Princess PE-32, my second year. Stove pipe, blower, stack height, shields, and damper type questions.

[moresnow]

Inspect your cap. It may have a spark arresting screen that is plugging. Very, very common issue with your exact results. Sometimes difficult if not impossible to see from the ground.
May as well sweep the pipe entirely. Clogging/restriction can occur much quicker than one would expect.
Pull the connector pipe off the stove and clean out the stove around the bypass assembly and behind the catalyst.
likely you just need normal maintenance. Good luck.

 

[stoveliker]

I agree with the cap .

A leaking flue may exacerbate buildup because air being sucked in will cool flue gases.

 

[RDPRDP]

Update: I arrived at the building yesterday, and I've attached a picture and video of the ouside when I'm reloading, and the cat is not engaged. While the comments might be 100% accurate (spark arrestor), this video to a person like me suggests there is little to no blockage. I also took a picture of the stove pipe from the bypass last night, and it was clean as a whistle. Now, in regards to the cap, I don't have a factory spark arrestor, but I have a bird arrestor home made cage, that probably has the same impact. The installer arrives tomorrow, let's see what he says. I like the comment about the leaking flue potentially sucking in cool air.

For anyone who says I should get rid of the cap, how am I supposed to deal with snow coming down into it when I am not around (only visit once per week). I get a lot of snow over the season, and the cap either will be on, or off permanently as I have no reasonable access to it at anytime of the year.

thanks,
RDP

 

[Highbeam]

Oh yeah, my money is in that silly screen being clogged. Can’t you just remove the screen and put the cap back on?

 

[RDPRDP]

Oh yeah, my money is in that silly screen being clogged. Can’t you just remove the screen and put the cap back on?

I can, but will require scaffolding to get up there to do it, and that is without snow to deal with in the spring. If I try to do it now I have tons of snow to move to put in the scaffolding. 20 feet deep under the roof at the moment! Very hard roof to deal with!

If I could push out the screen and the current cap from the stove that would do it, but then I would be capless untill the spring. I also could damage the roof when the cap and screen fall down after being pushed out.

I need a helicopter.......

RDP

 

[BKVP]

I can, but will require scaffolding to get up there to do it, and that is without snow to deal with in the spring. If I try to do it now I have tons of snow to move to put in the scaffolding. 20 feet deep under the roof at the moment! Very hard roof to deal with!

If I could push out the screen and the current cap from the stove that would do it, but then I would be capless untill the spring. I also could damage the roof when the cap and screen fall down after being pushed out.

I need a helicopter.......

RDP

Just find a kid with a drone. Fly up, get a good look and get some "possible" contributing evidence.

BKVP

 

[kborndale]

Binoculars work well for chimney screen inspection.

 

[RDPRDP]

Final report: Stovepipe was clean, except at the very top where the homemade spark arrestor/bird screen was. Once the build-up was removed all issues with smoke coming into the room during reloading were resolved, and the box comes up to temp easier on initial start-up as well.

Interestingly, even with my pipe freshly cleaned I never hear any sucking/wooshing sound at the air intake on the back of the stove as others have reported. I guess my next project to add some height to the stack might provide the extra draft needed to hear that sound.

Q: My chimney cap is about 40 years old, my installer says there isn't really any improvements in tech over the years to have me go as far as considering putting in a new one. Would you all agree?

thanks,
RDP

 

[kborndale]

Tech hasn't really changed, but the size of the mesh on the screen varies, get a cap with a 3/4" mesh, the finer ones plug up easier.

 

[RDPRDP]

Tech hasn't really changed, but the size of the mesh on the screen varies, get a cap with a 3/4" mesh, the finer ones plug up easier.

Just to confirm, due to creosote build-up issues on my current handmade spark arrestor/bird screen that it will be removed completely, leaving me just with the chimney cap, which I understand normally doesn't come with any screen at all. If I'm wrong about chimney caps and screens please let me know!

thanks,
RDP

 

[Tron]

My chimney has just the cap, nothing else.
Distance between the end of the flue and the cap is maybe 2-3" or so.

 

[kborndale]

No screen is fine as long as your not worried about wildlife getting in. The main thing is your wood though, dry wood produces less creosote. My cap has about a 3/4 inch screen. I sweep once a year and never have come anywhere close to it plugging up. You need to burn dry wood and burn hot on startup/reload.

 

[Highbeam]

Just to confirm, due to creosote build-up issues on my current handmade spark arrestor/bird screen that it will be removed completely, leaving me just with the chimney cap, which I understand normally doesn't come with any screen at all. If I'm wrong about chimney caps and screens please let me know!

thanks,
RDP

My chimney cap came from Simpson (duravent) with no screen. I installed it and passed inspection. On a different chimney I bought a cap with the optional removable screen and it plugged up quickly with brown crunchy stuff despite using a very low emissions stove and very dry wood.

