Combustor looks like it isn't working - why?

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MCC

New Member
Apr 20, 2022
25
ARGYLE, WISCONSIN
Hello,

I'm new to this Princess 32 and have been burning it for a few months now. All was going well and it was behaving the same as I have read on here in the shoulder season up until the last couple of weeks perhaps. I've been burning Red Elm and Ash, both of which test between 14 to 20 percent moisture. The last few weeks have been really cold and I was running it a lot harder than before. What I started noticing is more smoke out the chimney. Today I did not leave my house and noticed it smoking pretty much all day. I reloaded it with 4 splits(half load) and went into my shop. My wife called me 40 minutes later and says she had turned the stove down to 3:30 on the temp control and about 10 minutes later, she saw a flame rise up to the top, heard a puff, looked and saw smoke come out of the stove someplace. I immediately looked at the chimney and it was emitting smoke like it has been all day(we are above freezing). I checked the door gasket and the dollar bill test was good. I reloaded it full, ran it up to max temp for 30 minutes, the cat probe went to the max end of the white and I could see the combustor lightly glowing, backed the throttle off to 3 oclock. The cat gauge dropped within 30 minutes to just barely in the active zone, the cat is no longer glowing and there is plenty of smoke coming out the chimney.

I'm hoping I can just vacuum it off or something. I am more than frustrated as I have gone to great lengths to make sure to treat the combustor as good as I know how to to get long life. Careful to run it hot after each reload for 20 to 30 minutes and never open the door with it closed. Why would something like this happen all ready? Is this typical and I just need to vacuum it off every month or so? I will remove the flame shield tomorrow after it cools off and look at the combustor face. If it is ashed up, could it be my wood is too wet? All of my wood was cut this spring and so it could be suspect. but the pieces I've checked all tested 14 to 20 percent.

What are your thoughts and experiences?
Thanks,
Dan
 
Hello,

I'm new to this Princess 32 and have been burning it for a few months now. All was going well and it was behaving the same as I have read on here in the shoulder season up until the last couple of weeks perhaps. I've been burning Red Elm and Ash, both of which test between 14 to 20 percent moisture. The last few weeks have been really cold and I was running it a lot harder than before. What I started noticing is more smoke out the chimney. Today I did not leave my house and noticed it smoking pretty much all day. I reloaded it with 4 splits(half load) and went into my shop. My wife called me 40 minutes later and says she had turned the stove down to 3:30 on the temp control and about 10 minutes later, she saw a flame rise up to the top, heard a puff, looked and saw smoke come out of the stove someplace. I immediately looked at the chimney and it was emitting smoke like it has been all day(we are above freezing). I checked the door gasket and the dollar bill test was good. I reloaded it full, ran it up to max temp for 30 minutes, the cat probe went to the max end of the white and I could see the combustor lightly glowing, backed the throttle off to 3 oclock. The cat gauge dropped within 30 minutes to just barely in the active zone, the cat is no longer glowing and there is plenty of smoke coming out the chimney.

I'm hoping I can just vacuum it off or something. I am more than frustrated as I have gone to great lengths to make sure to treat the combustor as good as I know how to to get long life. Careful to run it hot after each reload for 20 to 30 minutes and never open the door with it closed. Why would something like this happen all ready? Is this typical and I just need to vacuum it off every month or so? I will remove the flame shield tomorrow after it cools off and look at the combustor face. If it is ashed up, could it be my wood is too wet? All of my wood was cut this spring and so it could be suspect. but the pieces I've checked all tested 14 to 20 percent.

What are your thoughts and experiences?
Thanks,
Dan
Could it be that my Cat is just coming out of the brand new hyper active stage and this is how fast it can drop when turned down to 3 with a seasoned cat? If so, Im still emitting way more smoke than a month ago and what the heck happened to my wife when she had a mini backfire and how would smoke come into the living area with the door sealed shut?
 
You will typically see some smoke from the chimney periodically when the cat is active, but it shouldn't be heavy. The cat also may not necessarily glow, even though it is active and glowing.

All of this together though, backpuffing, etc., with your statement that the wood was cut this spring, sounds symptomatic of wet wood.

How are you testing your wood moisture content? You should be testing on the inside of a freshly split piece that has spent ~24 hours indoors.
 
