Jotul F3CB, installation and general use tips???

[Intheswamp]

Ok, I figured I'd put an appropriate title on this one. As I mentioned in another post, I've put a deposit down on an F3CB and should be getting it in a week or so.

I had a panic attack yesterday when I realized I hadn't actually measured the space inside my chimney. The F3CB calls for a 6" flue, which in most instances results in a 6.25" OD. Adding to that 1/2" insulation and it comes up around 7.25" OD. I had been figuring I had enough space but....got the folding ruler out this morning and I've got 9-5/8" across the narrow dimension. PHEWWW The cement that squeezed out from between the bricks isn't too bad either so it shouldn't snag the liner very much as it is installed! Thankfully, I'm good there.

Reading the manual it looks like the proper stove pipe to use at the stove is single-wall, correct?

My chimney is an interior one and my flue is going to be roughly 23-24 feet tall with the stove venting from the rear. Looking at it, there will roughly be 16 inches between the stove and the tee with a slight upward angle. With that length of flue should I be on the lookout for over-drafting?

For the F3CB, what is the best length of firewood? Jotul states 18", but is there enough room to easily use that length of wood? Seems I've read where a shorter split works better.

I'm still debating on a liner kit. Currently looking at the Flex King Pro and the Rockford Deluxe Smooth Wall. I see that Rockford has an option for a "standard" flex liner that is $135 than the smooth wall. I'm thinking that the smoother wall might be worth the added premium. Any thoughts shared on these liners are appreciated.

Liner installation...top or bottom? Yelp, I've read several threads. My lintel is only 27" high so I'm thinking installing from the bottom might be a bit ornery...but, shoving a 25" piece of ss pipe down from up top doesn't seem to appealing, either. I've got a painted metal roof on my house...it seems the wire mesh wrapped liner could possibly scratch up the paint. Thoughts?

Durock...I read a while back where it had be de-listed (or whatever) for use in building a hearth board. What can be used in it's place?

Thanks for the help....wood burning is coming closer to becoming a reality!
Ed

 

[begreen]

Your flue height should work fine for draft. Try to stick with 16" wood for the stove. If you can't find the old style cement board (Durock or Wonderboard) at a lumberyard, I'm thinking we don't have a lot of choice but to use Durock NextGen. At least they have confirmed that perlite is the filler. Not sure about Wonderboard NextGen. Maybe others have some thoughts on this. The F3CB needs a well insulated hearth of R=1.1. Did you locate some insulation board to go under the cement board already? Or were you planning on building up 4 layers?

 

[Intheswamp]

Thanks for the reply, BG. Seems my stove odyssey has been a case of ups and downs...but, I'm getting excited again!

Ok, I'll wait and see how the draft is with my flue height. Knowing that the F3CB doesn't have a long burn time I'm hoping to get a good balance between draft and burn time without sacrificing a clean flue....I've got a lot to learn.

16" on wood length...how about split thickness?...just split a variety of thicknesses?

I haven't located any material for the hearth board, yet. I'll be looking for and gathering materials over the next few weeks....it's a tough year-end at the office so it's kind of busy. I'm figuring on sometime in January having the install completed.

I've gotta limit the thickness of the hearth board due to that low 27" lintel so I'll be incorporating a sheet of micor. I've got a lot of sourcing to do it looks like.

I did read up a little on the Durock Nexgen. I don't know how to interpret what I found regarding it's fire/heat handling abilities. The website stated that "The board is non-combustible and can be used in a variety of fire-rated designs. Its low thermaland hygrometric expansion help prevent finish cracking.". It also stated, in a list of features "Fire Rated" and "Fire Class A". What that means is greek to me...????

Ed

 

[begreen]

The F3CB doesn't take many splits to fill it. Try to keep the split size under 6". 3-5" work best.

I'm hoping that USG is getting the NextGen product tested for hearth use. Right now at best we have conflicting information and I notice their website keeps changing.

 

[WOODBUTCHER]

That stove is a nice little heater, my BIL up in Maine has one. His splits are different sizes and under 18".
The best thing I like about that stove is the air control top right, much better than the F600 and the F500 air control.
Your stack setup should draft really good........When I visit family up in Maine, I can get that sucker up to temp real quick.

Good luck!

WoodButcher

 

[begreen]

Interesting, it is convenient to not have to bend over. Still, I like the bigger stove's air control much better. No gloves needed and smoother.

