Smoke with cat engaged - Chinook

[Highbeam]

Thanks for the input! I'll have to try a quick turn to re-seat the flapper when this happens and see if that corrects the issue. I was just wondering in an above post if something was getting hung up in the mechanism, perhaps due to slower incremental turning of the thermostat knob. That's an interesting thought about the tension in the coil. I suppose it is plausible that there could be an improperly wound coil or just a manufacturing defect, as my stove is pretty new.

Where the throttle shaft slides through the casting is where it can stick and bind. On a carburetor there are fancy bushings here to support that shaft and a strong vacuum below plus a strong throttle return spring. The BK stat is just a steel shaft in an alloy hole. If you remove the stat cover to inspect this you can easily feel how little spring tension is provided by the bimettalic coil when it is at rest or in a static position. Like open the throttle blade a bit with the knob and then with your finger lightly tap the throttle blade and it doesn't bounce back to to the same place every time. That low strength can be why your throttle blade isn't quite doing the job if there is even the slightest bit of fouling in that throttle shaft bushing area.

CLean clean clean. Then lubricate with something like silicone lube that dries completely because if it's sticky it can accumulate dust and bind again.

 

[TheElementalCashew]

Chiming-in!! The thermostat is an east part to replace. I don't think there is an issue with yours, but not being able to "touch" it makes that determination very difficult. You can call and ask the dealer initiate a warranty claim, but that moves this from this wonderful hearth site to the process we use. Always free to report back of course!!

Thanks! Any issues with popping off the cover for the thermostat to just take a look?

 

[Ashful]

Thanks! Any issues with popping off the cover for the thermostat to just take a look?

Not BKVP, but I can answer in this particular case: no, we've all done it!

 

[BKVP]

Not BKVP, but I can answer in this particular case: no, we've all done it!

Make 100% it is horizontal when you reinstall cover

 

[TheElementalCashew]

Where the throttle shaft slides through the casting is where it can stick and bind. On a carburetor there are fancy bushings here to support that shaft and a strong vacuum below plus a strong throttle return spring. The BK stat is just a steel shaft in an alloy hole. If you remove the stat cover to inspect this you can easily feel how little spring tension is provided by the bimettalic coil when it is at rest or in a static position. Like open the throttle blade a bit with the knob and then with your finger lightly tap the throttle blade and it doesn't bounce back to to the same place every time. That low strength can be why your throttle blade isn't quite doing the job if there is even the slightest bit of fouling in that throttle shaft bushing area.

CLean clean clean. Then lubricate with something like silicone lube that dries completely because if it's sticky it can accumulate dust and bind again.

Thanks! I'll pull the cover this weekend and check things out, cleaning where necessary and I'll have to get some high-temp dry lubricant for it.

 

[TheElementalCashew]

Make 100% it is horizontal when you reinstall cover

Roger that.

 

[Highbeam]

Thanks! I'll pull the cover this weekend and check things out, cleaning where necessary and I'll have to get some high-temp dry lubricant for it.

Drop a bit of lube onto the spring washer too. Right where the rod hits the alloy stat body. I might do the same here soon.

Oh and a #2 square drive.n Just the two black ones down low.

 

[Poindexter]

TL, DR. I got through page one. The main thing to suss out is the difference between actual smoke(pollution) and steam (water vapor).

Diabel's pics in post #22 this thread show an attached plume, so we cannot suss out steam from smoke in the pictures.

The curriculum for EPA level 9 VEE (visual emissions evaluation) is free online. You got to pay the $ to take the test and become certified for 9VEE, and there is a separate curriculum (and test and fee) for nighttime 9VEE.

If you are seeing steam coming out of your stack, your stove is running fine and your environmental impact is low to very low. If you are seeing actual smoke, your stove needs maintenance.

I am not a certified 9VEE, but I have a good grasp of the curriculum. Running fuel at 13-15% MC in a well maintained stove purchased new in 2014, my plume typically runs 0-5% opacity, with 0% far and away the most common finding. My local AQ police are looking for opacity in excess of 20% .

FWIW the curriculum for 9VEE explicitly forbids rating plume opacity from pictures or video, in person direct observation is required by regulation.

If there are pics of the OPs plume on pages other than page one please let me know where to look. Thanks.

 

[BKVP]

You can order a Ringelmann chart online.