In my area the bird problem is nearly non existent but the clogging with creosote is a very real problem.

 

[RDPRDP]

2025/2026 season update: Extended my outside stack by 1.6ft, and removed the hand-built bird cage near the cap., This was a good thing to do as my setup is now more stable, I get less smoke coming into the room on reloads, and obtain more draft (I'm hovering around the recommended total stack height, and have no bends along the way). This also brings me closer to being compliant with the 3-2-10 rule. It wasn't cheap to do all this, but as it's a noticeable improvement I'm happy with the results.

As I cannot keep from fiddling with this thing my project this year was to try and get longer burns without stalling during the shoulder season. I cannot do this in the winter as my log building is drafty and I need all the heat I can get (I reload every 12 hours during peak cold days, dial set to around 4:30pm). I've been monitoring other threads here about people with long burns, and there is no way I can go above 15 hours without stalling the cat. Therefore I decided to take a look at what my flap was doing (yes, I read all the BKVP warnings):

Cold stove:
Flap FULLY closed (touching the frame, only air going through the emergency round hole): 2pm on the dial.
Flap FULLY open (about a 45 degree angle, photo "179" shows this): 5pm on the dial. Turning past 5pm the flap does not open any further.

Hot stove:
Flap FULLY closed (touching the frame, only air going through the emergency round hole): 330pm on the dial.
Fap FULLY open (about a 45 degree angle, photo "179" shows this): 6pm on the dial (however, it might go higher if could move the dial past 6pm to about 630, but this is close enough, and I don't plan on messing with the set screw).

So, in my situation, when the stove is hot/operating, if I go below 3:30 on the dial, in a few hours the cat will stall. Therefore I can only get around 15 hours out of it with the dial just open to about 3:45/4pm (flap open just a hair).

Does this sound right?

There seems to be some damage to both sides of the frame the removable flap cover sits on, can I assume this has NO BEARING on safety or performance? I've added some photos to better describe this. The "flap box" welds also seems to be having some gaps where they connect to the main body of the stove. Also no problem/concern at all?


thanks all,
RDP

 

[Tron]

if I go below 3:30 on the dial, in a few hours the cat will stall.

I wouldn't say that. If it's hot and you're dialing down, the flap will close, yes, but that doesn't mean it's going to stay this way. Once the stove has cooled to adjust to your lower heat demand, the flap will open again to keep it at temperature (without a cat stall).

I can run mine at around 2:50 without the cat stalling, but that's about it. At 3:00 it certainly won't stall.

 

[stoveliker]

^^ That.
The flap moves when you don't touch it, during the burn. That's the whole point of the bimetal thermostat controlling the air. Dial down to 3.30 it may close b/c the stove is hot. But dialing up to 3.30 it will likely be open (to some degree).

Also, "less smoke in the house" to me suggests your draft is still marginal. That is consistent with it possibly stalling at a higher thermostat setting than in many other installs.

How tall is your flue now?

 

[RDPRDP]

^^ That.
The flap moves when you don't touch it, during the burn. That's the whole point of the bimetal thermostat controlling the air. Dial down to 3.30 it may close b/c the stove is hot. But dialing up to 3.30 it will likely be open (to some degree).

Also, "less smoke in the house" to me suggests your draft is still marginal. That is consistent with it possibly stalling at a higher thermostat setting than in many other installs.

How tall is your flue now?

I'm just around manual spec for my elevation right now. 16.5ft is my best guesstimate for total height (no bends) and elevation is just around 3,100ft/950m. I'm also running double wall insulated pipe, and I don't think the manual specs takes that into account (just the elevation and number of bends). I'm in decent shape, and pleased with the current conditions, certainly better than before!

To clarify, I'm only getting a small amount of smoke roll-out from the top lip of the door if the stove has really cooled off and I can't get much more heat into it while prepping for the next load to go in, so I see this as happening only very rarely, and the lesson for me is just to ensure that I've got a bit of draft going and SLOWLY open the door for the reload. If enough coals then the issue is basically non-existent. Of course if things are blustery out, then all bets are off!

RDP

 

[RDPRDP]

I wouldn't say that. If it's hot and you're dialing down, the flap will close, yes, but that doesn't mean it's going to stay this way. Once the stove has cooled to adjust to your lower heat demand, the flap will open again to keep it at temperature (without a cat stall).

I can run mine at around 2:50 without the cat stalling, but that's about it. At 3:00 it certainly won't stall.

I'm not at the house all the time, and my opportunities to observe the stove critically are few and far between, hence my delay in replying. After reading your comments, that tracks with what I'd expect. However, it's not really how my stove works. I'm not sure if the thermo is wound backwards (I've read about that for a few people), or what the issue is, but I even went as far as taking two time-lapse videos to make sure I wasn't just imagining things.

Latest observations:

When the stove is cold the flap is able to open to it's highest position (45 degree angle) when the dial is wide open , and the flap closed is when the dial is around 2pm.

