Progress Hybrid house smoke and OAK

[barnaclebob]

Here is my relavent PH experience. I will get smoke spillage when i forget to open the bypass when lighting, no duh. I light my stove with a propane torch so that means sitting there for 30 seconds or a minute blasting the kindling. I'll get smoke coming out of the air intake when lighting if I leave it open during a light. As soon as I close the door to the stove it stops because the stove is now only pulling air through the intake vs the door. The smoke that comes out of the intake is only a small fraction of the total smoke generated during a light.

I will get occasional backpuffs and I don't believe its due to poor draf and I don't really consider it a major design flaw. My chimney is about 25ft in a straight shot. I have never had a poor draft in warm weather, wind storms from all directions etc. The backpuffs are due to the stove sometimes slowly building up heat until being right on the ragged edge of CAT only burn and secondary burn. When the gasses get hot enough to self ignite you get the backpuff.

If you are having smoke come out of any gaskets during an established burn, this is 100% some kind of draft issue. I understand its frustrating to be told that over and over again even though everything in your setup looks good. If your draft is good, smoke cannot exit the stove or chimney because the whole system is at a negative pressure relative to the house. Stoves combustion does not create pressure when in steady state operation. There must be some weird combination of chimney and the aerodynamics of your house. I have opened the top plate to the stove while the fire was burning down, the stove top was coming down past 300 or so and nearly all of the smoke was still sucked up the chimney, it was actually pretty cool to watch.

The most confusing part and telling part is this statement "So the >50% air setting is when there is 5-10lbs of wood, a normal load that keeps it running pretty clean. If there's more than 25lbs of wood in there it needs to be at 25% or less or it will get very hot. " I'm not sure what to make of that.

My stove does not like to run under about 400 stove top temp. If i want to run it that cool i'll have to build a small fire and keep the air open because that small of a fire wont be able to keep the cat activated if the air is shut down. With a normal load I have to keep the air all the way shut down and the stove cruises wherever it cruises. This seems typical to the stove with the 1st gen air control, i dont know how the new air control performs but i cant wait to get ahold of it.

The only thing i can think to do is start keeping a detailed log of as many burns as you can and collect as much data as you can. Wood load size, outside temps, wind direction/speed, stove top temp at various points of the burn, air setting, go outside and check the chimeny to make sure the smoke is clean etc.

 

[ValleyCottageSplitter]

Long time PH burner here. Here arethoughts.

Issue 1 is definitely a draft issue during relights. This will happen to me but only if I’m staring a new fire or very cold fire. Easy fix though I admit there are dangers involved if one were to get distracted but the fix for me is to leave the store door cracked until the flue warms. For me this is like one minute or less. I believe in my case, my oversize chimney is the cause. For you, it’s likely your exterior chimney.

Issue 2 does not appear to be a draft issue to me. I’m a little at a lose, but the smell you described reminds me of a stalled cat. Does his only happen when the cat is engaged? You mention STT but what is the fire state? If you ran it up to 400 without engaging the cat, would you he the smell.
I only run by stove pipe temps but I have single wall. Has the issue gotten worse? Does the cat clog often? The 50% open draft that you mentioned also makes me wonder about the cat.

Hey Waulie,

Thanks for your notes. The problem is that Issue #1 happens increasingly with hotter reloads. With a new fire I warm up the pipe with a heat gun for 5-10minutes or a very cold relight. There's usually almost no smoke. When I try reloading with STT above 250F or DSP outer temp above 200F it's guaranteed to get a good handful of smoke into the house. It almost seems like it takes 10secs for the flow to transition from door to intake. If smoke starts during that time it swirls out of the intake. I basically have to start with small kindling every fire to avoid this.

Issue #2 is independent of cat. WS actually recommended to just not use that cat as it could be reducing draft. It should be able to stay without the cat engaged as long as the stove doesn't get to overfire temps. I often never engage the cat because the safer small fires are just starting to peak at 350F and then they need to cool down to <200F to make sure I don't get issue #1. When I engage the cat it clearly slows the flow down but there is really no change to the fumes. It seems like it's purely temperature or high draft related. Is it possible something in the DSP could be burning? These hot fires have the outer DSP at >300F so perhaps ~600F inner pipe.