 

[TheElementalCashew]

Where the throttle shaft slides through the casting is where it can stick and bind. On a carburetor there are fancy bushings here to support that shaft and a strong vacuum below plus a strong throttle return spring. The BK stat is just a steel shaft in an alloy hole. If you remove the stat cover to inspect this you can easily feel how little spring tension is provided by the bimettalic coil when it is at rest or in a static position. Like open the throttle blade a bit with the knob and then with your finger lightly tap the throttle blade and it doesn't bounce back to to the same place every time. That low strength can be why your throttle blade isn't quite doing the job if there is even the slightest bit of fouling in that throttle shaft bushing area.

CLean clean clean. Then lubricate with something like silicone lube that dries completely because if it's sticky it can accumulate dust and bind again.

I pulled the cover for the thermostat this weekend on a warmer day. It was pretty dirty under there (dogs), but everything seemed to be moving smoothly. I cleaned everything up and put some dry lube on the moving parts. I also confirmed that the flapper closes right about 2 on my dial.

No changes in operation though. Last night I reloaded around 530pm on hot coals and an active cat, and had it cruising by 6pm. When we headed to bed around 730pm the stove was running perfectly, thermostat at about 2, draft about 0.05WC, dark firebox, and cat temp indicator over towards the 2-3 position.

Rolled downstairs at about 430am this morning to a pretty warm house and an empty firebox. There were a few coals lingering, and the cat was just into the inactive zone, and I had to use a firestarter to get things going again.

TLDR; cleaned the thermostat, still only got ~11 hour burn time on a full firebox.

Is it possible/safe to run the stove with the cover for the thermostat off, to see if it's doing anything weird during the burn? My gut tells me no...

 

[BKVP]

I pulled the cover for the thermostat this weekend on a warmer day. It was pretty dirty under there (dogs), but everything seemed to be moving smoothly. I cleaned everything up and put some dry lube on the moving parts. I also confirmed that the flapper closes right about 2 on my dial.

No changes in operation though. Last night I reloaded around 530pm on hot coals and an active cat, and had it cruising by 6pm. When we headed to bed around 730pm the stove was running perfectly, thermostat at about 2, draft about 0.05WC, dark firebox, and cat temp indicator over towards the 2-3 position.

Rolled downstairs at about 430am this morning to a pretty warm house and an empty firebox. There were a few coals lingering, and the cat was just into the inactive zone, and I had to use a firestarter to get things going again.

TLDR; cleaned the thermostat, still only got ~11 hour burn time on a full firebox.

Is it possible/safe to run the stove with the cover for the thermostat off, to see if it's doing anything weird during the burn? My gut tells me no...

View attachment 304610 View attachment 304611 View attachment 304612

YEs, as long as you are there for the duration of the burn. Can you post picture of your "full load" please?

 

[TheElementalCashew]

YEs, as long as you are there for the duration of the burn. Can you post picture of your "full load" please?

Not the load in question, but this is pretty standard for me, except I typically pack in some smaller stuff into the gaps.

 

[Highbeam]

Not the load in question, but this is pretty standard for me, except I typically pack in some smaller stuff into the gaps.

View attachment 304613

That’s a 24 hour load for me when using Doug fir and running on low with 400 degree flue temps.

 

[BKVP]

Not the load in question, but this is pretty standard for me, except I typically pack in some smaller stuff into the gaps.

View attachment 304613

Thank you. On your next "low" burn, post picture of thermostat blade/assembly setting. Looks like 7 pieces (?) for this load. Do you have larger diameter pieces? If so, try some big pieces (say 4-5) that would mostly fill and then add smaller pieces.

 

[TheElementalCashew]

Thank you. On your next "low" burn, post picture of thermostat blade/assembly setting. Looks like 7 pieces (?) for this load. Do you have larger diameter pieces? If so, try some big pieces (say 4-5) that would mostly fill and then add smaller pieces.

I'll see if I can dig out some larger pieces to use all at once.

 

[Nealm66]

Even a cotton wood load like that will give me 12 hours easily.

 

[QuarryHouse]

Even then, it likely due to a loose set screw in the thermostat knob. Easy fix.

Work got very busy, thus the delay. The thermostat knob turns and turns - there is no stop - but if I push it in while turning, it does open and close the damper. It takes almost a full revolution for it to go from closed to WOT, which is not what happened fresh off the truck. It functions, but seems like something's loose. Is there a repair procedure? The manual says thermostat adjustments should be done by someone who knows what they are doing, which considering I didn't lock the cat down at first, definitely isn't this guy.