 

[Intheswamp]

Thanks Woodbutcher and BG. Just the little off-the-cuff comments like what was said about the air control and what BG said about using gloves helps...I can imagine not thinking and grabbing that handle with the bare hands! YEOOWWWWW! ...now I know.

Wb, glad to hear the good report about your BIL's stove.

Touching back on the Durock Next Gen, here is another quote from the website: "Like traditional DUROCK® cement board, the next generation of DUROCK cement board is also non-combustible." I was looking at the MSDS sheet and saw that it's title only stated "Durock" and didn't mention "Next Gen" so I posted a note to them inquiring about it and specifically Next Gen's heat/fire handling capabilities. Maybe they'll respond....

Anybody want to comment on the Flex King Pro versus the Rockford Rock Flex Deluxe or the Rockford "standard" liner kits? Still trying to decide on that.

Thanks, again, for the help,

Ed

 

[Intheswamp]

I got a short response from USG, basically a copy of the new MSDS that included the Next Gen. I've attached a copy of it to this message. Looks like there is a "Blend of Proprietary Mineral Based Ingredients" that wasn't noted in the old Durock MSDS.

I think I'll tweak their ears a little more...

Edit: The system wouldn't let me post a pdf file so I just copied and pasted the ingredient list below...kinda jumbled but hopefully you can read it....might be old news, though.

Ed

SECTION 3
COMPOSITION, INFORMATION ON INGREDIENTS
MATERIAL WT% CAS #
Portland Cement <50
Fly Ash <50
Expanded Clay Aggregate <30
Or Expanded Shale
Blend of Proprietary Mineral Based Ingredients <20
Fiber Glass Scrim <5
Crystalline Silica <5
65997-15-1
68131-74-8
68334-37-2
68476-95-9
Proprietary
65997-17-3
14808-60-7
All ingredients of this product are included in the U.S. Environmental Protection Agency’s Toxic Substances Control
Act Chemical Substance Inventory and the Canadian Domestic Substances List (DSL).

 

[fishingpol]

I put in the Rockford standard 316ti kit with insulation. It went in just fine. I did not use the spray adhesive to hold the insulation. I had the wife putting a strip of tape every foot as I wrapped the insulation over the liner. One long tape seam up the length after that. I did the stainless mesh over the insulation. I went and picked up a small roll of s/s wire and wrapped one piece around the mesh every foot after I took in the slack of the mesh. I fashioned a pulling block out of a 2"x4" across the inside of the liner with an eye hook. My liner was 25 feet long and it was interesting dropping it down the flue. I would probably not do a bottom up install, just having to flex the liner and get it up through the damper opening is a chore in itself and then trying to straighten it out as you push up is another thing. With your opening, it sounds like it should drop in nicely with your inner dimension on the narrower sides of the flue. Maybe put down a few old blankets on the roof to prevent scratching. Once you get the end of the liner in the flue, it will be sticking up probably 8' - 10' feet up and then slink over.

I am looking into an F3 maybe in the future. I have a 28 inch opening height to the lintel, a short leg kit may be in order for me to get my front clearance as I would have to recess it a bit, maybe top vent it. I just wish the top vent was in the back more that the center of the stove top. I will look to this post with interest and see how your install goes. I have had the liner for only a few months now, so I have yet to clean it. The stove performance is excellent now with it. It was the best thing to do.

 

[Intheswamp]

I put in the Rockford standard 316ti kit with insulation. It went in just fine. I did not use the spray adhesive to hold the insulation. I had the wife putting a strip of tape every foot as I wrapped the insulation over the liner. One long tape seam up the length after that. I did the stainless mesh over the insulation. I went and picked up a small roll of s/s wire and wrapped one piece around the mesh every foot after I took in the slack of the mesh. I fashioned a pulling block out of a 2"x4" across the inside of the liner with an eye hook. My liner was 25 feet long and it was interesting dropping it down the flue. I would probably not do a bottom up install, just having to flex the liner and get it up through the damper opening is a chore in itself and then trying to straighten it out as you push up is another thing. With your opening, it sounds like it should drop in nicely with your inner dimension on the narrower sides of the flue. Maybe put down a few old blankets on the roof to prevent scratching. Once you get the end of the liner in the flue, it will be sticking up probably 8' - 10' feet up and then slink over.