The back puff is from turning the air down too far too quick for your current weather conditions. To keep your Cat up higher in the active range your 330 setting during bucky cold temps may end up between 330 and 4 in the current warmer above freezing weather. Warm outside temps equal less draft. Less draft equals more air required to maintain the desired burn rate. Theoretically! Play with it. Its rather unlikely your new stove has failed in any meaningful way. My opinion.

Your fresh Cat will definitely be less reactive after several burns. Completely normal.

Grab a random handful of your splits and put them indoors overnight to get them up to room temp. Take each split back outside and re-split them. Immediately check the freshly exposed inner surface for an accurate m/c reading. Post what you find. Enjoy the learning curve. Good luck.
 
Ok, I pulled the flame shield off last night and from what I could tell the combustor looked fine. I took moisture readings tonight on several splits. All of the Ash tested between 15% to 17%. All of the Red Elm tested between 17% to 19%.

I swear the stove is behaving differently than it did at first in two ways. First, I am seeing smoke often out the chimney, but it varies in thickness and it smells good sometimes and stinks other times. Is this normal?

The other thing is I think the combustor gauge drops off much faster than it ever did before. Last night I loaded the stove full with Ash splits. I ran it on high for 30 minutes and the combustor read about 3 oclock or at the max end of the white portion. I turned the stove air to about the 4 oclock postion and within a half hour, the combustor gauge was reading at about 10 oclock position for an hour and then I fell asleep. I woke up about 2 hours later and the combustor gauge was reading about 4 oclock or past the white. I woke up about 5 hours later and the combustor gauge was at about 9 oclock. Does this seem normal? It used to be that the combustor temp would stay up at the 2 oclock position until most of my wood was gone several hours later. Now it seems the combustor drops off very fast after the initial 30 minute high throttle setting while charring a fresh load.

I have attached a couple of pics. I think it looks fine from what you can tell from just looking at the face. Also, is the amount of creosote on the walls normal?

Maybe all of this is normal as the CAT gets broken in, it just seems different than before.

Thanks,
Dan

stove 3.jpg stove 2.jpg stove 1.jpg
 
I can’t tell from your post how old this stove is. Or more specifically how long you’ve been burning on this catalyst. They don’t last forever. The PE 32 model is pretty new but that’s a steel cat and I didn’t even get two years from steel.
 
I took moisture readings tonight on several splits.
Not to nitpik. Just verifying.
Did you test those splits as described? Room temp? Re-split room temp split just prior to testing on the freshly exposed inner surface? Gotta ask as it's a real issue. So, so many new members answer adamantly that they have checked M/C over and over.
Only to finally admit they are checking the outside or ends of the splits. Zero accuracy.

Your Cat reaction sounds a bit odd. When you close your bypass are you rotating past the initial tight spot to the final "clunk" locked position? Just a stab in the dark question?
 
I can’t tell from your post how old this stove is. Or more specifically how long you’ve been burning on this catalyst. They don’t last forever. The PE 32 model is pretty new but that’s a steel cat and I didn’t even get two years from steel.
So when the time comes , you would recommend a ceramic cat?
 
Not to nitpik. Just verifying.
Did you test those splits as described? Room temp? Re-split room temp split just prior to testing on the freshly exposed inner surface? Gotta ask as it's a real issue. So, so many new members answer adamantly that they have checked M/C over and over.
Only to finally admit they are checking the outside or ends of the splits. Zero accuracy.

Your Cat reaction sounds a bit odd. When you close your bypass are you rotating past the initial tight spot to the final "clunk" locked position? Just a stab in the dark question?
I took the splits out of my 50 degree storage area and split them outside and immediately tested them. I checked a couple of spots in the middle on each fresh surface from the splits.

I am closing the bypass all of the way.

The stove seems to be acting more like it used to. Even though my cat didn't look that bad to me, perhaps it was slightly obstructed with ash and vacuuming it restored some efficiency. IDK, but am happy with how it burned the last two loads. I got 14 hours out of the last load of ash running with the throttle at the 4 oclock position and the cat thermometer hovering around the 11 to 12 position for most of the load. I could have gone longer but will be going to bed soon. At this point, I'm not worried about it and if it starts acting funny again, I'd start by vacuuming the combustor.
 
So when the time comes , you would recommend a ceramic cat?
Yes. Cheaper, longer lasting, bigger holes less likely to clog, yeah I definitely prefer ceramic. The good news is that you can try one of each and decide for yourself.

Both will work well at first and a new cat always works great compared to the old expired cat.