6 or 8.... fit for a King?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

bigbluebus

New Member
Jan 8, 2011
44
Northern IL
I know that the BK King model is supposed to have an 8" flue but I currently have a 25' 6" insulated class "A" metal flue (just a couple months old).

I've read some posts here about people that have a King with a 6" chimney and have no issues.

I don't want to alert the Chimney police, but I really want to understand why the absolute requirement for the 8" setup. Please take into account I have a good draft, straight up through the roof in a 2-story house with stove on main floor AND no elbows or offsets.

SETUP: Double-wall stove pipe inside the family room with flat 18' ceiling (15' black pipe 22ga), insulated Silkerk class A in the attic (3') and insulated Silkerk class A above the roofline (7'), SS chimney cap.

Due to my climate, I can get away with the Princess model which I can "legally" hook up to my 6" flue; but I really want the King for several reasons: the extra deep firebox so I can fit bigger logs, not worrying about logs falling out, not getting my hands or arms burned in the smaller firebox, longer refilling intervals, longer burn times, etc. The stove would MOSTLY be run on minimum setting anyhow. And I've also read that a 6" flue will draft more than an 8" (not tested it myself).

Now that you know my installation setup exactly, does anyone have a good scientific argument why I should redo my setup, that is practically new and replace it with 8"?

Thank You!
 
John,

The Hearth/chimney police will require 8", so will your building inspector. With that said, I've been running mine for close to a couple years now with 6" (adapter right at the stove) x 35'+ chimney. I have two 90's in mine, first about 2', a ~30" horizontal run, then to the second 90 (a tee), and the straight up... all insulated. I have had zero issues with my setup. You MIGHT be able to talk to your building inspector (I'd call) and see if he'd sign off on okaying the 6" since you have a long run, he might be okay with that given the excessive draft you can generate with a long run of 6". Again, I've had no problems at all with mine.

As long as you're heating more than about 1200 sf, I'd go with the larger stove if you can. The only issue I've seen with mine is I can't always turn the stove WAY down w/o the cat going inactive, but a lot of that has to do with the wood being burnt. Even so, I have no problem at all doing 24+ hour burns with the stove set on a med-low burn. You're not going to heat 3000 sf in Jan. at this setting, but I can heat my place nicely at this setting in more mild weather. Normally in the heart of winter I fill the stove twice a day (due to my schedule), and have no problem doing the 8 hour overnight burns (3/4 of a load) and 16 hour day burns (full load) with some wood left over and still cooking when I reload. I have an odd setup (stove in basement, heating part of basement, all of the first floor, with the second and third floor just closed off), so my sf numbers will mean little to you... but probably close to a 1500 sf house with fairly poor insulation in CT.

BTW, I love the stove and wouldn't consider anything else if I had to do it again.

Best of luck with whatever you decide...
 
I've researched and questioned this intensely, to the annoyance of some. :)

BK has not responded to my identical questions on this topic, and their manual for the King says something like "An 8" flue is required unless a smaller one is approved by your local inspector." In other words "Not responsible, you're on your own."

So I did much investigating and calculating, and the only significant risk I found is greater smoke rollout on reloads. This is because a 6" flue only has about 50% of the air flow of an otherwise identical 8" flue with the door open.

And a taller 6" flue won't do much to make up the flow difference. Here are some calculations:

6" versus 8" pipe diameter considerations.

height/dia/insidetemp/outsideTemp/DraftPressure,N/m^2/flow,ft^3/min:
14/8"/68/20/5.2(0.02 water")/164
24/8"/68/20/8.7(? water")/219
14/6"/68/20/5.2(0.02 water")/88
24/6"/68/20/7.3(? water")/103
Blaze King King specifies minimum 0.02" water minimum draft

This assertion is supported by VC, who says a 6" or 8" flue can be used on one of their stoves, but it can't be burned with the door open with a 6" flue.

So the bottom line is a risk of smoke spillage on reloads, and risk your insurance won't pay if you have a claim.

HTH, and good luck.
 
