Jotul F 3 CB opinions

[ultimate buzz]

heat shield

Not to hijack the original post, but the idea of putting up heat shields on the exterior walls of the interior of the existing masonary fireplace sounds like an excellent idea.

I have a Jotul fireplace insert,and although there is a block off plate and the stainless steel liner is insulated, i feel that the heat loss to the existing masonary fireplace is quite considerable. The masonary fireplace is on an outside exterior wall.

What do you feel would be a suitable heat shield? A heavy gauge sheet metal with a layer of kaowool against the masonary walls, screwed into the masonary walls or ?
Any input on this would be greatly appreciated-ken

 

[skmag357]

Not sure what a heat shield is but the fireplace did have a ventalater blower system. The inside of the fireplace is at least 1/4" steel with two blowers on each side in the wall. I got the stove and pipe at a great deal and it fits perfectly in the small space that I have. That is why I bought it. If the temps outside get up to 40, I can heat the whole house up to 80 degrees. Lower than that and it stays around 65 which is fine by me. I never really overfire the stove either. When I say that I reload the stove every 30 mins or so, I am adding wood to keep the fire ripping. My lower seals do look like they need to be replaced and I plan on ordering the gaskets soon. I also cut up my logs smaller to fit them in the stove so that may be the issue as well.

 

[Intheswamp]

Quick note here...

Heat shields can be made of thin metal...no need for heavy stuff. The trick is using "stand-offs" to hold the metal about an inch away from the surface being shielded. Stove shops sell stand-off kits with ceramic insulators and appropriate size screws.

Shields are usually used to protect combustible surfaces when there is a problem meeting clearance specifications. ...cabinets, mantels, trim work, etc.,.

26 gauge roofing metal should work fine and be fairly durable. Standoffs can be made from metal tubing...stainless steel would be best to reduce chances of corrosion at the area where the roofing meets the standoffs. Dissimilar metals can cause "galvanic" corrosion. Those ceramic standoffs would work very well.

Unpainted metal roofing naturally would be best...paint it with some bbq high-temp paint. Or...your metal roofing company might actually have some metal already painted with a high temp paint..???

Leave a 1" gap at the bottom and top so that air can circulate behind the metal, bringing cool air off the floor, up, and out the gap at the top to flow out of the fireplace.

I'm not sure how existing lined fireplaces are constructed...if the metal liners are in contact with the brick/mortar then they are probably conducting the heat to the outside, also.

Best wishes,
Ed

 

[Intheswamp]

ultimate buzz, I've often wondered about insert surrounds. I've read where several people have removed the surround and been surprised by the increase in heat output they get. Having said that, I'm curious about whether ventilation holes/slots would help in letting some of the heat behind the inserts enter the room. Some of that sheet metal from the roofing company might could be mocked up as a surround with some holes/slots punched in it to give it a try. Just thinking outside the box.<grin>

Ed

 

[Intheswamp]

Not sure what a heat shield is but the fireplace did have a ventalater blower system. The inside of the fireplace is at least 1/4" steel with two blowers on each side in the wall. I got the stove and pipe at a great deal and it fits perfectly in the small space that I have. That is why I bought it. If the temps outside get up to 40, I can heat the whole house up to 80 degrees. Lower than that and it stays around 65 which is fine by me. I never really overfire the stove either. When I say that I reload the stove every 30 mins or so, I am adding wood to keep the fire ripping. My lower seals do look like they need to be replaced and I plan on ordering the gaskets soon. I also cut up my logs smaller to fit them in the stove so that may be the issue as well.

I think if you could get the F3CB out further into the room...more on the hearth than recessed into the fireplace that it would give you more heat. I'd go ahead and order that gasket as that will help get the stove back to "spec"...and might just improve your burn time. It seems the stove is putting out plenty of heat...you just need longer burn times. What kind of wood are you using? Is it well seasoned...from what I understand the F3CB is rather picky about burning well seasoned wood. Are you getting an hour or so of secondary burn?

