New BK Princess insert... Questions.

[Blue Vomit]

The new BK Princess insert arrived and was installed last week. I have a few questions for the BK owners here. First, draft is good - 25 ft ss liner, wood is good - all at or under 20%. Block off plate installed. i have the same setup that I ran my Oslo with for 2 years.

I had my several small break in fires, gradually raising my temp up. No issues, great draft, good heat, cat engaged, no worries.
So last night I decide to try out a little of this alien technology. From a cold start, I build a fire and load about half full of dry oak. Everything is good, fire takes off. Cat therm goes into active stage, I engage the cat. Cat temp is climbing stove top temp climbing so I gradually start dialing down the tstat. Wood is charred and after about 30 min I set the tstat to the very first dot ( princess has dots, not numbers) to see about this low and slow burn.

Here is where I have a question. The cat stops glowing, which I,m not worried about from reading here, and there are no visible glowing embers but the cat temp and stove top temp keep rising. After a few min I notice the wood start to glow again along with the cat. Here comes the concerning part. The cat glow becomes increasingly brighter and brighter and the cat temp gets pegged in the active zone. Stove top gets to 620. Keep in mind I have not touched the tstat since I set it at the first dot. When the cat is at its brightest, and I mean bright!, there is a lot of smoke in the firebox. I'm guessing the wood is out gassing and the cat is working its ass off trying to eat the smoke? Cat temp and stove top temp then gradually fall. They don't really level off anywhere, they just slowly fall over the next few hours.

Is this normal? I guess I was expecting something different from hearing about "set it and forget it" and "slow even heat for long periods of time". I'm concerned that I had these temp swings on a half load of dry oak. I'm a little hesitant to load this baby up. Where is it gonna go on a full load?

Any thoughts?

 

[Blue Vomit]

I just noticed something else. I can see the tstat door opening and closing through the side vents when I turn the tstat dial. The door does not move at all when I move it from high toward low until it reaches the third dot. That's one third of a complete turn of the dial without the door moving at all. Is this normal?
At the lowest setting it does stop before completely closing, which I suspect is normal.
I don't think this would have anything to do with the stove "taking off" as described above. Just curious.
Any thoughts?

 

[Highbeam]

Your wood was in its first stage of combustion, rapid off gassing. The stove can't stop this, all it can do it eat the fuel and it does. This is one reason that BK recommends large splits.

The other thing going on is that you have a fresh, sensitive cat that is just aching to eat smoke.

Did the room overheat? I've found that the hot cat situation puts the stove top thermometer (which is right on top of the cat) and the cat thermometer into high range but the whole stove isn't actually that hot and the room doesn't overheat.

Cat stoves are funny, at times the source of heat is not the fire but the small cat element which makes parts of the stove really hot but not the whole stove. For a non-cat, the whole firebox is full of superheated lava when it runs away on you.

 

[Highbeam]

I just noticed something else. I can see the tstat door opening and closing through the side vents when I turn the tstat dial. The door does not move at all when I move it from high toward low until it reaches the third dot. That's one third of a complete turn of the dial without the door moving at all. Is this normal?
At the lowest setting it does stop before completely closing, which I suspect is normal.
I don't think this would have anything to do with the stove "taking off" as described above. Just curious.
Any thoughts?

The stat has max and minimum stops. Under normal conditions, you will hit these stops in either direction before you turn the knob fully one way or the other. You should be able to hear the sound of the flapper hitting the stops.

 

[Blue Vomit]

Your wood was in its first stage of combustion, rapid off gassing. The stove can't stop this, all it can do it eat the fuel and it does. This is one reason that BK recommends large splits.

The other thing going on is that you have a fresh, sensitive cat that is just aching to eat smoke.

Did the room overheat? I've found that the hot cat situation puts the stove top thermometer (which is right on top of the cat) and the cat thermometer into high range but the whole stove isn't actually that hot and the room doesn't overheat.

Cat stoves are funny, at times the source of heat is not the fire but the small cat element which makes parts of the stove really hot but not the whole stove. For a non-cat, the whole firebox is full of superheated lava when it runs away on you.

Thanks Highbeam,
The room did not overheat and the stove itself was not overly hot. I guess my main concern was that high cat temp and the intense bright glow of that thing. I could tell it was working hard, I just want to make sure it wasn't working too hard and damaging it.

 

[Bster13]

Does BK official recommend large splits anywhere on the web? If so I'm in trouble.

 

[Bster13]

My cat was glowing last night as well, so long as u are in the active zone, all good.

 

[Blue Vomit]

My cat was glowing last night as well, so long as u are in the active zone, all good.

Oh it was in the active zone... Almost pegged. I'm worried about it going past the active zone. And remember, this is with a half load of dry oak, fat pieces.

 

[Blue Vomit]

The stat has max and minimum stops. Under normal conditions, you will hit these stops in either direction before you turn the knob fully one way or the other. You should be able to hear the sound of the flapper hitting the stops.

I don't know about hearing it but I can see it stopping at the top and bottom. The vents on the side provide a nice view.

 

[Highbeam]

Not sure what the insert's cat meter looks like but I can assure you that it is very likely that you will exceed the active range with a fresh cat. Several members have had it happen with no ill effects. Nothing you can do about it really if the stat is shut down.

I remember the youtube BK video talking about huge splits but I don't recall if it's also in the manual. The owner's manual could use some work. Lots of information tidbits scattered all around in odd places and sometimes contradictory.

 

[Blue Vomit]

How about the fan on this baby. How important is it to keep the fan sped consistent with the tstat setting as recommended in the manual?

 

[weatherguy]

BV, when we say set it and forget it it's because we know how our stoves burn and we can put the dial where we know it will burn the way we want it to, in time you will too, your cat will get broken in and after so many loads you'll know your stove a lot better. As far as the blower, I keep mine on low all the time and adjust the tstat accordingly, which again in time you'll know.

 

[Highbeam]

How about the fan on this baby. How important is it to keep the fan sped consistent with the tstat setting as recommended in the manual?

My stove has fans and the same instructions apply of match the stat setting to the fan setting. Well, I must assume that the BK guys are worried that you'll run your fan on high with your stat on low and take so much heat from the stove that you'll stall the cat. Since fans are optional on the stove I have confidence that it is impossible to run the fans too slowly for any stat setting. So all you're worried about is overcooling with the fans and snuffing the cat.

Really, we don't run the fans unless trying to bring up a cold soaked house in a hurry. On low speeds the fans are pleasantly quiet so that's about as high as they go. High speed is for chimney fires, runaway stoves, accidental overfires, and if you are not wanting to hear your wife nag.

 

[johnstra]

I wouldn't worry at all about the cat meter going way high. I guarantee mine went higher before I discovered my t-stat was foobar and now that the problem is corrected the stove runs like a champ. I haven't seen any ill effects of mine running too hot for a few loads.