When the stove is hot, the flaps highest position is now restricted down to around 5pm on the dial, and moving the dial between 5pm and 6pm (wide open) does nothing. At this time the flap closed position is now around 330pm. Effectively the cold range of 2pm to 6pm on the dial has compressed to 330pm to 5pm of available manual adjustment control.

The two observations above I understand to be normal operating spec.

Where things go off for me (maybe this is also on spec, but comments welcome):

Chance observation: When I built my last fire and eventually brought the catalyst probe to about 2pm on it's dial I started to shut the stove down, and as per the manual didn't do this in one move, but split the turn on the dial into two separate movements separated by a number of minutes. When I did this, the flap obviously moved toward the closed position due to me actuating the dial, but once I released the dial the coil also started to do it's thing, but instead of further CLOSING the flap, it actually OPENED the flap. I found this a but confusing, but maybe I don't understand some of the physics at play.....

Closing down the stove: Unfortunately, my two time-lapse videos substantiated my previous observations, and that is if I close the stove down to attempt a long burn (this is literally just love-tapping the flap to the housing, then giving it 1mm of space to ensure it can breathe) the flap will not open or adjust AT ALL even over the course of a number of hours, and this is where I will eventually stall. The only time the flap will open back up again is when the stove starts to really cool down (e.g. it's going into a full shutdown, I won't be re-loading), then it will start to raise on it's own but it takes ages to do this. In order for my stove not to stall that opening of the flap needs to happen hours earlier.

This also means that for every burn I do, once I get to around the final quarter of the burn I need to be manually adjusting the dial up every hour or so to ensure the load is fully consumed (ash, not charcoal), and the catalyst doesn't stall.

So, I'm a bit stumped......

thanks,
RDP

 

[stoveliker]

The manual recommends a double wall stove pipe and insulated chimney, so that is the premise for its height recommendation.

Your chance observation seems fine. You just dialed it down to a lower setting than its actual temperature at the time, leading to the dial opening. It'll close later when it has warmed up more

Regarding the second observation, this is a bit puzzling, but the thermostat does not control based on the cat temp. I.e. a cat stall may not directly correlate to the heat generated at the lowest setting. But it is a bit odd imo indeed.

Note that you don't need to back off a mm for it to breath; that's what the hole is for in the flapper.
If it doesn't breath enough using only the hole, I still think your draft is a bit below the minimum. (Flue height could use a foot or two more.)

 

[Highbeam]

Sure sounds like wet wood or poor loading just not wanting to keep burning. I'm also a little curious about how with a cold stove and fully hot dial setting the flapper is not fully opened. Is that normal for other owners? On my princess she goes way open, that flapper runs up to a hard stop against the screw in the cover.

 

[Tron]

Regarding the second observation, this is a bit puzzling, but the thermostat does not control based on the cat temp. I.e. a cat stall may not directly correlate to the heat generated at the lowest setting. But it is a bit odd imo indeed.

Not really, I think. I also have to open up the thermostat a little towards the end of the burn to keep it from stalling. I really can't measure the heat output reliably, but I think you're right: the thermostat controls the heat output, so far, so good. But near the end of the burn what's left is mostly charcoal and no more volatile gases in the wood, so at the same heat output the cat gets less food, requiring the thermostat to be open a bit more to not stall. That would make sense to me.

Of course the whole thermostat control only works if the draft is high enough that opening the air inlet actually results in a higher stove temperature.

 

[stoveliker]

Except that CO + O2 -> CO2 happens then in the cat, and glowing charcoal is a big CO producer. (I know, for you I'd have to write 2CO + O2 -> 2CO2...)

This all depends on the relative quantities of gases produced (and relative exothermicity (?) of the associated oxidation reactions) - and we don't have enough data of the former to draw firm conclusions, I think.

 

[Tron]

(I know, for you I'd have to write 2CO + O2 -> 2CO2...)

CO + 1/2 O2 -> CO2 is also a valid way ;-)
But yes, not as common.
Stoichiometry rulez!

I'm certainly aware that glowing charcoal produces CO, but apparently with the stove dialed down it's not enough to keep the cat active. At higher outputs it's enough.
Mind, I'm totally not complaining, that only happens in the last hour or two of the burn. When I see the cat temperature slowly decrease toward the inactive range, I just turn the thermostat wide open, that works well for keeping the cat active, providing quite a bit of heat and burning down the coals.

 

[stoveliker]

Yeah, I don't bother much with that (unless it's very cold and windy outside) because of the heat reservoir that is my basement, and the bit of high burn when I reload. (And the flue doesn't get dirty from a cat getting to the inactive zone with only coals left.)

 

[Tron]

And the flue doesn't get dirty from a cat getting to the inactive zone with only coals left

No, totally agree on that. CO doesn't condense and the water (and the hydrocarbons) are all gone at that point.