Ed

 

[sunfish]

The 3CB is a fine stove, but it's small. It'd work very good for an open floor
plan of around 1200 sq ft. But not a larger multi room and or two story house.
Too big a stove is also not good, because you can't run the stove hot and
efficient. I know, I've been at both ends of the spectrum.

Very dry wood, cut close to max length is also needed, but this is the case for
most of these modern air tight stoves.

And like said, stuffing a free standing wood stove into a fire place is not going to put out the heat that it would sitting out in the room.

 

[colin.p]

another "me-too" post. I am on my 5th winter with the F3CB and must say it works very well. All the short comings of the stove are true for me as well, but the benefits far out way those. I heat a 1904 eastern Ontario, 2 story 24X24 foot farm house, that there is no problem with not getting enough fresh air. However, my oil furnace will come on over night, or if the temps drop into minus 15's or so, but my 3 foot thick field stone foundation isn't the most air tight and I would prefer my furnace kicking on and not my pipes freezing. The floors can get quite cold with no heat in the dirt floor basement.
I get 2-4 hours between loads and if I fill the stove (usually just one large log), I get upwards of 6 hours or so. The stove will take an 18 inch stick, but 16 is optimal.
I like the fact that if I take the front log retainer out, I can get a fatter stick in, that's why I have a pair of channel lock pliers handy.
If I were going to do it again, I would have liked to get the 400 Castine, but I will stay with what I got.
Ash is my favourite and seems (at least to me) to be the most reliable burn. I am now getting into my 2 year old oak and ironwood, now that throws out some heat. Maybe get some apple for next year...

 

[sdt7618]

Lesson I learned the hard way a few years ago, damp( i.e un-seasoned) burns like Carp!.

to my mind stack the wood you have and leave it till next year. Find a good supplier to finish this season and get wood bought for next season now if you don't plan on cutting soon.

Stay safe what ever you do.

 

[myzamboni]

Quick note here...

Heat shields can be made of thin metal...no need for heavy stuff. The trick is using "stand-offs" to hold the metal about an inch away from the surface being shielded. Stove shops sell stand-off kits with ceramic insulators and appropriate size screws.

Shields are usually used to protect combustible surfaces when there is a problem meeting clearance specifications. ...cabinets, mantels, trim work, etc.,.

26 gauge roofing metal should work fine and be fairly durable. Standoffs can be made from metal tubing...stainless steel would be best to reduce chances of corrosion at the area where the roofing meets the standoffs. Dissimilar metals can cause "galvanic" corrosion. Those ceramic standoffs would work very well.

Unpainted metal roofing naturally would be best...paint it with some bbq high-temp paint. Or...your metal roofing company might actually have some metal already painted with a high temp paint..???

Leave a 1" gap at the bottom and top so that air can circulate behind the metal, bringing cool air off the floor, up, and out the gap at the top to flow out of the fireplace.

I'm not sure how existing lined fireplaces are constructed...if the metal liners are in contact with the brick/mortar then they are probably conducting the heat to the outside, also.

Best wishes,
Ed

Exactly what I did. Stainless using aluminum square stock as stand-offs.

 

[Jtracy]

Colin - Your home is 24 x 24 2 floor...and is the floor plan open? My home is about the same (just a tad larger) but with 4 rooms on each floor, hence walls that separate each room (approx. 4 rooms at 13 x 13). We were considering the same with taking off the log barrier, and now that we know you do it, we may do the same. Again, our problem is that the room with the stove in it (13 x 13) has reached a MAX heat of 78 degrees, while the adjoining rooms are between 67-69 degrees! Our burn time with 1 or 2 logs (after lots of embers is approx. 30-40 minutes....we are seriously thinking about calling the dealer this weekend to change the stove out for the 400 Castine...but i need to blog to see how it may work in our home - 2 floors approx. 1,000 sq. ft. on each floor.

If anyone has thoughts, please share!

 

[Intheswamp]

I don't know it for a fact, but I've read other user's comments that the Castine may be more prone to backpuffing if conditions are favorable...I would also be a bit concerned that the Castine would turn your 13'x13' room into a heatstroke room being as it's rated for an area well over 10x that size. As for the backpuffing I would be sure that I had more than a minimal draft before going that route.

