BK King40 initial impression & questions

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SterlingSL

Member
Nov 4, 2010
57
Dallas Tx
I posted here a while back inquiring if the King40 was overkill for our N. Texas home. We finally got our King40 installed mid-January (ordered in Sept), so I've had a few weeks to use it and get some initial thoughts. It's for sure not the overkill heating beast that I thought it might be from my reading. My only comparison is from our former smaller house (2000sf) with our Regency I3100 insert which had a lower cathedral roof height (11ft) in the main living area where both of these stoves are located. That non-cat stove could get the living area up to 85 on the coldest of days, not that we ran it that high on purpose.

Our current home is 2700 sqft but we're closing off the back bath and two bedrooms and my office so it's probably closer to 2100sqft with the doors sealed off BUT the height of the living area is probably 1.5x the former house. We have some 'big ass' fans up there doing reverse circulation. I was almost considering we needed the smaller version Princess since I'm in Texas and so glad I didn't make that mistake. This King40 can barely keep the house at 70 on a 'warmer' days. Today it's a very non-typical 24 degrees outside and the temp along the wall directly in the warm air down-draft from one of the big ass fans is 67 degrees which I consider 'cool'. We're both running around in layers instead of shorts and t-shirt like we did at the old house with the Regency.

Maybe I haven't learned how to use the stove properly which is highly likely. Questions:

- Cat thermometer: I don't like to run it too high and anytime the cat thermometer runs off the hot end of the gauge, I turn the stove down. This usually happens if I'm not running the carpet blower off to the side (see next question). What is too hot on the cat thermometer? When I was learning this stove, I accidentally let it run to the 6 o'clock position, well off the high end of the active range.

- Blower option: the blower did not come in with the stove so I have been using a carpet blower about 4 feet off to the side to push air off the stove. This seems to help keep the cat thermometer running around 12 o'clock. I also read in another thread the BK blower option is under-powered. Is this really the case? Am I better off running my own blower (wife really hates it). The blower on our Regency was awesome, it would fill the whole living room with heat quick.

- Glass: I cannot keep the glass clean no matter what I do. And cleaning it is a major PITA. For some reason the soot gets stuck to this glass and a razor blade is a lot of work to get it off, forget using glass top stove cleaner like I did with the Regency. I used to hit the glass with that polish/cleaner and the glass would come clean immediately. Not sure what the trick is on this stove other than never clean it again and pretend its an all-metal stove. I may be running it too low as I want to make sure the damn thing is still hot enough by morning that I haven't been running the cat in inactive range.

The wood I'm using is live oak that I split two summers ago and is consistently testing at ~15% moisture content.

I'm all ears, open to suggestions. I really want to know if I should pursue getting the blower option added. We really hate having to use a stupid carpet blower sitting on the wife's living room table.



Stove01.jpg

This is what I get to look at :( The scrapes are an attempt to get the glass cleared with a blade scraper.

StoveGlass.jpg
 

Highbeam

Minister of Fire
Dec 28, 2006
19,993
Mt. Rainier Foothills, WA
It's appears that you are not running that thing hot enough at all. Either because your wood is wet or because you are afraid of turning it up. If you need more heat, turn it up. Don't worry about the cat meter other than to be sure that it is above the active line. I should mention that you should verify that your door gasket is snug which is just normal maintenance but since you'll be cranking it up you want this thing to work as designed.

The carpet blower isn't doing much for you since this model is heavily shielded on the sides. The BK blowers move air between the layers of steel against the actual firebox and will help but this is minor compared to you turning up the thermostat. You're stuck in second gear.

Your home is huge. Even 2100 SF with double tall ceilings is like 4200 SF of regular house. All of those fans could make it feel cold too. If need be, you can run the central furnace to supplement. Not everybody can heat 100% with a single woodstove. If that king can't do it when running hot then only a couple of others might do slightly better.

Once you get the stove to run hot, the glass will self clean. Even running on low settings like I do, only the bottom corners get that bark accumulation. The middle and top stay clear which tells me that you are majorly hobbling that stove.
 

DuaeGuttae

Minister of Fire
Oct 26, 2016
1,452
Texas
I have never run a BK (though I did briefly own one before I found out suddenly that we were moving). I’ve read a lot of threads, so I’ll put here the advice I’ve seen in them from actual BK owners.

