Jotul Oslo Startup and Performance Questions

[senorFrog]

New stove (jotul oslo) has been in for a few weeks now. Been using it regularly (nights and some cold mornings) here in MASS. I have a few questions...

The stove doesn't start very easily. I noticed in other threads that some Jotul owners (castine and oslo) have similiar issues. They crack the door a bit to encourage draft. Sometimes, when opening the side door to add more kindling during startup, I notice the fire starts to burn great. However, with it closed, I have wimpy flame and smoke filled box. I've been able to mitigate this somewhat by using the top-down burn method. That keeps most of the smoke out. However, to establish a good bed of coals and hot fire takes almost two hours. Is it okay to crack the side door for a bit to help this out? Stove burns okay once I get some good hot coals. FYI - I mean the side door not the ashpan which manual says never to crack.

Ironically, once the stove gets going w/a nice bed of coals (and it gets going real nice w/spectacular secondary burn, ghost flames, etc) I can't seem to damper it down real well w/out killing it. I've been going through wood like mad. Haven't gotten anywhere near the nine hour burn times. Stove is always warm with a few coals in the morning. To keep a good burn going I have to leave damper at least half open. Should I always have a good burn with secondary in full force? What's the norm for a burn cycle? How may hours startup, how many secondary, how many glowing hot coals?

I have all six inch double wall connector going into 8x8 clay lined masonry chimney. Two 90 degeree offsets. Fours foot horizontal run pitched per code.

I believe my problem is draft. I'm uncertain how to fix, if at all. Maybe I should wait and see how it performs in the colder weather. My installer want to add a exhausto fan, which I'm dead set against. Considering rebuiling concrete block masonry chimney w/brick and air space between clay liner. Current one has no air space and was done by prev owner. I did add some height to it already. I'd be uncomfortable going much higher. Also, considering tearing out masonry chimney and replacing with class a insulated chimney pipe.

What do guys think? Can anyone tell me what the real world burn times and behavior are for an olso? If I knew what was the norm, then I could ascertain how far I'm out of it. Maybe the easy fix is just to crack door when starting and live with the shorter burn times.

Thanks for reading!

 

[webbie]

Does sound like draft problems....

Do all the usual - make certain furnace cement seals all pipe joints and into the chimney - can you eliminate any 90's and use 45's instead? A sloping pipe will draft better.

Is there an ash cleanout or area of the chimney located below where the stove enters?

Instead of rebuilding chimney, a 6" liner dropped down might provide a better and more stable draft. If you need to extend it beyond the top of the chimney, then I have some of those extendaflue castings that you can use to keep it warm up there.

 

[senorFrog]

Yes, there is an ash cleanout at the bottom of the flue, about 7 feet below where the thimble enters the flue.

Thanks, I was thinking about the extend-a-flue. I think I may need to go much higher though. Considering rebuilding because I think it will probably need it in several years anyways. Also, because it's made out of those ugly concrete cinder blocks.

 

[ChrisN]

Well, when I start my fire I usually place the ash-door handle on the latch, as opposed to dogged tight, then keep the damper all the way open. The side door is shut tight. After maybe 15 minutes I dog the ash-door and just burn with the open damper. I also find it takes a while to build a robust bed of coals, not two hours, maybe an hour. Once up and burning I generally keep the damper at the mid-point, unless it's cold outside and then I open it up as necessary. When I bank the fire before going to bed I let it burn with the damper wide open for 10 or 15 minutes, then close the damper all the way. I usually go to bed around 10pm and get up at 6. the stove will have a healthy bed of coals then to reload onto. I refill the stove and undog the ash-door as needed to get a good box-o-flames built up, and then close everything up and go to work. When the boys get home from school at around 3:30 they reload it and the process continues. I guess I feel comfortable saying the stove will have a healthy bed of coals 8 to nine hours after loading it up. My chimney is all interior, a straight up shot about 30 feet, double walled stove pipe.

 

[senorFrog]

Chris, is your secondary always working through all phases of burn cycle?

 

[elkimmeg]

My second Intrepid II is installed to chimney block exterior chimney with one 90 elbow in the run Chris has detaitled a good routine
it is now cold enough a decent draft should be established. Not all stoves are installed in ideal venting situations. Did you use the super cedar starters?

Ok a little less than ideal , lets work on the current situation/setup supply a picture so we can see the connector pipe route.

It might be as simple as building a proper fire which takes time ultimately 24/7 works best. Stops and starts are least effecient way to heat
It is ok to crack the door to get things going. You have to build the fire with progressive larger splits till the bed of coals are established.
you will use more kindling than others, but once you can get it to 24/7 this is normal. You may find for complete dampering you have to bring that stove up to 650.
You may also heve to expermint with the primary air supply position

 

[senorFrog]

I'll get some pics elk, including the diff burn pics.

Everything to the masonry chimney was swapped out including the thimble. I haven't gotten the stove above 500 yet. In fact, on the warmer days we've had recently it was hard to get above 400.

 

[ChrisN]

Frog, when I have the damper anywhere between 1/3 to full open I generally have a secondary burn going. When I have it damped down, like at bedtime or when the house is empty during the day there isn't a secondary burn.

Chris

 

[ChrisN]

Frog, I keep my magentic thermomter on the back left corner on the top of the stove. When burning with the damper at the mid-point the temp is generally between 450 and 600. If I open the damper it easily goes up to 750 I don't like to burn it much hotter than that. Plus when I undog the ash-door handle it quickly turns into a blast furnace.

Chris

 

[senorFrog]

Geez, generally I haven't been able to get mine past 400. I had it up to 500 once (last night when it was really cold here, just starting to get cold here in MASS). I damped down to half when it hit that mark. Temp dropped back down.

Anyone think an outside air kit would help?