I'm curious...once you get the F3CB burning and get the big pieces of wood charred and burning good do you start gradually cutting the primary air back? ...at some point in reducing the primary air secondary combustion should happen and the "tubes" should light up and give a good light show with good heat....this should be an efficient burn happening. Getting a good burn going while reducing the primary air will keep a lot of your heat from rocketing out of your chimney.

It does seem that the F3CB might be too small for your climate and structure. But, putting in a larger stove seems like it would make the room that it is in too hot. Kind of "dinged if you do, danged if you don't" situation. Is the house well insulated and no major air leaks? It seems the F3CB should be heating your square footage better than it is (it's rated for more square footage than you have), even with the fact that it doesn't have an open floor plan. ????

Ed

Colin - Your home is 24 x 24 2 floor...and is the floor plan open? My home is about the same (just a tad larger) but with 4 rooms on each floor, hence walls that separate each room (approx. 4 rooms at 13 x 13). We were considering the same with taking off the log barrier, and now that we know you do it, we may do the same. Again, our problem is that the room with the stove in it (13 x 13) has reached a MAX heat of 78 degrees, while the adjoining rooms are between 67-69 degrees! Our burn time with 1 or 2 logs (after lots of embers is approx. 30-40 minutes....we are seriously thinking about calling the dealer this weekend to change the stove out for the 400 Castine...but i need to blog to see how it may work in our home - 2 floors approx. 1,000 sq. ft. on each floor.

If anyone has thoughts, please share!

 

[colin.p]

Colin - Your home is 24 x 24 2 floor...and is the floor plan open? My home is about the same (just a tad larger) but with 4 rooms on each floor, hence walls that separate each room (approx. 4 rooms at 13 x 13). We were considering the same with taking off the log barrier, and now that we know you do it, we may do the same. Again, our problem is that the room with the stove in it (13 x 13) has reached a MAX heat of 78 degrees, while the adjoining rooms are between 67-69 degrees! Our burn time with 1 or 2 logs (after lots of embers is approx. 30-40 minutes....we are seriously thinking about calling the dealer this weekend to change the stove out for the 400 Castine...but i need to blog to see how it may work in our home - 2 floors approx. 1,000 sq. ft. on each floor.

If anyone has thoughts, please share!

Yes my 1st floor is fairly open. The kitchen, living room and dining room are all open, with the stove in the north west corner of the dining room (which we actually never used as a dining room).
As I said, the house is not air tight. As a matter of fact, when they built this house, they didn't know how to spell "insulation", let alone use it. Over the years when windows were replaced, some was put around the window frames, but between the outer walls there is just brick, and not done very well at that.
I have also heard about problems with the Castine, it uses a different draft control, than the F3. So I may actually have the better stove anyway. (edit: on another forum, a lady who has burnt wood for decades, said that the castine was hard to control, as she has a very strong draft)

 

[sunfish]

I don't know it for a fact, but I've read other user's comments that the Castine may be more prone to backpuffing if conditions are favorable...I would also be a bit concerned that the Castine would turn your 13'x13' room into a heatstroke room being as it's rated for an area well over 10x that size. As for the backpuffing I would be sure that I had more than a minimal draft before going that route.

I'm curious...once you get the F3CB burning and get the big pieces of wood charred and burning good do you start gradually cutting the primary air back? ...at some point in reducing the primary air secondary combustion should happen and the "tubes" should light up and give a good light show with good heat....this should be an efficient burn happening. Getting a good burn going while reducing the primary air will keep a lot of your heat from rocketing out of your chimney.

It does seem that the F3CB might be too small for your climate and structure. But, putting in a larger stove seems like it would make the room that it is in too hot. Kind of "dinged if you do, danged if you don't" situation. Is the house well insulated and no major air leaks? It seems the F3CB should be heating your square footage better than it is (it's rated for more square footage than you have), even with the fact that it doesn't have an open floor plan. ????

Ed

Good post Ed.

Janet, there is no perfect stove, each one as pluses and minuses. I would not want a larger stove in a 170 sq ft room. Like said, would cook ya out. But the #3 is not large enough for 2000 sq ft. Are you sure you have 2000 sq ft?

