Advice: grate for insert

[cityevader]

I have a Jotul 450 insert that has a hard time fully burning.

I attribute this to the poorly desined intake which enteres at the front of the insert, and which has to travel through the ash and coals piled against it. Meanwhile, the secondary burn tubes are sucking freely.

A new fire burns wonderfully from the primary intake, but a couple hours thereafter gets suffocated by ash/coals...meaning the coals no longer "glow from below" and only glow on the surface if new wood added (I assume because the primary air can't get throught the ash and charcoal all the way to the back of the stove where the secondary starts).....so more and more wood gets added so that there is a 5 inch layer of charcoal that would burn fabulous if only there was enough air from below.

Since the primary intake is at the lowest point and easily restricted, I'm thinking about a grate system, but the extremely tiny firebox protests. If a three inch depth grate was put in, only pieces 2-inch in the rear and maybe 7 inches in front could be placed.

Any ideas?

 

[boostnut]

My opinion is your fuel is likely the problem. I think this is the 4th year I've been using my C450 and have learned a lot about running it correctly in the last 2 years (made a few mistakes my first 2 years with it). I have had an opportunity to burn a wide variety of hardwoods and can tell you that this stove will "coal up" with certain species. I'm seeing the same problem you described currently, the hard maple I'm burning is to blame. My solution is to simply stir the ash/coal mix about 10 minutes before reloading, usually this needs to be done twice. Get the coals to the top and open the intake air up 100%, you'll be suprised at how much heat is still trapped in there. That 4 or 5 inch thick coal bed will burn down to an inch or so and you'll have plenty of room to re-load for another 8+ hour burn.

BTW, what kind of wood are you burning and when was it split and stacked? Also, what kind of chimney are you using?

 

[cityevader]

I'm burning white oak as well as madrone, both split and stacked 2 years ago. As dry and lightweight as possible. The madrone leaves far less ash...but still the intake ends up blocked....which leads to more coals whick further block it.

 

[cityevader]

The secondary is plumbed internally to the upper tubes unfortunately. I pull the coals forward(front load door) as the rear bottom area burns the poorest. I use the shovel upside down to push the ash to the back and float the coals to the top, then rake those forward towards the glass.

I just wish for 2-3inches of airspace below for the ash to fall through and provide max air to the coals/logs. The draw back being 25%reduction in firebox capacity.

 

[ultimate buzz]

jotul 450 insert

Boostnut and Cityevader, While you are discussing the 450 insert, I would like to ask you a couple of questions,or at least get your opinions.I recently had a 450 installed with the cast tamarack faceplate.It is installed in a massive exterior masonary fireplace, with about 20 feet of 6 inch stainless chimney liner,professionally installed by a jotul rep. When they did the install,I asked them if it was a good idea to insulate the pipe going up through the 10" x 15" ceramic flue, and they said no, they did not feel it was necessary. Also when damper was removed from the masonary fireplace,they put in sheet metal block off plates,but left them "float" to be able to slide the insert in.The block off plates are not sealed with any kind of silicone or masonary cement,and there is not any kind of heat resistant insulation (kaowool etc.)to seal up gaps around the 6 inch exhaust.The top of the chimney/flue has a one piece stainless cover with the pipe protected with a collar and cap . Would you consider this a proper install? Any suggestions? Thanks, Ken

 

[boostnut]

I can't tell you if that is a proper install, local code determines that.

I can tell you that I ran mine just as you describe for the first 3 years although my chimney is only 10 or 12 feet tall. I installed it myself, made a steel block off plate that, to this day, is not sealed. It just sits on the old damper frame. This fall I took the time to insulate the top 3 feet of my chimney. I purchased some mineral wool insulation made for insulating 6" pipe and slid it around my liner. I have to say that it has had a positive effect on the stoves performance. This may be due to my shorter than suggested chimney though, not sure. If you're burning TRUELY dry wood and still are questioning the stoves performance than some insulation may be worth a try. Its cheap and relatively easy to install. BTW, is your chimney interior or exterior?