Chris, I tried your method of damping al the way down last night after a good fire was going. The fire died down then I had red embers. Also, I got some sporadic secondary burn. It went like two seconds without, then puff a one second burst of secondary, two seconds with out...puff one seconds of secondary again. Did this for a good while. Eventually I fell asleep watching it. Had a lot of "haze" on glass this AM.

Elk, Working on photos. Also, yes I'm using super cedars plus kindling to start.

 

[senorFrog]

Some pics...

 

[senorFrog]

Some more pics...

Re the chimney, the lighter colored blocks are the ones I recently added.

 

[senorFrog]

Cool hawk from this morning...

 

[begreen]

Nice hawk, hard to tell it's size but I'm guessing it's a Cooper's?

Refresh my memory. Does the furnace have a separate flue or is it tapped into the same block chimney?

The stove should be operating in the 450-650 degree range. Are you getting only 400 degrees with the damper wide open? Try getting a good hot fire going, then damper down to 3/4" and see what she does.

PS: Best to get a blank, gasketed cover or an outdoor light fixture on the open electrical box behind the chimney. That can be a source of undesirable water infiltration.

 

[senorFrog]

Nice hawk, hard to tell it's size but I'm guessing it's a Cooper's?

Refresh my memory. Does the furnace have a separate flue or is it tapped into the same block chimney?

The stove should be operating in the 450-650 degree range. Are you getting only 400 degrees with the damper wide open? Try getting a good hot fire going, then damper down to 3/4" and see what she does.

PS: Best to get a blank, gasketed cover or an outdoor light fixture on the open electrical box behind the chimney. That can be a source of undesirable water infiltration.

Be green, re hawk I don't know much about em, just thought it was cool. It looked so large in the tree at first I thought it was a stuck cat.

Re elec box, will do, I inherited that.

This is a dedicated chimney.

 

[begreen]

That sounds about right. A mature coopers hawk is about 16" tall. We also have the similar but smaller, sharp-shinned hawk which is about 11" tall.

How does the sentry solo vent? or is it an electric furnace? Does it ever run at the same time as the woodstove?

Does the Jotul work better if you open a window in the room?

 

[senorFrog]

How does the sentry solo vent? or is it an electric furnace? Does it ever run at the same time as the woodstove?

Does the Jotul work better if you open a window in the room?

The sentry is actually a safe. Heating system is oil boiler and forced hot water. Located in basement in the main part of house. Vents on totally separate chimney w/dedicated flue. The room the stove is located in is an addition, probably about 15 years old.

Opening a window doesn't seem to make a diff. I've cracked them when the space I'm in get's too hot. I'd like to knock out part of the wall behind the stove to get some heat back into the rest of the house. Aside from this addition, the house isn't very tight as it's 200 years old, post and beam construction, no insulation, just tar paper (probaly was done in the 40's when a major renovation was done). I have the attic about 1/2 insulate. Will complete when leaf season is done. Blowing cold air into the addition from main house right now.

 

[MountainStoveGuy]

Draft. No question. The oslo is there BEST drafting stove. I think we discussed this possibility in your pre oslo threads. If you had a tall 6 inch flue, that long horizontal might work. I also cant tell if there is any rise on that pipe.
Long horizontal pipe dumping into a 8x8 clay tile flue that isnt tall enough is a recipie for bad draft.

 

[Todd]

My 2 cents, reduce that long horizontal and 90 elbow by using 2 ea 45 elbows. If that doesn't do it install a 6" liner and your draft will definately increase over that 8" clay flue.

 

[Mike Wilson]

Draft. No question. The oslo is there BEST drafting stove. I think we discussed this possibility in your pre oslo threads. If you had a tall 6 inch flue, that long horizontal might work. I also cant tell if there is any rise on that pipe.
Long horizontal pipe dumping into a 8x8 clay tile flue that isnt tall enough is a recipie for bad draft.

I read the thread, and agree with this. If you can put a 6"" liner in the clay, do so. My Jotul had crappy draft the first year until I had a liner installed, now its wonderful.

-- Mike

 

[elkimmeg]

While all are suggesting liners. Measure this. besides little room to get it in there he is venting into an 8/8 exteriod demention flue just like 2/4's the 8/8 really measures 7.5 / 7.5"

the interior dementions is 6.75/ 6.75 not a whole lot of reduction to the cross-sectional area. No chance to line with insulation wrap. Really liners are best suited to solve much larger
cross-sectional situations,very rarely will there be much inprovement inan 8/8 clay flue. I think this situation suffers from the 2 90's longer than usual; horizontal length pitch is minimal and in doubt, and probably not enough verticle rise. A liner will not make up for them 2 90's or lack of verticle rise. What is the minium verticle rise required?

 

[senorFrog]

I really appreciate everyone taking the time to read through my draft issues.

Unfortuneately, The long horizontal run has to stay. If you notice the thru-wall thimble extends out enough that 2 45's would hardly do anything. I can pitch it more but's already pitched well over 1/4 inch. I put a level to it and measured the diff.

MSG, would an outside air kit help?

Elk, I agree, inside dimension is 6.75 x 6.75. Installer said liner would be a tough squeeze even w/out insulation.

Up for suggestions re a solution. Rebuild the ugly masonry blocks w/brick using proper liner size, air space, insulated and higher in the summer? Convert to class A?

Thanks again folks.

 

[MountainStoveGuy]

14'

 

[MountainStoveGuy]

extend your chimney, deduct 5 feet from the current setup for one elbow, the first elbow is not considered a penalty. if you have a net 8' chimney, then you need to add 6 more feet.

 

[elkimmeg]

minium verticle rise would be 24' 14 min per stove manufactures specs amnn 5" more for each 90 elbow

Probably should be 26-28'