I would be looking into adding more insulation, better windows and possible taking out some interior walls. Also find a way to move some air around.

More insulation and better windows made a HUGE difference in our home.

 

[Jtracy]

Ed - We have been wondering about the secondary combustion tubes. To be honest, we see minimal usage of them...we see them throw back heat when we put a NEW piece of wood in and the new log lights up. After a log has burned or has little burn, or if there are only embers we do not see them ignite at all. If you have any suggestions on how or why, that would be appreciated, as we had been told they would recirculate the air...hence, produce more heat or keep it heated longer.

As for our home, it is from 1840 so we are not about to break down walls (as it would take out the character) ...and believe it or not, the windows are not too bad!!!....we do plug up any leaks in windows, by the door, etc...but, we certainly are NOT as air tight as newer homes.

I am not sure what backpuffing is (when mentioned for the 400Castine) ?....

Thoughts?

 

[sunfish]

I am not sure what backpuffing is (when mentioned for the 400Castine) ?....

Backpuffing, is when the stove puffs smoke into the room, usually from choking it down too much (closing off the air supply). Or poor draft, don't think draft will be a problem for you.

 

[YotulFrank]

New Stove

Hi,

I just purchased a Yotul F3, and was wondering about the break in instructions. It said to have 1 fire at 200, 300 and 400. It doesn't say the temperature scale C or F. It just has the little circle at the end of the number. That said, once I complete the breakin, what is the operating temperature of the stove at it max output.

Thanks

 

[Axe Man]

I'm pretty sure those temp readings are in F degrees as 400 C is 750 degrees F.

 

[colin.p]

I wouldn't worry too too much on the break in. Just follow it as close as possible, but this little stove is darn near bullet proof. When I got mine, the stove installer wasn't familiar with break in fires and had kind of a glazed look on his face when I told him about it.
So, he started a small fire to check for draft and leaks, I suppose. I then let it die down to around 200 degrees and the fire was pretty well out, then started another one. An hour later, I got impatient waiting for the fire to get going, so I left to go to town (draft control at half way). An hour or so later, I arrived home to the dog barking, both &^%$#@!!! smoke detectors going and the stove was at 500 degrees. That was the extent of my break in and started using it full time after that. No harm done, and after 5 years, still a good little stove.

 

[v8titan]

Ed - We have been wondering about the secondary combustion tubes. To be honest, we see minimal usage of them...we see them throw back heat when we put a NEW piece of wood in and the new log lights up. After a log has burned or has little burn, or if there are only embers we do not see them ignite at all. If you have any suggestions on how or why, that would be appreciated, as we had been told they would recirculate the air...hence, produce more heat or keep it heated longer.

As for our home, it is from 1840 so we are not about to break down walls (as it would take out the character) ...and believe it or not, the windows are not too bad!!!....we do plug up any leaks in windows, by the door, etc...but, we certainly are NOT as air tight as newer homes.

I am not sure what backpuffing is (when mentioned for the 400Castine) ?....

Thoughts?

The secondary burn tubes are there to add combustion air to the firebox to aid in full combustion of the fuel. When your fire is down to coals there will be no flames produced up in that area of the stove. When you add a new piece of wood, and the fire box is real hot, small flames will appear to be coming out of the tubes. This is not actually the case. What the tubes are doing is adding fresh air to the top of the combustion chamber and igniting the hot gasses that might otherwise just exit the stove as smoke and unburned fuel.

I believe this is an EPA requirement for non-catalytic stoves now. Others have said that it does improve efficiency. In the case of my Jotul f5, when I have strong secondary burn occurring, the stove is really cranking out the btu's. When I am burning a low fire on a milder day, there is rarely and secondary burn visible.

 

[YotulFrank]

F3

Thanks for the replies. I will have my first normal fire tonight. I'm looking forward to it. The paint smell is still around, hopfully this with subside soon. So 400 - 600 F is a good ranage to run the f3. I have the ash pan, has anyone operated the stove with a cast plate installed, or better said without that ash pan option.

Thanks