Regards,
Ian

 

[ValleyCottageSplitter]

@barnaclebob Yes I think that seems to be the exact same issue with the relights. I can't tell if it's after or before the door is closed but if the flames and smoke are starting with the door open it's going to blow some smoke out the intake (but NONE out the door!). Do you have any solutions? I was hoping someone added an OAK and fixed this blowing smoke out the intake issue, but I haven't been able to find anything. That seems like a major design flaw to me. It makes it very restrictive to try reloading the stove. Not only do the flames have to be completely gone but you have to time it so that no flames start until the door has been closed for 10 seconds.

I agree with your burning, I'm talking about small fires and need to keep the air open to get enough temp out of the stove. If I get above even 375F I start to get this woody burning smell, so naturally it's mostly very small fires with the air intake open quite a bit. I'm not sure what your "normal loads" are. I assume that is more than 50% full box.

I'm not sure there is much value in collecting the logs. The pattern is very clear. Anytime STT is over 400F and even around 375F it makes smoke.

I did mention the griddle plate was badly warped and the replacement fixed a lot of the smoke? I used to smell a lot of fumes coming from the back right corner and that is gone now. You could see marks on the top gasket where the smoke was getting blasted through. That had similar symptoms, with higher draft and temps it was worse. It's possible there's another major defect buried in the stove like this.

 

[SpaceBus]

What's the hottest you've ever gotten the stove?

 

[ValleyCottageSplitter]

When we cured it we were getting it just below red line temps, ~650-675F STT a hand full of times. Not hard get up there with a full load. The first season we got at least 1/2 cord burned above 500F but once we started getting breathing problems we quickly switched to these smaller loads. After 3-4 hot burns the paint smell went away and we could smell the woody smoke smell quite clearly. About 1/2 as bad with the fixed griddle plate.

 

[barnaclebob]

@barnaclebob Yes I think that seems to be the exact same issue with the relights. I can't tell if it's after or before the door is closed but if the flames and smoke are starting with the door open it's going to blow some smoke out the intake (but NONE out the door!). Do you have any solutions? I was hoping someone added an OAK and fixed this blowing smoke out the intake issue, but I haven't been able to find anything. That seems like a major design flaw to me. It makes it very restrictive to try reloading the stove. Not only do the flames have to be completely gone but you have to time it so that no flames start until the door has been closed for 10 seconds.

I agree with your burning, I'm talking about small fires and need to keep the air open to get enough temp out of the stove. If I get above even 375F I start to get this woody burning smell, so naturally it's mostly very small fires with the air intake open quite a bit. I'm not sure what your "normal loads" are. I assume that is more than 50% full box.

I'm not sure there is much value in collecting the logs. The pattern is very clear. Anytime STT is over 400F and even around 375F it makes smoke.

I did mention the griddle plate was badly warped and the replacement fixed a lot of the smoke? I used to smell a lot of fumes coming from the back right corner and that is gone now. You could see marks on the top gasket where the smoke was getting blasted through. That had similar symptoms, with higher draft and temps it was worse. It's possible there's another major defect buried in the stove like this.

View attachment 271542

For me the smoke only comes out the intake when the door and the intake is open and before a really good draft is established. I have good draft so I can start a fire without having shoot my propane torch up the bypass, once the chimney is heated up even more theres never an issue.

Warped gasket interfaces shouldn't allow smoke to exit after a draft is established, if anything they contribute to overfiring since more air will be getting in. But when the fires die down the smoke may find other ways out. You have said your problem is only during hot fires so that doesnt fully explain why a new plate helped. When you say your problem is only during hot fires, is it for the whole fire, just when its warming up, cruisng, cooling down etc? Have you inspected your chimney recently or during these problems? Any chance of a birds nest, dead animal, clogged cap etc?

I know a lot of people have class A pipes outside of their houses but im wondering if you have a few things working against you and all together they are creating a problem. You've got a few joints in your pipe, its outside your house so might cool off towards the end of a burn or during a cool burn, you have said your house is pretty tight i think, and maybe you have some unfavorable aerodynamics. It is very possible that an OAK will help/solve your problems but I also wouldn't be surprised if they didn't. Have you tried a burn during calm conditions where you leave the window open the whole time? Can you buy the OAK adapter and temporarily rig it up to a nearby window with dryer duct and cardboard?

As for looking for defects in the stove itself. Go through the link in my signature, i've got some detailed pictures of the interior of the stove. See if anything looks different. I doubt it will but you never know.

 

[EbS-P]

I’m going to ask two question that may be useful here.

WC is measuring a pressure difference, correct?