 

[BKVP]

Work got very busy, thus the delay. The thermostat knob turns and turns - there is no stop - but if I push it in while turning, it does open and close the damper. It takes almost a full revolution for it to go from closed to WOT, which is not what happened fresh off the truck. It functions, but seems like something's loose. Is there a repair procedure? The manual says thermostat adjustments should be done by someone who knows what they are doing, which considering I didn't lock the cat down at first, definitely isn't this guy.

Contact the dealer for a replacement thermostat. They cannot be calibrated in the field.

BKVP

 

[QuarryHouse]

Contact the dealer for a replacement thermostat. They cannot be calibrated in the field.

BKVP

Thanks. Will do.

 

[TheElementalCashew]

I’m beginning to think I have a bad thermostat. I took the cover off my thermostat and monitored the flap through the day. For a few hours after achieving cruise, the flap stayed just a bit open while the knob was set to about 2. However, as the burn continued the flap actually opened a bit more and stayed there. I rotated the knob to about 1, which basically returned the knob to slightly open. The burn continued to get hotter, so I backed the knob back all the way to 11, which closed the flap entirely. Keep in the mind at cold stove and during the beginning of the burn/cruise, closed flap was right about 1-2.
I let the fire cool a bit and the cat temp to drop close to inactive, over about 30-45 minutes. Then I started to rotate the knob back from 11 towards 2. The flap stayed closed until I reached about 2, so it seemed the thermostat had returned to how it should be/used to be.
I took a bunch of pictures, but they don’t really make sense without some sort of order.

If I was to stand and watch the flap over about 30 minutes while the fire is cruising, could I expect to see the flap making small adjustments? I did this, but didn’t see any movement at all except for those made if I turned the knob. The flap did adjust more open by itself when it started getting hotter, but I wasn’t watching it actively at the time.

Worth noting the I am keeping the draft in spec with a manometer and key damper.

All this seems to be counter the intent of burning with a thermostat, and I’d certainly not expect it to introduce more air when the fire is already quite hot. While not the end of the world, I expected this to be more or less set it and forget it once the fire is cruising, not returning to back off the air hours later so it doesn’t burn out. @BKVP is it possible that I have a bad thermostat, or is this expected performance?

 

[Ashful]

The flap did adjust more open by itself when it started getting hotter, but I wasn’t watching it actively at the time.

Worth noting the I am keeping the draft in spec with a manometer and key damper.

All this seems to be counter the intent of burning with a thermostat..

Agreed, this is the opposite of what you would expect it to do. Likely best to do a burn when you're home, so you can get better data / photos, since you say you weren't really watching it closely at that point. If you can confirm that's indeed what is happening, you almost have to wonder if the coil was installed backwards?

Maybe @BKVP forgot to send the Christmas bonuses, and pissed off the QA people in final inspection. Jelly of the Month Club memberships don't cut it!

 

[stoveliker]

I concur with ashful, but do have one question: you said

"Worth noting the I am keeping the draft in spec with a manometer and key damper."

Did you adjust the damper during the described run? Or did you have it set at one setting throughout the burn?

That might be relevant as it adds a varying variable.

 

[TheElementalCashew]

Agreed, this is the opposite of what you would expect it to do. Likely best to do a burn when you're home, so you can get better data / photos, since you say you weren't really watching it closely at that point. If you can confirm that's indeed what is happening, you almost have to wonder if the coil was installed backwards?

Maybe @BKVP forgot to send the Christmas bonuses, and pissed off the QA people in final inspection. Jelly of the Month Club memberships don't cut it!

It can’t be installed backwards, I’d think this behavior would be visible earlier in the burn and more consistently if that was the case. But something is certainly weird about it, maybe an improper calibration?
It’s tough to dedicate that many hours to just watching the back of the stove. Perhaps I should set a camera to record it or something.
I did take some pics.

Hopefully these show in order of how I had to turn the dial, all in the space of ~2 hours today.

 

[TheElementalCashew]

I concur with ashful, but do have one question: you said

"Worth noting the I am keeping the draft in spec with a manometer and key damper."

Did you adjust the damper during the described run? Or did you have it set at one setting throughout the burn?

That might be relevant as it adds a varying variable.

The damper was static, not changed at all. I typically set it following the high burn, and don’t change it until I reload.

 

[TheElementalCashew]

I reloaded an hour or so ago. After a high burn, I had turned the dial back to 2, where the flapper was just a bit open. I checked back on the fire and it was running lower than I’d like, so I moved the dial up to about 3. Rather than the flapper open, it dropped shut….what? 🤔
I rotated back to around 2 and then back to the 3, and then the flapper closed and opened as expected.