First of all, “Welcome to the dark side.” That’s a common line that is said to King and Princess owners because of the black deposits that build up on the glass. Embrace it. Parts will burn off during a high burn, but it won’t be as clean as your Regency used to be.

Secondly, the cat gauge has one sole purpose as I understand it: solely to tell you if the cat is active or inactive. It isn’t necessarily correlated to a thermometer with the same size. If the needle runs over the active end (which is it wont to do in the beginning when cats are hyperactive), that is not any indication of overfiring. The thermostat on the BK is designed to close to prevent actual overfire temperatures, so feel free to turn it up for maximum heating without worrying what the needle shows.

If you pack that stove full of split and dried live oak, my oh my, you should be cranking out the BTU’s. If the King really can’t heat that place, I’d be thinking that it has more to do with the house (construction/insulation/air sealing/leaks/cubic footage) than with the stove itself.

I’ll let other people address the blower question. I think @showrguy runs a King and may be able to give you some good information.
 
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Nealm66

Minister of Fire
Sep 25, 2020
1,365
Western Washington
Try turning it up and turn the ceiling fans off. I have 12/12 roof and found turning the ceiling fans off really makes a difference. It takes a while to figure the setting that works. I made a mark on mine and only change it in the extremes
 

showrguy

Minister of Fire
Aug 2, 2015
569
Marysville, Pa.
I have never run a BK (though I did briefly own one before I found out suddenly that we were moving). I’ve read a lot of threads, so I’ll put here the advice I’ve seen in them from actual BK owners.

First of all, “Welcome to the dark side.” That’s a common line that is said to King and Princess owners because of the black deposits that build up on the glass. Embrace it. Parts will burn off during a high burn, but it won’t be as clean as your Regency used to be.

Secondly, the cat gauge has one sole purpose as I understand it: solely to tell you if the cat is active or inactive. It isn’t necessarily correlated to a thermometer with the same size. If the needle runs over the active end (which is it wont to do in the beginning when cats are hyperactive), that is not any indication of overfiring. The thermostat on the BK is designed to close to prevent actual overfire temperatures, so feel free to turn it up for maximum heating without worrying what the needle shows.

If you pack that stove full of split and dried live oak, my oh my, you should be cranking out the BTU’s. If the King really can’t heat that place, I’d be thinking that it has more to do with the house (construction/insulation/air sealing/leaks/cubic footage) than with the stove itself.

I’ll let other people address the blower question. I think @showrguy runs a King and may be able to give you some good information.
I can’t add much more than has allready been said, but..
my house is 40x60, 1st floor, 40x80 2nd floor, pretty open floor plan with alot of open space a full 2 floors, I have a pair of 72” BIG ASS FANS in the great/stove room.
I do have the fan kit, but never really used em untill this past January (I think it was the coldest Jan. on record..)
my stove has NEVER been set to the 6 oclock setting other than startup/reload..
Normal setting for me is right about the 3:15 setting on a clock face..
Been running since 2015, replace CAT about every 2 1/2 years..
OAK made a noticeable difference in my place, as far as drafts go.. Others say “not so much”..
Could not possibly ask more out of a stove than what this thing does..
Oh, I’m in central Pa. It gets damn cold here at times..
 

Tar12

Minister of Fire
Dec 9, 2016
1,824
Indiana
I do not know if the same fan set up are used on the King and Princess but I have the fans on my Princess..they do indeed move some air...I rarely run them due to the fact they will easily run the stove room temp above 80 ..I debated getting the fans initially but I am oh so glad that I did! Like yourself we had a late stove install...just in time for the worst arctic blast that I have experienced with minus single digit highs and brutal wind chills..with out the fans running the stove struggled to maintain in the mid 60s...the fans bumped that up to the low 70s..the fans are worth the investment...and as others have stated you are not running that stove hot enough..I run my stove on the warm side and very seldom will I have much if any black on the glass..and i never scrape the glass...I will allow the stove to cool and will spray on some MEECOS Red Devil Woodstove glass cleaner..nothing I have tried out performs it!


WtsV4u1l.jpg

vnDFiY5l.jpg
 
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ohlongarm

Minister of Fire
Mar 18, 2011
1,606
Northeastern Ohio
It's appears that you are not running that thing hot enough at all. Either because your wood is wet or because you are afraid of turning it up. If you need more heat, turn it up. Don't worry about the cat meter other than to be sure that it is above the active line. I should mention that you should verify that your door gasket is snug which is just normal maintenance but since you'll be cranking it up you want this thing to work as designed.

