Setting up the flue pipe for a new King 40 install: A choice

[corona5k1635]

For an install of a King 40:

Option 1: 8" flue pipe for 3 ft then reduced to 6" flue pipe for 12 ft.

Option 2: 8" flue pipe all the way but with a 30-degree off-set after 3ft.

In both options, the whole system is made of double-wall pipe where about 8 feet of Class A will be exterior above the roof. Living in eastern PA. Which would you choose??

 

[stoveliker]

I'd do 8" all the way.
Is this 12 ft stove pipe plus 8 ft of class A?
For 20 ft a 30 deg offset is not a problem.
Go with the recommended 8". Avoid smoke roll out when you open the door ..

 

[corona5k1635]

No 15 foot total… just barely gonna hit the minimum requirement

 

[kborndale]

The stove is made to run on an 8 inch exhaust, why would you want to reduce it to 6?

 

[corona5k1635]

The stove is made to run on an 8 inch exhaust, why would you want to reduce it to 6?

To avoid crossbeam/truss in the roof

 

[stoveliker]

Id still go with the 8".
You need the volume to transport the exhaust gases. A 30 deg offset is not much. (Far less than a bunch of 90s).

 

[kborndale]

To avoid crossbeam/truss in the roof

Just do it the right way. Reducing from what the stove is made intended to be run on is not the right way.

 

[corona5k1635]

Ok. I guess I will not try to reduce it.

 

[Highbeam]

The king is a great stove but it uses that crazy 8" chimney and is pretty goofey looking like my princess. Have you considered the smaller princess or a prettier 30 box on a 6" vertical flue? That 6" flue will work better for any future stove that almost certainly will not use an 8" chimney.

You just don't see many kings. People don't put performance as the top priority and that 8" pipe is a pain.

 

[corona5k1635]

The king is a great stove but it uses that crazy 8" chimney and is pretty goofey looking like my princess. Have you considered the smaller princess or a prettier 30 box on a 6" vertical flue? That 6" flue will work better for any future stove that almost certainly will not use an 8" chimney.

You just don't see many kings. People don't put performance as the top priority and that 8" pipe is a pain.

I went back-and-forth in making the decision on which one to go with. At this point, I’ve already purchased the king it’s just sitting in my house waiting to get connected to a stack so I hope it works out. Installer is going to add 2-30° elbows to make it work. I’m a little scared that there won’t be enough draft because the manual says to use 18 feet total stack instead of 15 feet in the case if using 2-30s. I figure I’m just gonna have them do 15 or 16 feet and see how it goes and then just add length outside if I get a smokey smell. The issue is when it’s running on low right? When it’s up on high, it shouldn’t matter, but if I want to go low and slow for a long time… It’s gonna need the right draft I think. How does your behave on low?

 

[stoveliker]

Yes, the lower you run (or the warmer the outside weather is), the less buoyant the air in the flue is, and thus the less the draft sucking new air into the stove is.
You'll have to increase the thermostat setting a bit to get the same BTU output then.

You can always add sections of class A on top (bracing needed at 5 ft ). First indication of not enough draft will likely be smoke roll out when you open the door.

Also note that you'll have to find the thermostat setting that is your (weather dependent) minimum. That's different for each install. And the range in which you go from that minimum sustainable (cat remaining active) burn rate to the max will be far less than the full swing of the knob.

Do you have wood that's already been drying?
Oak will need three years split and stacked off the ground. Maple will be good in two.
Pine or for in one season
Buying wood won't ever be sufficiently dry.
You wont like how the stove behaves when it's forced to consume fuel it doesn't like.

Do read the manual before and during operation.
Close bypass when the cat gauge shows active range, never open the door with the bypass closed.
To reload, open bypass, wait a few minutes, slowly open the door, fill,.close the door,.let the fire start (for truly dry wood that's less than a minute), close th bypass if the gauge still shows active, let the fire rip for a bit (15-30 mins), and I'm 3-4 steps separated by 5-10 mins dial down to your desired heat output.

 

[Highbeam]

I went back-and-forth in making the decision on which one to go with. At this point, I’ve already purchased the king it’s just sitting in my house waiting to get connected to a stack so I hope it works out. Installer is going to add 2-30° elbows to make it work. I’m a little scared that there won’t be enough draft because the manual says to use 18 feet total stack instead of 15 feet in the case if using 2-30s. I figure I’m just gonna have them do 15 or 16 feet and see how it goes and then just add length outside if I get a smokey smell. The issue is when it’s running on low right? When it’s up on high, it shouldn’t matter, but if I want to go low and slow for a long time… It’s gonna need the right draft I think. How does your behave on low?