Not sure I can agree. I heat a bit over 1400 sq ft and I find the Princess is almost too much stove in all but the coldest temps (-20*). I have to run the stove really low if the temps are mild, like in the high 20s or the house will easily hit 80-85*. In fact I have no problem heating house and garage which is right around 2100 sq ft. combined.

Wet1 said:
John,

As long as you're heating more than about 1200 sf, I'd go with the larger stove if you can.
 
NATE379 said:
Not sure I can agree. I heat a bit over 1400 sq ft and I find the Princess is almost too much stove in all but the coldest temps (-20*). I have to run the stove really low if the temps are mild, like in the high 20s or the house will easily hit 80-85*. In fact I have no problem heating house and garage.

Wet1 said:
John,

As long as you're heating more than about 1200 sf, I'd go with the larger stove if you can.

From what I see, the output ratings of the stoves are nearly the same, the main difference being firebox size. Is that true?
 
i was wondering the same thing. I thought i saw in the brochere that you could, while not recommended, use a reducer and a 6" pipe but i may be mistaken and it might be for the Jotul or something else i was also looking at. I don't want to replace my 6" double wall pipe thats outside. I think it would be a PITA to do it again, bedides I'd have to replace the thimbal through the wall meaning I'd have to tear down one area cut out/enlarge the hole in the concrete wall and rebuild around it. Nope, think I'd use a reducer first thing coming right out of the box.

jmho

cass
 
tcassavaugh said:
i was wondering the same thing. I thought i saw in the brochere that you could, while not recommended, use a reducer and a 6" pipe but i may be mistaken and it might be for the Jotul or something else i was also looking at. I don't want to replace my 6" double wall pipe thats outside. I think it would be a PITA to do it again, bedides I'd have to replace the thimbal through the wall meaning I'd have to tear down one area cut out/enlarge the hole in the concrete wall and rebuild around it. Nope, think I'd use a reducer first thing coming right out of the box.

jmho

cass

To you and BigBlueBuss, it seems worthwhile to try if the pipe is already installed, especially if someone else is doing the trying. :). I know a guy who has spillage with the King on a 6" pipe, but his chimney is about 14' with a couple of 90s. Still, he's happy with it.

I haven't heard of any safety issues with a correct 6" pipe, so if you don't have a spillage problem...

If you do try, please let us know how it works out.
 
High burn is about the same but low burn the princess is 6400 btu/hr vs 8400 btu/hr for the king.
Burn time is 20hrs for princess and 40hrs for the king.

Of course those are "ideal" numbers, but I can get 16hrs out of a load of wood and have enough coals to not have to fuss with getting wood to catch.
 
NATE379 said:
High burn is about the same but low burn the princess is 6400 btu/hr vs 8400 btu/hr for the king.
Burn time is 20hrs for princess and 40hrs for the king.

Of course those are "ideal" numbers, but I can get 16hrs out of a load of wood and have enough coals to not have to fuss with getting wood to catch.

Good point, I hadn't thought about the low end--thanks Nate. It's great to hear how well those stoves heat. :coolsmile:
 
(Curious) George said:
Good point, I hadn't thought about the low end

Unless you live in Alabama in a house built for Alaska, 6400 vs 8400 isn't going to matter very often.
 
It might be worth your while to give your local building inspector a call and see if they care. You'll probably have some smoking issues with the door open, but maybe not.

We actually would love to have the King model too, but we have a 6 inch chimney. Oh well.
 
Well like I posted, I find the Princess is almost too much stove for my place... so it's something to consider. My house is not super insulated, just min building code, so it's not like I am able to heat it with 3 or 4 candles or something.
I understand if you have an old house with little to no insulation needing to run a stove pretty hot, but with anything built in the last 20-30 years it should be insulated at least semi-decent if min codes were followed.

For me, if it's warmer than mid 30s I end up just running the stove maybe once a day if that. If I try to do a 24/7 burn I have to run it so low that the wood just won't burn well (so low of a draft) and it doesn't take much to get smoke in the house. Not to mention it easily will hit 85* in the house.