The carpet blower isn't doing much for you since this model is heavily shielded on the sides. The BK blowers move air between the layers of steel against the actual firebox and will help but this is minor compared to you turning up the thermostat. You're stuck in second gear.

Your home is huge. Even 2100 SF with double tall ceilings is like 4200 SF of regular house. All of those fans could make it feel cold too. If need be, you can run the central furnace to supplement. Not everybody can heat 100% with a single woodstove. If that king can't do it when running hot then only a couple of others might do slightly better.

Once you get the stove to run hot, the glass will self clean. Even running on low settings like I do, only the bottom corners get that bark accumulation. The middle and top stay clear which tells me that you are majorly hobbling that stove.
What other stoves might do better, just wondering, I've run a King for 8 years now, with 10 foot ceilings and almost wall to wall glass in the stove room and even at -14 2 weeks ago actual temperature I could have heated the place north of 80 degrees easily if I chose to.
I know from a learning curve if you have a BK problem it's usually wood related, the Kings like dry wood, without it come problems such as described here. Just my take no expert by far. My house layout is 1900 sq feet 85 feet long .
 
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Highbeam

Minister of Fire
Dec 28, 2006
19,993
Mt. Rainier Foothills, WA
I do not know if the same fan set up are used on the King and Princess but I have the fans on my Princess..they do indeed move some air...I rarely run them due to the fact they will easily run the stove room temp above 80 ..I debated getting the fans initially but I am oh so glad that I did! Like yourself we had a late stove install...just in time for the worst arctic blast that I have experienced with minus single digit highs and brutal wind chills..with out the fans running the stove struggled to maintain in the mid 60s...the fans bumped that up to the low 70s..the fans are worth the investment...and as others have stated you are not running that stove hot enough..I run my stove on the warm side and very seldom will I have much if any black on the glass..and i never scrape the glass...I will allow the stove to cool and will spray on some MEECOS Red Devil Woodstove glass cleaner..nothing I have tried out performs it!


WtsV4u1l.jpg

vnDFiY5l.jpg

Is your stove burning on top of 2x4 lumber and bare wood subfloor? Glass looks clean.
 

Highbeam

Minister of Fire
Dec 28, 2006
19,993
Mt. Rainier Foothills, WA
What other stoves might do better, just wondering, I've run a King for 8 years now, with 9 foot ceilings and almost wall to wall glass in the stove room and even at -14 2 weeks ago actual temperature I could have heated the place north of 80 degrees easily if I chose to.
I know from a learning curve if you have a BK problem it's usually wood related, the Kings like dry wood, without it come problems such as described here. Just my take no expert by far. My house layout is 1900 sq feet 85 feet long .

Open up the EPA list and sort by btu output. Most are higher than the king but as we BK owners know it's a tortoise and hare scenario. The BK can keep that higher output up for a long time.

The king is a hoss but the top end of the EPA listed output range is just 35k btu which is actually pretty low. I'm sure BK will have a reason for this such as testing differences or luck or whatever. It's sad because we know that a 4.3 cubic foot monster at 800 degrees is making a lot of output.
 
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Tar12

Minister of Fire
Dec 9, 2016
1,824
Indiana
Is your stove burning on top of 2x4 lumber and bare wood subfloor? Glass looks clean.
It is...I unhooked the stove and tore out the old hearth and i am having a custom hearth installed starting tomorrow...
 
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ohlongarm

Minister of Fire
Mar 18, 2011
1,606
Northeastern Ohio
Open up the EPA list and sort by btu output. Most are higher than the king but as we BK owners know it's a tortoise and hare scenario. The BK can keep that higher output up for a long time.

The king is a hoss but the top end of the EPA listed output range is just 35k btu which is actually pretty low. I'm sure BK will have a reason for this such as testing differences or luck or whatever. It's sad because we know that a 4.3 cubic foot monster at 800 degrees is making a lot of output.
i actually saw the Pacific energy T6 puts out more than a King , but for how long.
 
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stoveliker

Minister of Fire
Nov 17, 2019
6,200
Long Island NY
Having only browsed the other replies, let me give some reasoning for the suggestions you got.

The low heat output AND black window suggests that not enough heat is produced. Either because byou are not running it hot enough or because your wood is wet (leading to a stove that is not hot enough). It's quite easy to have a clean window, and not having that is directly related to not having enough heat.