 

[ultimate buzz]

yotul 450 insert

Boostnut, Sorry, I thought I had mentioned it was outside on an exterior wall. The wall of fieldstone is a full eight feet tall and about twelve to fourteen feet long,with the fireplace opening a little off center. There is a thermal break,with 2 by 4 walls on the outside,except the six feet where the actual masonary chimney and flue run on the outside. I won't have access to a digital camera until at least sunday, otherwise I would give you an exterior and interior shot. Thanks again for the reply,Ken

 

[cityevader]

My Jotul was a gift from my folks. I wasn't home when the installer ran a 4ft flexpipe into the masonry chimney flue and left it at that. 15ft of bare brick above that! I had to buy the double wall and install it myself. Very dificult, now I knowwhy he had given up. Even more dificult was running a flex pipe for outside air. Many many hours over a weekend to get it to work, so I will never remove it again!!

I think i'll try to shop vac the primary inlet at the front and hope it'll help.

 

[boostnut]

did you ever run it without the outside air kit? is there a noticable difference?

 

[cityevader]

The first, maybe three weeks without outside air were ridiculous, forceful wind from windows and doors and electrical outlets as they fed air into the stove. Now the inside wind is gone.

I tried vacuuming out the primary inlet, negligible effect...although perhaps a little better, I'm not sure if it's real or I'm expecting a change and therefore see one...but I imagine there should be a near-blowtorch effect from the primary with wide open throttle air....but there is only a lazy yellow flame, without the white-hot coals I should expect. I'm gonna try to poke out the inlet from the exterior end to ensure no spiderwebs...and perhaps borrow a portable air tank and blow it bacwards into the primary and out the main inlet. I peeked into the chimny pipe outlet...approx 3 feet above the chimney, and with the screen in place, can only see about 4 inches down the pipe and creosote appears to be about 1/4 to 3/8 inch thick at the very top...haven't cleaned the pipe yet in the 2 years it's been in use.

 

[boostnut]

If you're not getting the "torch effect" with the air wide open than I'd say something is wrong. Start by doing a simple inspection when the stove is cold.

Pull the fan assembly and grab a flashlight. With the fans removed you can look under the doors to the back of the stove. This is where the primary and secondary air enters the unit. The design of the top baffle allows creosote to plug the secondary air intake (since it slopes toward the rear of the stove). Make sure you dont have any creosote in this area far behind the fans. I had a small amount which came out easily. Next you should inspect your primary air control. If you take the 2 bolts out from the inside of the stove pay close attention to how the unit is assembled. Make sure all of these air passages are clean AND verify that when your control lever is all the way to the right the openings are wide open.

With 19' of chimney that thing should draft like crazy. Sounds like somethings wrong. Good luck

 

[cityevader]

Before I disrupt the cover over the primary, is there a special gasket for it should get ahead of time? Or gasket cement alone will work?

I'll peek inside it next. Then let her cool down and clean chimney pipe...except we just had a cold snap here in the Bay Area. Snowed at my place here in the Santa Cruz mountains at 840 ft altitude...not the time to be dinking around with stove.

Maybe I'll just notch out a bit of door gasket at the bottom for temporary "fix".

 

[boostnut]

I was able to salvage and re-use the gasket without any problems.
Personally i think your "temporary fix" is a bad idea. Do whatever you want, its your stove.

 

[Edmccabe]

When I installed my Jotul 550 it became clear that the piece of galvanized metal supplied to block off the chimney wouldn't last or do the job. I removed the fireplace's 48" X 10" cast iron damper and cut a hole in it with the same oval profile shaped as in the Mickey Mouse block off plate and mounted it solidly back into the top of the fireplace and bolted it to its seat with the flexpipe already mounted in it - from the top down.

I found it fairly easy to move the SS flexpipe through the hole into contact with the outlet at the top of the unit - as I had squashed the lower 18" of it to fit through the oval hole and allow movement. I sealed the flexpipe to the former damper with high temp sealer after everything was in place.

The unit works very well heating my home because the air inlet for my regular hot air heating system is in the ceiling close to the chimney above the fireplace.

I find the need to remove ash about every 10 days and usually operate the unit with the door cracked open slightly for a few minutes after adding wood.

Ed

 

[husky455rancher]

nice setup ed looks really good. i woulda moved the pink baslet before i took the pic though. or at least put it near the gun to toughen it up lol.

 

[cityevader]

I’ve always been disappointed with this insert...but a long story would be inolved.....

I seem to remember one-year-old Madronne in my old stove (that I now miss dearly..siiiggghhhhh) burning to nothing. Now I have two-year-old Madronne fire dying out with charcoal chunks left.

Every instinct screams primary resriction. Tonight I poked around with a hanger at the outside air inlet while burning, no airflow change....but it HAS to be inlet problem, since cracking open front door makes some good organ notes as the chimney resonates from a sudden full throttle fire.

