Blaze King... Cat temp when burning low

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johnstra

Feeling the Heat
Hearth Supporter
Sep 6, 2010
334
Northern Colorado
I'm still learning how to burn low and slow and I need some input. I haven't had any trouble burning 24-30 hours right now, but this week is warm so I'm shooting for a 40 hour burn. If I set my t-stat much below 1.5, my cat will eventually (after 7-8 hours) drop out of the active zone. At just barely under 1.5 it seems to hold it's own, but it generally stays way down close to the lower edge of the active zone. A few questions for BK burners...

What do you typically see when you burn with the flapper all the way closed? Will it maintain a burn (cat stays active) till the load is fully consumed?

What do you do if the cat drops below active? Do you bump up the t-stat, leave it alone, something else?

Will burning way low in the active zone hurt the cat?

I'm in Northern Colorado at about 5200' and I have 16 feet of chimney. It could be that my configuration doesn't quite allow me to burn a full load with the flapper closed - just not enough oxygen. I want to find a good spot on the dial for long, slow burns and know that I'm not hurting the cat by burning too low.

Thanks
 
Well that's a lot of questions..lol.

Here's what I want you to do.
Pull the cover off and now and then check out the flapper position..you will catch on as to why.
I never use the cover anymore.

Anyways if i load her up good the cat will glow bright orange-red for maybe 5-6 hours...then tapper off.
That said there have been times where that happened for over 8 hours.
Of course like we all know the wood can and will make a diff. How dry it is..what types and so on.

Anyways when the flapper is closed there is a hole below it that supplies air.
You could make that hole a little bigger if you think your idle air is to low...might be a pain to try and do though and if you made it too big that would not be good.

If your on the downside of peak burn it won't hurt the cat if it's temp drops in increments.
A stall is a diff deal.
 
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What are you burning? With this pleasant weather, I'm going 24 hrs. on Aspen and I'm fine with that.
What 'HotCoals' said, take the cover off of the T-stat. I don't even pay attention to the dial anymore, just look at the air gap on the flapper and adjust from there. 40hrs. sounds good, but not enough usable heat to get through the night most of the time. Soon, I'll be back to loading every 12 hrs. I'm already ready for spring.:(
 
I've had the cover off for a while now. At 1.5 the flapper does gradually creep open and when it does the cat does heat back up, but sometimes it'll get into the inactive zone before the flapper opens. At 1.25 I don't think the flapper ever opens and it'll eventually stall.

I mis-stated in my original post, though. The first 24 hours of the burn are fine if I set it just shy of 1.5. For 5-8 hours the cat is well into the active zone and cat glows, brightly at first and then gradually dimmer. After that the cat will go dark but stay active. It will glow on and off. It's after about 24 hours that it starts to flirt with the inactive range.

I'm not going to mess with the idle-air port. That's asking for trouble.

I'm burning lodgepole pine that's 10-15% on the moisture meter.
 
BK where do you set the flapper for a 24 hour burn? Do you dial down till it closes or leave it open a bit?
 
I've had the cover off for a while now. At 1.5 the flapper does gradually creep open and when it does the cat does heat back up, but sometimes it'll get into the inactive zone before the flapper opens. At 1.25 I don't think the flapper ever opens and it'll eventually stall.

I mis-stated in my original post, though.
The first 24 hours of the burn are fine if I set it just shy of 1.5. For 5-8 hours the cat is well into the active zone and cat glows, brightly at first and then gradually dimmer. After that the cat will go dark but stay active. It will glow on and off. It's after about 24 hours that it starts to flirt with the inactive range.

I'm not going to mess with the idle-air port. That's asking for trouble.

I'm burning lodgepole pine that's 10-15% on the moisture meter.

Heck you're doing good then//probably better then me!
 
I swear all of our T-stat springs are screwy.
I haven't touched the dial since last night, the flapper was lightly closed at that point. Stove was cruising and the fans were on low. This morning, CAT temp was still at 1200 so I didn't mess with it and went to work. I just checked- dial reads about 1.75 and the flapper is open about 3/16". CAT probe reads 300, stove top is about 210. I'll be re-loading here shortly. But heck, 24 hrs. on Aspen, house @ 74::F, I'm not complaining.
I'm a little higher than you (8200'), and my stack is a bit taller, but not much.
If you want to try an experiment, buy some Lodgepole slab wood. Pack the stove full, every nook and crannie, the tighter the better. A load of that burns forever, just not a lot of heat, but comfortable.
 
I swear all of our T-stat springs are screwy.
I haven't touched the dial since last night, the flapper was lightly closed at that point. Stove was cruising and the fans were on low. This morning, CAT temp was still at 1200 so I didn't mess with it and went to work. I just checked- dial reads about 1.75 and the flapper is open about 3/16". CAT probe reads 300, stove top is about 210. I'll be re-loading here shortly. But heck, 24 hrs. on Aspen, house @ 74::F, I'm not complaining.
I'm a little higher than you (8200'), and my stack is a bit taller, but not much.
If you want to try an experiment, buy some Lodgepole slab wood. Pack the stove full, every nook and crannie, the tighter the better. A load of that burns forever, just not a lot of heat, but comfortable.
So did the flapper open some when the stove cooled?
 