Even when it was -20* a few weeks ago, full loads in the stove and it set to #1 was plenty enough to keep the house at 75*

SolarAndWood said:
(Curious) George said:
Good point, I hadn't thought about the low end

Unless you live in Alabama in a house built for Alaska, 6400 vs 8400 isn't going to matter very often.
 
cmonSTART said:
It might be worth your while to give your local building inspector a call and see if they care. You'll probably have some smoking issues with the door open, but maybe not.

We actually would love to have the King model too, but we have a 6 inch chimney. Oh well.
Can you explain why you would prefer to have a King? Is the Princess not producing enough heat output for the area you're heating or is it for the longer burn time (or other reasons?) Please elaborate.
 
the two big selling points with me are the giant fire box-load capability and the thermostat burn enabling long burn times. I like the idea of being able to feed it once a day. I know many of these advertise longer than they really burn. Or, they advertise "X" number of hours of heat derived from a burn. While everyone for the most part talks well of their stove, those that have the BK seldom seem disapointed.

cass
 
NATE379 said:
Well like I posted, I find the Princess is almost too much stove for my place... so it's something to consider. My house is not super insulated, just min building code, so it's not like I am able to heat it with 3 or 4 candles or something.
I understand if you have an old house with little to no insulation needing to run a stove pretty hot, but with anything built in the last 20-30 years it should be insulated at least semi-decent if min codes were followed.

For me, if it's warmer than mid 30s I end up just running the stove maybe once a day if that. If I try to do a 24/7 burn I have to run it so low that the wood just won't burn well (so low of a draft) and it doesn't take much to get smoke in the house. Not to mention it easily will hit 85* in the house.

Even when it was -20* a few weeks ago, full loads in the stove and it set to #1 was plenty enough to keep the house at 75*

SolarAndWood said:
(Curious) George said:
Good point, I hadn't thought about the low end

Unless you live in Alabama in a house built for Alaska, 6400 vs 8400 isn't going to matter very often.
I don't yet own one so here it goes:
Is it possible instead of loading it fully and turning the dial way low, would it be better to just load it less-than-full (say half) and turn the dial a tad higher so the wood burns better and not have the cat working so hard to clean up so much smoke? Am I thinking this correctly? Also, would the burn time be lower in the second situation? if so, would I get 8-10 hrs vs 16? This way I think we could get a lower heat output on not-so-cold days, correct?

Either way, the area I will be heating is over 2400 sq.ft. and the family room the stove would be in has an 18' flat ceiling and a large wall of windows in Northern Illinois climate; that's why I'm thinking I may need the king. I found a dealer (300 mi. away) that said I could take home the Princess and try it out in my house, and if I feel it's not suitable, he would swap it for a King (I would pay the price difference of course).

But I looked at a stuffed Princess picture below and I think that firebox is just very small.

In the other picture below can anyone tell if that is an empty King or Princess firebox?
Also, would it be advantageous to line the firebrick all the way up, instead of just halfway up?
 

Attachments

  • princess-firebox-1.jpg
    princess-firebox-1.jpg
    80.5 KB · Views: 270
  • king-firebox-2.jpg
    king-firebox-2.jpg
    85.8 KB · Views: 229
  • king-firebox.jpg
    king-firebox.jpg
    64.5 KB · Views: 249
bigbluebus said:
In the other picture below can anyone tell if that is an empty King or Princess firebox?

I think that must be a Princess.
 

Attachments

  • BK reload time.jpg
    BK reload time.jpg
    140.4 KB · Views: 198
bigbluebus said:
cmonSTART said:
It might be worth your while to give your local building inspector a call and see if they care. You'll probably have some smoking issues with the door open, but maybe not.

We actually would love to have the King model too, but we have a 6 inch chimney. Oh well.
Can you explain why you would prefer to have a King? Is the Princess not producing enough heat output for the area you're heating or is it for the longer burn time (or other reasons?) Please elaborate.

Well it's simple. We live in a cold climate in an old New England farmhouse. Insulation is pretty poor and the increased wood capacity would give us the option of putting out more BTU's per hour, for longer. The Princess does the job, but the King would do it better. I usually tell my customers if they can do the King, get the King.
 
Status
Not open for further replies.