Operation question

[reaperman1]

Im still in the learning process of using my new BK. After initial startup or reloading the thermostat is on high. After the new load is up and running I adjust the thermostat lower in increments. What I'm trying to understand is why is the stove at its hottest output when the the thermostat is at the lowest setting. When its turned all the way down, the flames disappear and the cat glows bright orange. At this point the stove is hotter than the previous medium setting and hotter that the highest setting during the charring period. Is it because the wood is off gassing and burning the smoke more efficiently? Later on in the burn on the lowest setting, the cat will stop glowing, at this point when I turn the thermostat up, flames will appear once again. It appears at this stage the higher thermostat setting will output more heat? Am I on the right track?

 

[stoveliker]

How do you know it is hottest?

The cat gauge is not a measure of the total heat output of the stove.

 

[Dieselhead]

The cat gage is installed in the hottest part of the stove. The rest of the stove cools off when you lower the tstat, that cat glows and continues to warm a small overall portion of the entire unit. Run the stove at 4oclock for a while and you want to talk about heat output.....

 

[stoveliker]

Though running on high, the gauge may not be at the hottest part at all...

The cat heat is essentially from what is left over from the burn in the firebox. Running high that may not be as much as when running low (which provides a lot of smoke, aka cat food).

 

[Dieselhead]

Right, overall stove temp vs the small area on top directly above the cat. I can tell the back burns hotter if I don’t rake the coals forward and let the back of the load get going first, I can feel the heat back there and the stat clicks closed at a much higher setting then if I start the load off from the front.

 

[reaperman1]

How do you know it is hottest?

The cat gauge is not a measure of the total heat output of the stove.

True, I havent hooked up my Auber probe yet. However, I do have a magnetic thermo on the dual wall stove pipe up about 1 foot. I realize its not a indication of too much, but there isnt anywhere to put the magnetic thermo on my stove. On a startup the magnetic thermometer stays a constant 200 degrees, after charring the new load for a half hour I will turn the knob down to just above the click which is around the 2:30 position. The cat glows and the magnetic thermometer will rise to around 300 degrees. I admit I'm in the learning stages of my new Boxer and hopefully this weekend I will have time to install the Auber probe. Being the Boxer is a dual walled stove its impossible to get a accurate reading of the outside of the actual firebox. So far its been things are going well. Being the Boxer is a dual walled wood stove it does trap heat between the firebox and the outside surrounding box. To get the max heat from the stove the blower fan is a big help. So far in my findings, I really dont need to run the blower too much unless I want the room really warm. I left the blower on the lowest setting last night for the first time. When I went to bed the living room temp was 77 and I woke up to 81 degrees. I wasnt real cold out last night, I think I had 20 degrees when I got up. Tonight it will get down to 4F, its starting to feel like Minnesota.

 

[Nealm66]

The cat should settle down after a while. I made a mark on my dial that keeps my upstairs around 72 for the most part if using consistent wood. Also a good idea to start looking a day ahead on weather as sometimes small loads can really help with the reload schedule. Hope this helps

 

[Highbeam]

Even if you could measure the stove top temperature there is very little value in that number. There will be a really hot spot over the cat at low settings and then that hot spot expands at higher settings. I tried it and it was silly.

Flue temperatures are much better indicator of burn rate in my experience.

 

[stoveliker]

I don't see much wrong. You can sometimes feel the radiating (IR) heat from the cat if you sit/stand in front of the stove and the cat is really glowing brightly. But that does not mean that the stove is at its hottest - i.e. that the stove is putting out the most BTUs.

How tall is your chimney?

Going from 77 to 81 to me suggests you could have dialed down a bit more (provided you have enough draft so the thing does not stall).

Note that the "click" will be at a higher position (e.g. 2.30) when the stove is hot than what it will be when the stove is colder.
I suggest that the next time the stove is cold (though in MN that might be in April...?) you open the Tstat, and then dial it closed and mark the position where you hear it shut the flapper completely. That will be your minimum. When the stove gets hotter, that position will slowly go to "later times".

