cold stove the flue has no problem sucking every bit of smoke. It’s just the hot reload that spills.


I noticed that too. On a cold start, I can leave the door open as wide as I want for as long as I want without smoke spilling out into the room. Once the stove is hot, opening the door any amount spills smoke, no matter how low the bed of coals is simmering
 
What we are experiencing is not back puffing. It is smoke spillage from the new load when loading
You are not the first to report this. I think that is somewhat inherent in the sloped front design.
 
  • Like
Reactions: rdust and bholler
My Drolet does not puff smoke into the room unless I whip the door open quick or a log catches fire while part of it still sticks out the door.
So it pretty much never happens.
My chimney SS Liner is about 21' tall from top of stove till chimney cap. 6" round.
 
My best luck is to shut the stat, open the bypass for a couple of minutes to cool the cat, then open the door just far enough to reload.
After bholler said "As soon as you open that door there is no air being pulled through the intake," I got to wondering if I could see how much difference it makes on my stove, air shut vs. open. This pic is shot vertically from the bottom/back of the stove, and shows how visible the air intake is. It should be easy with a stick of incense, testing both the door opening and the intake, to tell how much difference there is, air open vs. shut. But right now, my rear heat shield is blocking easy access, so I'd have to remove it before I can check.
[Hearth.com] preventing smoke puff when opening door to reload
The bypass opening to the flue looks to be lower than the top of the door opening. Seems like the door should be lower.
Might be hard to see, but the flue exit is at the right/top of this pic, to the right of the light-colored piece, slanting down toward the back of the stove. You can see a hex bolt head in the cast bypass frame/flue exit The front (highest point of the opening) is still about 1" below the top of the door opening. The rear of the slanted flue exit may be 2" below the top of the door opening.
I don't get smoke roll-out on 16' of stack, even though the stove is rear-vented. There are some areas in the top of the fire box that are higher than the door opening, like the air wash and the side area between the flue exit and the door...maybe that helps? The draft is also focused on a smaller opening with my side-loader...on a front-loader you have a much larger opening. Less draft per sq.in. of opening.
[Hearth.com] preventing smoke puff when opening door to reload