And could one have a pressure differential with not actual flow?
Think sucking on a plugged straw. If you have tight house it seems plausible that you could have good WC numbers but be flow restricted. In that case an OAK should make improvements. It seems like an easy enough install. I think they should required wherever possible.

Ok so I (think) I know the answer to both those questions. It what I was thinking when reading. I would have no reservations on installing the OAK.
Evan

 

[bholler]

I’m going to ask two question that may be useful here.

WC is measuring a pressure difference, correct?

And could one have a pressure differential with not actual flow?
Think sucking on a plugged straw. If you have tight house it seems plausible that you could have good WC numbers but be flow restricted. In that case an OAK should make improvements. It seems like an easy enough install. I think they should required wherever possible.

Ok so I (think) I know the answer to both those questions. It what I was thinking when reading. I would have no reservations on installing the OAK.
Evan

Yes that is why I kept asking if house pressures had been checked. Or if anyone else had checked draft etc. The numbers and symptoms make nonsense at all together.

 

[SpaceBus]

I think a blower door test would clear up a lot of questions, but I don't blame the OP for not wanting to make that investment right now.

 

[bholler]

I think a blower door test would clear up a lot of questions, but I don't blame the OP for not wanting to make that investment right now.

Not a blower door test just pressure tests in the house as it is

 

[SpaceBus]

Not a blower door test just pressure tests in the house as it is

It would determine how much make up air can get into the house, as it is a test of air tightness. If the house can't allow X CFM into the house then the stove will not work properly.

 

[bholler]

It would determine how much make up air can get into the house, as it is a test of air tightness. If the house can't allow X CFM into the house then the stove will not work properly.

Yes but it won't tell you about the pressures in the house nessecarily

 

[Highbeam]

It would determine how much make up air can get into the house, as it is a test of air tightness. If the house can't allow X CFM into the house then the stove will not work properly.

Blower door test just quantifies air leakage under a manufactured pressure. He’s already opened a door for testing that air tightness of the home is not the issue.

I’m not sure that static pressure in the home is that relevant either since the draft measurement taken already compares flue vacuum to room pressure. It’s really already a differential gauge.

 

[bholler]

Blower door test just quantifies air leakage under a manufactured pressure. He’s already opened a door for testing that air tightness of the home is not the issue.

I’m not sure that static pressure in the home is that relevant either since the draft measurement taken already compares flue vacuum to room pressure. It’s really already a differential gauge.

We don't know if the draft measurement is correct or not though. There is something not adding up the symptoms point to low draft. The draft measurement is extremely high for the height of the chimney.

 

[Highbeam]

We don't know if the draft measurement is correct or not though. There is something not adding up the symptoms point to low draft. The draft measurement is extremely high for the height of the chimney.

Right, it’s like when somebody claims their wood is measured at 7% moisture but has burning problems and bubbling water.

 

[ValleyCottageSplitter]

Thanks @fire_man. I found someone with similar problems, same year PH. He has a 30ft internal straight chimney and also working with Woodstock on this defect. So I'm going to follow his "progess" (yes, double entendre). Based on his discussions as well the OAK does not make any sense. You can have a window fully open right next to the stove and have no change with smoke coming out of the stove. It's not a house pressure or chimney issue.

Anyway, I might have contained the reloading issue based on some old posts on hearth.com. If I turn down the air almost closed right after I crack the door and then slowly open it back up after I shut the door it seems to greatly slow down smoke from getting blown out of the stove. I've done 3 reloads like this above 300⁰F and the smoke is reduced 75% to 90%. It was even 40⁰F out today. I don't know if it's delaying the ignition or changing internal pressures, but it's clearly helping. It's a huge convenience to be able to reload above 300⁰F. I can finally use up some huge 3yr red maple logs.

I have great draft in these scenarios, the sparks, smoke and flames are all very strongly vacuumed to the firebox exit and nothing visibly out the loading door.

If anyone finds this post amongst the noise, I would definitely try this out!

Still some light smoke smell at the higher temps but a lot of it was the reloading. The 30ft chimney guy has no reloading smoke but much worse hot stove smoke. So hope he fixes his problem.

 

[SpaceBus]

Sounds like you are pretty unlucky to get two bum stoves.