I have the princess insert. Where is this flapper you are talking about? Can I access it?
 
I have the princess insert. Where is this flapper you are talking about? Can I access it?
Not unless you pull your stove out..sorry.
 
HotCoals, the flapper did open as the stove cooled. Last night, the flapper was gently closed. I did not check tension this morning, but it seemed to be in the same location. Tonight, it was open when I checked. It seems to operate as it should, tension to keep it closed when hot, then releasing that tension and opening up as the stove cools.
Seems odd to me at times, people report running .5 on the dial when I'm running 1.75 and it's apparently working.
 
My probe doesn't have numbers on it. 300 is no longer active, right?
 
HotCoals, the flapper did open as the stove cooled. Last night, the flapper was gently closed. I did not check tension this morning, but it seemed to be in the same location. Tonight, it was open when I checked. It seems to operate as it should, tension to keep it closed when hot, then releasing that tension and opening up as the stove cools.
Seems odd to me at times, people report running .5 on the dial when I'm running 1.75 and it's apparently working.

Interesting.

With my stove even in the cold months I always turn my all the way down after things are settled in.
I never count on the t-stat to do anything.
That said the temp differential acts as my t-stat.
Glad to hear there is at least one out there that is not so lazy! lol.
It's not that mine don't work..it does..it's just a dollar short and a day late.
 
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My probe doesn't have numbers on it. 300 is no longer active, right?

I think cats are supposed to be active down to 500 degrees...which would be about 250 stove top near the cat...and maybe they are when new.
 
Correct, 300 is below the active line. Pick up one of those Condars with the degree markings, I like those better than the inactive/active/too hot gauges that came with the stove.
 
Mine seems to run best right around 2. A little less is good for warm days. The best I made this fall was 36 hours. Now its a little colder and I am refilling every 16 hours. I don't really pack it up full though, just a nice sized load and this keeps the house around 78 (2000 sq. feet above ground.).
 
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johnstra, also, with our dry wood, depending on the scenario, the CAT gauge may only read 400, but when you engage the by-pass it may take off quickly. I've read of about a 10 min. delay between dial temp. and actual temp. Our delays are shorter.
Here's what I do - T-stat on full (dial all the way clockwise) and let that go for a bit. I keep an eye on the probe in the flue, if that gets to about 500, I cut the air back. By the time I check it again, the flue is about 5-600, and the CAT probe has gotten close to active, or in the active range (500). Once I close the by-pass, the flue temps. stabilize and the CAT just gets hotter. I set the T-stat accordingly. Turns out- 1.75 may be my sweet spot with Aspen, and this stove. Pine will be different, I promise.
 
Thanks everybody for your input. I'm satisfied my stove is running as it should be. It feels kinda silly to be fussing with getting more than 24 hours out of a single load of pine, but I tend to be obsessive ==c I have about 3/4 cord of hardwood (mostly red oak and some honey locust). When it gets cold I'm going to throw and load of that in and see how it does.
 
I've done 40+ hours, actually 48 a couple of time, but that was with really dry oak. A lot of it, big blocks and little pieces stuffed in every corner. I guess just because I could. The novelty of that is worn off, and I look for 12 and 24 hour cycles, depending on the weather.
 
Thanks everybody for your input. I'm satisfied my stove is running as it should be. It feels kinda silly to be fussing with getting more than 24 hours out of a single load of pine, but I tend to be obsessive ==c I have about 3/4 cord of hardwood (mostly red oak and some honey locust). When it gets cold I'm going to throw and load of that in and see how it does.
Once my cat is stalled I just reload, I'm not getting 24 hours but 14-16 hours is fine by me, there's usually hardly any wood left at that point anyway.
 
Seems everybody is a bit different with their t-stat settings. With my Princess last year I got 24 hour burns at 1.5-1.75 and she usually stayed active til the last few hours. If I went lower it would stall or be inactive sooner.
 
The newer cat probe meters that have no numbers, they have little white ticks around the edge of the dial. Look for them. They appear to correspond with 500 degree increments when compared to a labeled meter. I recall BK saying that the labeled cat meters just caused trouble with owners obsessing about what temp their cat was running at instead of only worrying about whether it was active or not which is the important thing.

I have stalled my cat. Just this year. It is much easier to do when outdoor temps are higher and draft is weaker. You can't miss it, the glass will fully get coated, the smoke will become white and heavy, and stove temps plummet.

I'm playing the game of trying to get long burns, low output, AND cleanish glass. Tough to get all three until the weather cools some more. My solution is partial loads, 20 hour burns at a higher stat setting until I can use more heat. Going through way too much kindling.
 
well, I had to baby it a bit by playing with my t-stat during the burn but I reloaded at 7:00 this morning on enough coals to start the new load. The cat was not active but the stove was warm and there were plenty of coals. So that load of lodgepole pine went 47.5 hours.
 
Wait!! 35.5 hours rather than 47.5... I lose track of morning and evening ;em

Still not bad for a load of pine.
 
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