(Example: when it's raging hot running at 6 pm, and you dial down to 4 pm, it'll shut the air completely because the stove is hotter than what the Tstat says it should be at 4 pm. That allows it to cool down (without dying on you because of a hole in the flapper), until it is at the temperature that is appropriate for the 4 pm setting, when it'll open a little to maintain that temperature - similar to going 100 mph, and taking your foot off the gas to coast to 55 mph. Once you reach 55 mph, you'll have to press the gas a bit to maintain that new lower speed.)

So, find the "closed" position when the stove is cold. That is your absolute minimum. If your chimney is tall enough (you have enough draft - unlikely not to be the case in cold MN nights), you'll be able to run at or near that setting. See if you can get the room a (to me) more comfortable 70-72 F that way.

 

[reaperman1]

Thanks for the input guys. My chimney is 15’ plus the rain cap, strait up no elbows. It may sound kind of odd. But I’m not really looking for record breaking burn times. In fact, I’m only putting about four 16” splits per load. Thats only a little more than half the stoves capacity. So far that will get me overnight with plenty left to reload before work. Then repeat which will last until I get home in the evening. I think I’m unconsciously keeping the stove hotter than I need to for fear if I turn it too low it won’t output enough heat. For the past 15 yrs I’ve been heating with a wood furnace that needs reloading constantly. In order for the furnace‘s duct fan to output heat the furnace had to run hot otherwise the heat would just go up the chimney. My wood is well seasoned oak and ash so it really puts out the btu’s. That’s another reason I’m a little hesitant to load the stove too full. I‘ve seen a lot of photos of how full users fill their BK stoves to the max. Those are some scary photos, I’m not that brave yet.

 

[stoveliker]

Ok. At 15' you're not having an overly tall chimney. Tall chimneys (and colder weather) often make the (cold) "closed" position be lower because the draft pulls more air thru a small opening.

Given your hesitance (which is fine - better to learn slowly with confidence, than fast with fear), just make tiny adjustments. Next time, go a tiny bit lower and see what happens.

Regarding how full you load the stove - the beauty of a thermostat is that if the big load takes off, it'll just close the air down because the stove gets hotter. In my experience the bigger load is not going to lead to (bigger) problems. People here often compare the firebox of a BK to the fuel tank. Load it up so it lasts longer. The thermostat controls (!) the heat output rate. This is different from many other stoves where you set the size of the air inlet - if the chimney gets warmer, the wind picks up, the outside gets colder, then the draft picks up, and the load will burn more vigorously, creating more heat in the chimney which will make the draft pick up etc. Then you can (in principle) get a runaway.

Here (BK), if the chimney gets warmer, the draft will pick up, more air to the fire, the stove gets warmer, and .... the thermostat closes the air a bit. I.e. it's safe.

However, your burning schedule works with your life schedule now. I'd experiment in small steps with closing the thermostat a bit more (unless you like 77-80 home temps...) and just see what happens. 1/20 of an inch. Small steps. That'll give confidence as it'll not be too different from what you have seen. But doing that a few times will slowly change the heat output rate.

You're already ahead of many with a new stove: you have dry wood. Congrats on that. Prevents a boatload of problems.
Play with the stove, slowly, and you'll get the confidence to operate it according to all its capabilities (this holds for all stoves, not just the BK).

 

[Hoytman]

I take it you BK owners don’t worry about chatting the wood before turning down the thermostat? That would make sense that you wouldn’t have to char the wood because it burns the smoke anyway.

 

[stoveliker]

We do char (bake) the wood before turning down. That is advised by the manual and indeed works way better.

 

[Nealm66]

I wonder if in the long run you’re going to be happier with a 24 hour reload schedule if the 12 hour is pushing you near 80 degrees. I often times will reload lighter at night ( princess model) for more room in the am and 12-16 hour days are no problem but that dial setting keeps my house about 72 in our general living space unless it warms up. It’s not hard to get 20-30 hour burn times but not sure about the boxer?

 

[Highbeam]

I wonder if in the long run you’re going to be happier with a 24 hour reload schedule if the 12 hour is pushing you near 80 degrees. I often times will reload lighter at night ( princess model) for more room in the am and 12-16 hour days are no problem but that dial setting keeps my house about 72 in our general living space unless it warms up. It’s not hard to get 20-30 hour burn times but not sure about the boxer?