Process of elimination brings me back to a restriction in the inlet between the outer pipe and the firebox. Hopefully this weekend will be warm enough to both open/inspect the firebox primary inlet as well as clean the chimney pipe.

BTW, previously i had an old semi-freestanding stove halfway into the masonry fireplace as I bought the house this way back in “02. That thing kicked out heat like crazy, but when I had a chimney sweeper come by he hept muttering OMG...OMG...OMG...over and over. Discovered the stove “vented” with no piping whatsoever, into the fireplace and up a bare brick chimney with huge layer of creosote ready to go up in flames, and man, I truly wish the house DID go up in flames....( but that is a longer story) I simply wanted to “re-pipe” chimney with double wall and keep the stove, but my folks decided to “help” and bought me the Jotul insert and had it installed.

The installers did the same thing, exhausting directly into the brick chimney with no piping except a 4 foot flex past the flue door. So I had to pony up $1000 and install the piping myself. Forever disappointed with the heat output of my "free" insert, that sucks compared the prior stove with more than double firebox size and heat output....So my “gift” ended up costing me a grand and I get less heat out of it.....siiiggghhh

 

[cityevader]

Finally warmed up a little bit, so got home from work tonight, scooped out 5 inches of unburnt charcoal. Tried to remove the front bump of a cover. Only one screw came out. The other siezed and rounded. Scraped out the gasket with a thin hook, which allowed enough free play to spin the cover out of the way, and sure enough, inlet filled with ash. What a ridiculous design. Nothing at all to prevent ash entry. No angled-down-overhang or anything. And if it needs constant maintanence, there should be a different fastening system, or at least some anti-sieze on the bolts.

Cover back on with gasket cement spooged into gap and anti-sieze on the bolt. Fired it back up, intake lever at approx 15-20% position and went out to eat, and there's ash now instead of charcoal! Hoped it would be warmer now, but nope, still same old weak output... and four 4 inch logs nearly burnt out...But at least now I can keep adding fresh wood to keep it blazing. I have a feeling I'll be back to relighting morning fires again, but better to have a little bit of ash and relight, than a bunch of charcoal and coals taking up so much volume.

Overall, I'm still an unsatisfied Jotul 450 owner. The upper secodary "plate" is already falling apart after two years. The first week I tried to remove the front face of the firebox, (can't remember why now) and the first (of four) bolts snapped upon removal attempt...decided not to continue with that. Weak heat output and very short burn time even with intake down almost closed. Terrible rattling of the fan unit no matter how I shim and shift and reposition fan/ashlip. And now prone to plugging....man I sure do miss the powerhouse of a stove that was removed for this thing.

 

[boostnut]

"The upper secodary "plate" is already falling apart after two years" Hey city, i'm curious to know what you mean by this plate falling apart, could you explain further? Thanks!

 

[cityevader]

Where the plate ends at the top where the gasses wrap around and head back to the flue...it's cracked about 3.8" back across the top, and about 5 inches of it has already broke off altogether. It's too high up to really get knocked around by wood.

 

[cityevader]

I spent all day yesterday doing nothing for a change. Yeah!! Spent a lot of time in front of the stove and monitoring the new thermometer stuffed on top center.

I discovered I used to turn the fan on too soon. It appeared it was at full burn, but in actuality was under 300*F and turning on the fan drops temp by 50* regardless of temp. Combine that with the previous problem of lack of primary so charcoal built up so fast that when a new log was thrown in before temp got a chance to rise, it dropped due to log absorbing heat before burning. Vicious circle which keep temp at about 300*.

Now with primary air functioning, and waiting longer before turning on the fan, say 500*, allows higher temps to be maintained and new logs added don’t drastcally lower temps as they used too, and with lowered “coal” bed of unburned charcoal, new logs burn much better, and maintains over 500* at half throttle.

Temp in fire room is noticeably better, but the adjacent room I’m trying to also heat is still nearly 20* colder. That room is 2 feet lower, and there’s a 12” fan on ceiling of doorway and a 20” box fan on the steps to push/pull cold/warm air between rooms....so i’m thinking the 450 puts out enough infrared to make the living room feel warm, without heating the air enough to warm the other room by convection...prior stove warmed both, but it was a sort of freestanding type venting into fireplace vs flush mount 450.

Next step is definitely to try the rockwool around damper to keep convective losses down.