So, dreaded question: how do you measure your moisture content? Precisely, step by step?

The cat gauge is only meant to tell you when it's ok to close the bypass. No other info should be inferred from it.
 
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SterlingSL

Member
Nov 4, 2010
57
Dallas Tx
So, dreaded question: how do you measure your moisture content? Precisely, step by step?

The cat gauge is only meant to tell you when it's ok to close the bypass. No other info should be inferred from it.

All of my wood is currently in splits. I split one of those and place the prongs along the grain in 2-3 places down the split (vs across the grains). Not sure if this is correct or not.

Sounds like part of my problem is rely on the cat gauge to determine where I keep the dial. On the Regency it was all about watching the temp gauge mounted just above the door and keeping it in a certain range. Sounds like that's not the intent of the cat gauge here. Do others use a gauge somewhere else on the KE40?

I haven't replied to anyone else here as I got a huge amount of replies which I'm thankful for. I jsut need to go back and re-read at least 4-5 times every post and soak it all up. I think I really need that damn stove fan, wished it would have come in with the stove. I did order one.
 
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stoveliker

Minister of Fire
Nov 17, 2019
6,200
Long Island NY
Moisture content seems ok then. Good!

Yes, a flue probe, 18" above the stove. Look at the condar store. Other brand is ok too. Not the magnet one but the one that sticks into the pipe.

The cat gauge is indeed not meant for how you have used it.
 

Stump shot

Member
Jan 15, 2014
67
Montana
The fan kit will help greatly to heat your home when it is cold out.
 

Tar12

Minister of Fire
Dec 9, 2016
1,824
Indiana
Here is a link to the Condar Flue probe that stoveliker speaks of...for double wall pipe..

If you want even more precision the Auber 200 is a excellent choice and it also has a audible alarm that goes off once it hits the preset temp limit...perfect for when you have a absent minded moment! I am hard of hearing and found that the built in alarm is a little weak for me(my wife hears it just fine) and installed the external alarm..you wont miss hearing it! lol..


Both options require drilling a small hole..
 
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Tar12

Minister of Fire
Dec 9, 2016
1,824
Indiana
Here is a picture of both of them in operation...the Condar runs 100 degrees cooler than the Auber...I have the Auber placed 1.5 inches higher than the Condar on my set up...one thing that irked me about the external alarm is that it came in 2 pieces and you have to splice the wires together?
What the hell is that about? lol...it works properly.

OjIO7Mtl.jpg
 

Highbeam

Minister of Fire
Dec 28, 2006
19,993
Mt. Rainier Foothills, WA
If you want even more precision the Auber 200 is a excellent choice and it also has a audible alarm that goes off once it hits the preset temp limit...perfect for when you have a absent minded moment!

I was waxing skiis in the shop last week during a stove warm up and Queen's Bohemian Rhapsody was playing on the radio and, well, I cranked it up. It's a long song. The noncat shop stove with the auber ran right up to 1050 flue temperatures before I could hear that alarm that is set to go off at 1000. Fortunately, the noncat is very controllable and chopping the air and flue damper brought it down to safe temperatures within seconds but we all have those absent minded moments.

I do value and pay close attention to the flue temperatures above my BK. Depending on fuel, I have found it possible to exceed what I feel is a safe temperature in the flue. I suspect that the OP has never gotten his flue warm enough to burn the paint off. You could confidently operate the BK with just a flue meter honestly. Or nothing in an emergency after some experience.

If double wall, get a probe meter. If single wall you're stuck with a surface meter. Though I have been happy with the auber electronic for single wall since it uses an actual thermocouple to measure the temperature in the flue vs. a coil spring that is calibrated for being on the other side of a double wall flue pipe.
 
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Poindexter

Minister of Fire
Jun 28, 2014
2,815
Fairbanks, Alaska
@SterlingSL , ignore the cat probe once you have the combustor engaged, try running that thing at full throttle until your wife is, umm, sweating and dressed in items that can't be described meticulously here.

1. As long as your fuel is above 12% MC (you are measuring correctly) you aren't going to hurt anything on the stove running wide open throttle. Imagine it is 1969 and you got a new Guard's Red GTO convertible and a Big Mac. Throw that styrofoam container out of the car and mash the throttle with everything you got. Nail that throttle to the floor and go find a beverage to savor while your wife is disrobing.