 

[MR. GLO]

the smoke out inlet at startup is a draft problem ...zero...because cold air is coming down chimney. you need to warm it up longer. put your hand in there and you know how long each time or get a draft guage. each day is different. once you warm it up enough you wont get smoke out inlet. yep its a pain. even a torch in there for two min might be to short of a period some times.


the smoke from reload.. ive been chasing it.
so far what i read ...could be wood could be appliances sucking or your home or location of stove or house design. or could be stove air from secondaries., venting, dirty pipes .....

you can also get a guage to read the air pressure in home vs floors vs outside too. like a draft guage.

 

[ValleyCottageSplitter]

Hey Mr. Glo,

No, I get close to no startup smoke spillage. It's mainly during hot reloads and then a small amount when it's running hot (like above 400 degrees). I warm up the flue typically about 10minutes with a heat gun if the stove is too cool. I check draft with a lighter in the flue before I light the paper. I could get a little bit of spillage otherwise.

I had another great reload this morning, a little cooler below 300, but very very little smoke this time. Stove has been cruising at 425 for about 3 hrs.

Also I left the stove at 50% air and bypass open last night with a slow burn starting on a couple big logs and came back 30 minutes to find the stove at 600 degrees . I closed the bypass and closed the air almost all the way and then it had a great overnight burn . I have to get used to loading the stove hotter! I did smell a slight amount of paint smell since we've only had it that hot a few times.

 

[SpaceBus]

I think you will find better performance and less smoke running up to 600df for even just a brief time during every burn. Sounds like you've been running the stove very low for most of the time you've been burning in it. 400df on most stove tops is a smoldering fire or the end of a burn.

 

[ValleyCottageSplitter]

Yes, even with the 450 degree burns the downstairs of our 2400 sq ft house was about 78-80 degrees yesterday at upper 30's. But when the temps get into the 20's it take quite a lot to bring up the house temperature and it usually runs the house at 69-72°F. I haven't done a single "full" load of the stove this whole year due to the smoke issues. Last nights burn was 2 logs about 7-10lbs each for example.

When I was doing larger loads the first year I was getting peak temps around 525-550°F typically.

 

[MR. GLO]

Hey Mr. Glo,

No, I get close to no startup smoke spillage. It's mainly during hot reloads and then a small amount when it's running hot (like above 400 degrees). I warm up the flue typically about 10minutes with a heat gun if the stove is too cool. I check draft with a lighter in the flue before I light the paper. I could get a little bit of spillage otherwise.

I had another great reload this morning, a little cooler below 300, but very very little smoke this time. Stove has been cruising at 425 for about 3 hrs.

Also I left the stove at 50% air and bypass open last night with a slow burn starting on a couple big logs and came back 30 minutes to find the stove at 600 degrees . I closed the bypass and closed the air almost all the way and then it had a great overnight burn . I have to get used to loading the stove hotter! I did smell a slight amount of paint smell since we've only had it that hot a few times.

Thats good news. If I smell smoke I look at chimney sometimes it blows in house from the wind.. I turn inlet up and it goes away.

 

[Woody Stover]

I'm no fluid dynamics expert..actually not an expert of any kind.
I did notice in the pic of your exterior chimney that it appears the stove may not be on the ground floor. It could be above the "neutral pressure plane" of the house. If you open a window next to the stove, air may be flowing out of that window, instead of in to supply the stove. As an experiment, you could open a window on a lower level and see if that helps. When the stove is hot, draft should be enough to overcome stack effect of the house..very perplexing.
If the top of your chimney is on the leeward side of the roof ridge from the prevailing wind, that could cause down pressure at times. If that guy is bracing the chimney, it's probably more than 5' above the roof line, and maybe 3' above the ridge, so I wouldn't think downdraft on the stack would be a problem, but who knows? Pretty sure you said you had both issues in calm winds as well, so this wouldn't be the only probelm, but might contribute.

 

[ValleyCottageSplitter]

Hey Woody Stover,

The flow clearly comes in from the window at the stove level. The pic shows the basement floor as well, the stove is on the 1st floor of a 2-story. The flow will come in from the basement windows as well and goes out upstairs windows. All as expected. As I said there are no other signs that low/reversing draft is occurring in the chimney, especially with the stove hot.

 

[bholler]

Hey Woody Stover,

The flow clearly comes in from the window at the stove level. The pic shows the basement floor as well, the stove is on the 1st floor of a 2-story. The flow will come in from the basement windows as well and goes out upstairs windows. All as expected. As I said there are no other signs that low/reversing draft is occurring in the chimney, especially with the stove hot.

Have you had a professional out yet to diagnose the issue?