If you have the king already then I too would recommend all 8" and the offset in the stove room with double wall. I don't think the 30 degree offsets will be a big deal and expect good performance on 15'.

My princess is only on 12' of stack which was the minimum required back in 2012 when I installed it. I get no smoke smell and run on low 95% of the time. They, BK, have since increased that minimum to 15'. I bring this up to point out that my princess works great on less than the 15' minimum. I think they added a conservative fluff factor going from 12 to 15. Regardless, give it a shot and if needed you can add more. If I were you I would add at least the maximum you can right now without a roof brace. Oh and don't put a bird screen on the chimney cap unless required by law in your location.

Insufficient chimney height will become noticeable when you open the loading door of a burning stove, at very low burn rates, and at the end of a burn cycle as the firebox naturally cools regardless of the chosen burn rate.

 

[corona5k1635]

Yes, the lower you run (or the warmer the outside weather is), the less buoyant the air in the flue is, and thus the less the draft sucking new air into the stove is.
You'll have to increase the thermostat setting a bit to get the same BTU output then.

You can always add sections of class A on top (bracing needed at 5 ft ). First indication of not enough draft will likely be smoke roll out when you open the door.

Also note that you'll have to find the thermostat setting that is your (weather dependent) minimum. That's different for each install. And the range in which you go from that minimum sustainable (cat remaining active) burn rate to the max will be far less than the full swing of the knob.

Do you have wood that's already been drying?
Oak will need three years split and stacked off the ground. Maple will be good in two.
Pine or for in one season
Buying wood won't ever be sufficiently dry.
You wont like how the stove behaves when it's forced to consume fuel it doesn't like.

Do read the manual before and during operation.
Close bypass when the cat gauge shows active range, never open the door with the bypass closed.
To reload, open bypass, wait a few minutes, slowly open the door, fill,.close the door,.let the fire start (for truly dry wood that's less than a minute), close th bypass if the gauge still shows active, let the fire rip for a bit (15-30 mins), and I'm 3-4 steps separated by 5-10 mins dial down to your desired heat output.

Thank you very much for the details. Indeed I have been reading the instruction manual. It’s actually a bit overwhelming. But I think I’m getting
it bit by bit

 

[corona5k1635]

If you have the king already then I too would recommend all 8" and the offset in the stove room with double wall. I don't think the 30 degree offsets will be a big deal and expect good performance on 15'.

My princess is only on 12' of stack which was the minimum required back in 2012 when I installed it. I get no smoke smell and run on low 95% of the time. They, BK, have since increased that minimum to 15'. I bring this up to point out that my princess works great on less than the 15' minimum. I think they added a conservative fluff factor going from 12 to 15. Regardless, give it a shot and if needed you can add more. If I were you I would add at least the maximum you can right now without a roof brace. Oh and don't put a bird screen on the chimney cap unless required by law in your location.

Insufficient chimney height will become noticeable when you open the loading door of a burning stove, at very low burn rates, and at the end of a burn cycle as the firebox naturally cools regardless of the chosen burn rate.

Thank you for sharing that… this is very encouraging.!

 

[stoveliker]

I agree with highbeam; if roof access is feasible, it's easy to add class A sections (and bracing if needed) later.
If it works well without, save some $$ and test first, knowing what the signs are of a flue that's too short, so you will recognize it. (and not get frustrated with the stove when it's a flue issue)

Good luck, and show us some pics when installed - and with fire

Note that the first few burns it'll stink because the paint will be curing. Best to do that with windows in the stove room open (and doors to other places in the home closed). A box fan in one window (or two in opposite windows, blowing in and out) will help.

 

[corona5k1635]

If you have the king already then I too would recommend all 8" and the offset in the stove room with double wall. I don't think the 30 degree offsets will be a big deal and expect good performance on 15'.

My princess is only on 12' of stack which was the minimum required back in 2012 when I installed it. I get no smoke smell and run on low 95% of the time. They, BK, have since increased that minimum to 15'. I bring this up to point out that my princess works great on less than the 15' minimum. I think they added a conservative fluff factor going from 12 to 15. Regardless, give it a shot and if needed you can add more. If I were you I would add at least the maximum you can right now without a roof brace. Oh and don't put a bird screen on the chimney cap unless required by law in your location.

Insufficient chimney height will become noticeable when you open the loading door of a burning stove, at very low burn rates, and at the end of a burn cycle as the firebox naturally cools regardless of the chosen burn rate.

No bird screen? I guess it just gets gunked up with the cool crud at the top of the cool pipe? Looks like my installer has listed a cap with a screen for it. Hmmmm now I'm lookin at caps online. Most have screens. Do you mean something like this: https://www.efireplacestore.com/drv-fsflexrc8.html

 

[Highbeam]

Unless required by some local law I would opt for a cap without a bird screen. They plug up even with the much less efficient stoves and are always working against draft.