Good info! Thanks! I have read the instructions and watched some videos but your info defintely helps. Of course, I've got some questions.

Was there a reason that you didn't use the spray adhesive?

When you say you "took in the slack of the mesh" do you mean pulling it tight from the ends or...?

That's one thing I noticed on the Rockford was the absence of the wire. Lowes or Home Depot has it, I guess?

Well, you've convinced me not to do a bottom-up liner install. I had watched the videos and the guys uncoiling the liners seem to be meeting a fair amount of resistance. It seems it would be a chore bending it up through the firebox, especially with my 27" lintel height, and then like you stated trying to straighten it back out as it goes in the chimney would probably be *really* fun. Ok, top down. I had been thinking about using some blankets...or maybe some cardboard zip-tied to the assembly and then snipped off as the liner goes down the chimney. Hmmm, do you have a weight estimate for the assembly?

I am looking into an F3 maybe in the future. I have a 28 inch opening height to the lintel, a short leg kit may be in order for me to get my front clearance as I would have to recess it a bit, maybe top vent it. I just wish the top vent was in the back more that the center of the stove top. I will look to this post with interest and see how your install goes. I have had the liner for only a few months now, so I have yet to clean it. The stove performance is excellent now with it. It was the best thing to do.

The F3CB I think will serve my purposes well. I really searched and struggled to come to this decision. I'm looking for something to compliment our present geothermal system and for an emergency heat backup. I figure the times that the F3 keeps the geo unit from kicking on is just some more $$$ not going to the power company. You have an inch more clearance than I do, I'm going to cutting it close with my install with the short leg kit because I've still got to build a hearth pad.

Here's a link to my original thread where I anguished over choosing the F3CB and some tripwires that I hit... https://www.hearth.com/talk/threads/56653/

I got the call today that the stove has arrived at the shop...now to figure out when to make the 250 one-way drive.<groan>

Best wishes,
Ed

 

[fishingpol]

Funny you should ask about the spray adhesive. I just used a bunch of the stuff on my daughter's Barbie House project to stick down carpet and wallpaper. The stuff can get messy. I've read in other posts that it was a pain. I just felt after wrapping the insulation and taping it every foot or so, it was not necessary. I also felt that if I misjudged the insulation length and had to remove some during the install at the block off plate, I would have to scrape the stuff off. I would rather have a clean liner to look at and eventually paint black where it is visible behind the stove.

I believe the insulation kit came with two screw type bands to secure the insulation at either end of the liner. The mesh cover is oversized to fit over at least an 8 inch liner diameter or more. The extra mesh, I just rolled up like you would roll a paper bag and then put the s/s wire around that and move down liner a foot or so and repeat. It just made it easier to handle with less of a snagging risk. The s/s wire can be had at a hardware store or maybe Home Depot. I paid about $5.00 for 25 feet.

Your idea of taping cardboard to the liner to prevent scratching is an excellent idea, I kick myself for not even thinking of that. Remove it as you go. I found the rain cap and t-connector are of very good quality. The snout of the "t" can be cut with snips. Good luck with the install. I will continue to mull over a purchase of the F3.

Jon

 

[Intheswamp]

Thanks for sharing your thoughts on the glue. That makes good sense to me...the worm-gear clamps ought to hold the mesh/blanket assembly in place, the only purpose I can see in the glue is to hold the blanket in place while the tape is put on. Yelp, the glue is a sticky mess to work with...gotta be careful of whats around when you use it (overspray). Barbie House....Christmas present or on-going project?

Thanks again for your information. I've still gotta get up top and get an exact measurement...I've guesstimated so far by counting courses of bricks...it's time to drop a tape measure down the flue for a more exact measurement. I'm still torn between the Rockford and the Flex King. I like the idea of the smoother inside of the "Pro"/"Smooth" versions. It looks like the Rockford carries a $35-$40 premium over the Flex King Pro. I've sent a query email to both the standard Flex King website, the Flex King eBay store, and to Rockford....so far only the Flex King websites have responded...??

Thanks again for the info,
Ed

 

[fishingpol]

The barbie house was a year long off and on project for my daughter. It is done and she barely plays with it. I can't give you much advice on the Flex King as I have not seen it. There are probably some postings in here somewhere. I've read a bunch in the past, and it didn't appear that one company stood out more than the rest.