2. If your wife is still wearing layers when your fuel is burnt down to coals, I suggest you go looking on your exterior walls for air leaks. Windows, doors, receptacles, and switches. Maybe along the baseboard too.

3. On the BK website right now the King will do 47,800 BTUs/hour sustained at full throttle. An Ashford 30.2 can produce 35,900 BTUs/ hour sustained. In 1200sqft with good air sealing I can keep my wife in summer outfits at -50, -55dF outdoor ambient, with our Ashford chewing through cordwood like some kind of hyperactive termite. At 24 freaking above in 4200 sqft, with my A30 and 15% fuel I could have my wife naked as a jaybird in something like 12-14 minutes.

4. Black glass and 15%MC fuel tells me you are NOT running the stove very hard at all. A new combustor is going to be 'hyperactive' for something like 1-2 cords. Have you burnt two cords yet? Three words. Wide Open Throttle. Wherever the top of your swoosh mark is, the highest numbered paint mark, load the stove up, turn the knob to there, and leave it there for a week or two. You aren't going to hurt the stove. Enjoy your beverage.

5. Put the carpet blower away. When the fan kit comes in, install it. In the meantime you could try a regular 20 inch boxfan on the floor at the end of the farthest hallway gently (on low setting) wafting cool air along the floor from the distant bedrooms towards the stove.

6. Your glass is not clean because you are running the stove at such low settings, qv. I keep my glass clean by turning the throttle setting up to wide open in January, and December, and February, and November....

7. What is the BTU rating on your furnace system? Just curious. I spent a winter, I think it was 2007, in Plano, TX as a contractor and I find it hard to imagine a King with fuel at 15%, even in 4200 sqft, is not meeting your needs. January in Plano was kinda like March or September up here.

8. Yes, order the factory blower for the stove. With your sqft you want the fan kit to move the King from a radiant stove towards a convective stove so you can have warm air all over the house.

9. Run it wide open throttle man. You got a warranty, and you got homeowner's insurance. If the stove couldn't take it the mfr would have made wide open throttle a lower setting. Do it. It will be awesome. Just be sure your wife doesn't toss lacey unmentionables directly onto the stove cause they would melt and nothing spoils a mood like a smoke detector alarming.
 
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Poindexter

Minister of Fire
Jun 28, 2014
2,815
Fairbanks, Alaska
As others have already posted, new combustors are 'hyperactive' and will indicate temps above the top of the "active range" for a little while until they settle down. Mostly my new combustors have settled down in the 1.0 to 1.5 cords burnt range. I have had one out of 4 or 5 that didn't settle down until close to 2.0 cords burnt.

The single most important thing is to let the stove heat up into the active range before engaging the combustor. There are some threads here about engaging the combustor early. I have posted my reticence in some, but probably not all, of those threads. Having a new combustor indicate 'overrange' temps I ignore.

The other super handy thing about the combustor temp probe is learning how low in the active zone you/I can let it go and still get a quick, hot reload without a prolonged open bypass door phase.

For me as a 7-8 cord per year burner, my ideal reload is a hot reload, where I can identify the moment, open the bypass door, turn the throttle to high, go pee, (wash my hands) open the loading door, add fuel, close the loading door, count to three, re-engage the combustor, come back in thirty minutes to turn the throttle back, repeat in 12 hours.

I want enough coals for a quick (sub five second) light off and char phase, then 30 minutes of bake and then 11.5 hours of cruise. Y'all remember the wood stove in the relatively recent animated Disney version of Beauty and the Beast? The name of that stove was bouche, a French word for 'mouth.' We were watching that movie one night, the wife and kids and I, and on of the kids said "our stove is fiercer than that, we should name it 'bouche' until we think of something better; and they haven't yet thought of anything better.

I personally have not hurt my BK stove running wide open throttle for months at a time, and I haven't yet read about anyone on the internet who was able to either. Bypass open and loading door cracked open, yes, that moron is going to warp stuff. With both doors closed, these stoves can handle extended (for months) WOT with panache, and then run low and slow in the shoulder seasons without skipping a beat.

Best wishes. Send it man.
 
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Highbeam

Minister of Fire
Dec 28, 2006
19,993
Mt. Rainier Foothills, WA
Lots of new stove owners, of all stoves, are afraid to let her rip. That’s fine if you’re not cold. The stove is happy to lope along on low output.

These things are built with high temp paint for a reason!