My duravent class A cap had a birdscreen option. On one chimney the pro installer opted for the screen which was easily removed after it kept clogging up with dry, brown, junk. My second cap was ordered without one.

DuraTech Class A Rain Cap 5" to 8" - 7 in. - Rockford Chimney

The DuraTech Chimney Cap easily attaches to the top of the chimney pipe and is used to prevent weather or animals from entering the Class A chimney pipe.

www.rockfordchimneysupply.com

Golly they've gotten expensive.

 

[bholler]

No bird screen? I guess it just gets gunked up with the cool crud at the top of the cool pipe? Looks like my installer has listed a cap with a screen for it. Hmmmm now I'm lookin at caps online. Most have screens. Do you mean something like this: https://www.efireplacestore.com/drv-fsflexrc8.html
View attachment 337934

I put screens on every chimney or liner i do and rarely have an issue. I do have tons of issues with birds nests if I don't use them though.

 

[DuaeGuttae]

I put screens on every chimney or liner i do and rarely have an issue. I do have tons of issues with birds nests if I don't use them though.

Maybe bird species on the east coast are different from those out west. I would not want a screenless chimney cap either as I would not want birds in my stove in the summer. I've known of many a person to have birds build nests or have them get in the house. I have in the past had some occasional build up on the screen [once where it gunked up pretty fast when we got into a section of wetter wood]. I've never had a problem getting it clean with a sooteater, if necessary. Since @bholler is even closer to you geographically, I'd take his experience into account. I'm currently trying to remember which forum member has posted a picture of a bluebird in his Blaze King King, but the name is eluding me right now.

This is my first year burning a Blaze King, and we did do a midseason cleaning in January when we had a warmer spell. I don't know that we really needed it, but we did it because we had the opportunity and wanted to verify how we were doing. Even with burning low, I don't think that our screen was gunked up at that time. The big difference could be the height of our pipe, though, as it goes through two floors and an attic space before exiting the house and then goes even farther to clear the peak of the roof. We're definitely well above the minimum, and so we have a nice draft even on warmer days. The stove still turns down nice and low, though.

I think you'll enjoy your stove once you get it installed. If there's still enough cool weather left by that time, it would be good to get the initial burns done so that you can get the paint -curing smell taken care of when you can open windows. If your wood needs another summer to season, though, I'd hold off until fall.

Edited to add: @Dieselhead , was it you with the birds?

 

[stoveliker]

@sneefy has had birds in his stove, and @vatmark

 

[Dieselhead]

Maybe bird species on the east coast are different from those out west. I would not want a screenless chimney cap either as I would not want birds in my stove in the summer. I've known of many a person to have birds build nests or have them get in the house. I have in the past had some occasional build up on the screen [once where it gunked up pretty fast when we got into a section of wetter wood]. I've never had a problem getting it clean with a sooteater, if necessary. Since @bholler is even closer to you geographically, I'd take his experience into account. I'm currently trying to remember which forum member has posted a picture of a bluebird in his Blaze King King, but the name is eluding me right now.

This is my first year burning a Blaze King, and we did do a midseason cleaning in January when we had a warmer spell. I don't know that we really needed it, but we did it because we had the opportunity and wanted to verify how we were doing. Even with burning low, I don't think that our screen was gunked up at that time. The big difference could be the height of our pipe, though, as it goes through two floors and an attic space before exiting the house and then goes even farther to clear the peak of the roof. We're definitely well above the minimum, and so we have a nice draft even on warmer days. The stove still turns down nice and low, though.

I think you'll enjoy your stove once you get it installed. If there's still enough cool weather left by that time, it would be good to get the initial burns done so that you can get the paint -curing smell taken care of when you can open windows. If your wood needs another summer to season, though, I'd hold off until fall.

Edited to add: @Dieselhead , was it you with the birds?

Yep you remember that! What a shame. Gotta say though none since them.

 

[EatenByLimestone]

We’ve pulled a lot of squirrels out of screen free caps.

 

[bholler]

We’ve pulled a lot of squirrels out of screen free caps.

Yup and raccoons all types of birds. The raccoons are generally very angry about it. I even had a very confused groundhog once. No idea why or even how it climbed the chimney it was an earth sheltered home so the roof was no issue.

 

[EatenByLimestone]

I haven’t pulled a raccoon out of a class A or lined chimney. Terra Cotta is no match for their skills though!

 

[bholler]

I haven’t pulled a raccoon out of a class A or lined chimney. Terra Cotta is no match for their skills though!

Yeah those are always in fireplaces unusually 12x12 clay