 

[Intheswamp]

Well, I went up on the roof today and took a look at the chimney top. I had earlier removed a piece of rigid foam insulation from the firebox that had sealed the chimney off from losing heat and there are three bricks lying side-by-side on top that roughly blocks the opening at the top of the chimney When I removed the bricks bits of dust, spiderweb, etc., starting blowing out of the chimney...it was drawing pretty strongly from just the heat in the house! Anyhow, I was about three foot off from my 25' guesstimation from hearth to chimney top...I measured 21'10" from the bottom of the firebox to the top of the chimney.

My memory must be just about gone. For some reason I had it in my mind that there were bricks bridging the narrow dimension of the chimney opening...I even posted a drawing of what I "remembered" in another thread. Not so, it's wide open. Problem is, though, is that the mason choked down on the opening's size....the flue's narrow dimension down n the chimney is 9-5/8" but the mason closed it in to 9"x5". I knew I was going to have to do some masonry work up there but it looks like there's got to be 2 courses (about 6-1/2") of brick taken off the top to get down to a couple of pieces of flat iron that they are resting on. These iron bars create the 5" dimension that is too narrow and will need to be removed. I'll leave it up to the mason to figure out what to do after that.

Anyhow, I know a little more about what I'm looking at now... Ed

 

[Intheswamp]

The barbie house was a year long off and on project for my daughter. It is done and she barely plays with it. I can't give you much advice on the Flex King as I have not seen it. There are probably some postings in here somewhere. I've read a bunch in the past, and it didn't appear that one company stood out more than the rest.

<chuckle> I hear ya on the vacant Barbie house...if you ever get younguns figured out let me know....mine oldest is 29 now and the youngest 25(?)...both girls, I feel your pain...now I'm being blessed with granddaughters.

What you said about not reading about one company standing out more than another seems about right. I've really yet to hear anybody say anything bad about either of them, mostly just good reports which is unusual because most of the time it seems folks tend to holler out when they have a bad experience rather than a good. Right now the Flex King Pro appears to be cheaper by several dollars (and it comes with the wire<grin>). I'm going to call and talk with them tomorrow.

Take care,
Ed

 

[fishingpol]

Seems just like when you think you have if figured out a wrench falls into the works. I hope your mason can do a good job for you and once this is completed you will have a safe install. It can be a long and frustrating road with dozens of scenarios in your head and on paper,hope you pick the right one.

Jon

 

[Intheswamp]

Seems just like when you think you have if figured out a wrench falls into the works. I hope your mason can do a good job for you and once this is completed you will have a safe install. It can be a long and frustrating road with dozens of scenarios in your head and on paper,hope you pick the right one.

Jon

Yelp, problems will raise their ugly heads at times but it's like a poster my brother had in front of his desk at work years ago..."Obstacles are what you see when you take your eyes off of the goal".

I know the actual installation would probably be very aggravating/frustrating/tedious/etc., but I've re-visited the thought of doing a bottom-up liner install. I think once the liner got to the top that it could be ovalized a bit to come through the 9"x5" chimney opening.

I could bevel off some of the existing cement to allow the liner to round back out some as it comes through the opening. That would mean that roughly 6-7 inches of liner would not be insulated below the top plate connection...I could stuff some insulation material down around it, but part of the metal liner would still rest/press against the last few courses of brick on the two narrow sides. Whether that would act like a giant heatsink and cost condensation or not I don't know...also, I know it's stainless steel but I'd still be wondering about possible corrosion there on down the road a few years.

Probably best thing is to let the mason modify it and be done. Who knew putting a wood stove in could be so $fun$.<groan>

But, I gotta keep smiling.

Ed

 

[fishingpol]

If you did ovalize a bit at the top to get through the narrow spot, you might have problems getting the top cap in if you are going that route. (I hope I didn't drop another wrench in). I believe most liner kits use the top plate with a worm drive clamp to hang the liner down from it. I don't know it is code, but could the mason tear down to the wide portion of the flue, install terra-cotta and brick up around it. My 2 chimneys were re-built from the roof line up as there was no clay flue from the roof up. I guess it was common practice in the 1920's to do that my mason said. Go figure, how much more was 2 or 3 sections of flue tile back then? He left a few inches of terra cotta above my brick and I fastened the terra cotta top plate with nice stainless screws that came with the cap. It worked out really well.