I often need to let the fire nearly go out because even on low it's too much heat. The room temp falls to a still comfortable lower 70 range before I bake in the new load and room temps climb to upper 70s where we like it. That's our typical scenario for typical weather which sits near freezing overnight and above freezing during the day.

 

[reaperman1]

How do you know it is hottest?

The cat gauge is not a measure of the total heat output of the stove.

I stand corrected. I hooked up my Auber 200 after work this evening. Once I got thru the crash courses on how to get the alarm to stop going nuts I was able to watch how things play out. During the charring phase with medium yellow flames the temp was rising to nearly 900 ( where I set the alarm). I turned the thermostat to the 3:00 position to settle the stove down before the alarm went off once again. Its in this phase that the stove appears to be burning hotter with the cat glowing brightly and the secondary's putting on a nice show. But the Auber shows the flu temp hanging around 830 degrees range. I'm not quite sure what temps I should be aiming for during normal operation. Feel free to advise me, thanks.

 

[stoveliker]

That does seem high to me. I see up to 650 F running high. (200-300 low).

Given your 15' chimney I'm hesitant to say the following, but high flue temps are often (not always?) caused by draft that's too high.
If you're an engineer (or a person with data gathering habits), see if you can buy a magnahelic or so to measure the draft. Why? Because if it's (too) high (for reasons I don't comprehend given the 15' chimney), adding a flue damper will help - and this help means more heat in your home because less going up the flue.

 

[reaperman1]

I wonder if in the long run you’re going to be happier with a 24 hour reload schedule if the 12 hour is pushing you near 80 degrees. I often times will reload lighter at night ( princess model) for more room in the am and 12-16 hour days are no problem but that dial setting keeps my house about 72 in our general living space unless it warms up. It’s not hard to get 20-30 hour burn times but not sure about the boxer?

I havent had much time to experiment until now its been only 5 days since my maiden fire. I just started a long weekend and my wife is leaving on a trip Saturday. So I have free range to play

 

[reaperman1]

That does seem high to me. I see up to 650 F running high. (200-300 low).

Given your 15' chimney I'm hesitant to say the following, but high flue temps are often (not always?) caused by draft that's too high.
If you're an engineer (or a person with data gathering habits), see if you can buy a magnahelic or so to measure the draft. Why? Because if it's (too) high (for reasons I don't comprehend given the 15' chimney), adding a flue damper will help - and this help means more heat in your home because less going up the flue.

I dialed the thermostat back to around 2:30 and the temps immediately fell to around 410 to where the cat stopped glowing. I'm surprised how fast the Auber reacts to a small changes in the thermostat setting. If my chimney is a bit too tall it would have been nice to know before I dished out $100/ of class A . Actually it would be easy to take a two foot section out if needed. Now I will have an opportunity look for patterns with the help of the probe thermometer. Tonight is the first fire using the probe.

 

[stoveliker]

I wouldn't change hardware at this time. Just play, get a feel for how the stove works with the draft you have. Nothing serious is going on that warrants action regarding chimney now.

If you set the alarm on the auber, you're certainly (reminded of being) safe.

 

[Nealm66]

I would focus on your house temperature. At least that’s the way I did it. It might take a while for the new cat to settle in but you can start stuffing it full and turning it down until you get a decent room temperature and see where your burn time sits. If it’s burning low all the time I’d open it up once in a while to clean things up. Eventually as your confidence grows, definitely make a mark on the swoosh. It makes a good reference. Load the stove to fit your reload schedule and the mark on the swoosh should still keep you around a decent room temperature. Hope this helps!

 

[weee123]

Given your hesitance (which is fine - better to learn slowly with confidence, than fast with fear),

Yea definitely not fun, especially on a noncat stove where things can get really spicy quick

 

[stoveliker]

I don't think that is a cat or noncat risk. It is an active air control (thermostat) on some stoves that mitigates some risk (but does not necessarily mitigate risks associated with install errors or leaks etc).

 

[stoveliker]

Ok. I'll follow but bkvp is much better suited to help, so I'll go silent. Good luck.