Jotul 500 cracks and leaks

[Thomas Lilli]

Hi All,

I'm new to this forum and have a question for 500 operators. I've owned two 500 stoves in the last four years. My first suffered a cracked floor to which I was given a replacement sans warrantee and strict instructions to not fire the stove with the ash pan door open. The second stove failed the first year of operation at the same location, aft right floor corner from ash grate to right rear corner.

I can attest to never firing stove with door open.

Do any of you know that, in fact, your stoves are crack free? I am beginning to think many if these stoves have floor cracks.

It is my suspicion that, even with an airtight ash pan door, because the burning wood lays on the ash pan grate, it expands at a rate faster than the stove, loading and stressing the floor resulting in a crack. Both times my stoves broke, temperatures were around 350-400 degrees. Not hot by any measure. I can understand the theory that leaving the ash pan door open might contribute to this only if the increased airflow allows over firing to very high temperatures and high rate of local expansion of the ash pan grate causing stress to the floor and high rate of expansion of the floor if enough heat were generated on the floor. I did notice one unusual thing about stove 2 prior to failure. The ash pan door lever would spring back about half way from full closed. I always made sure. The door was closed but the friction spring seemed to keep the handle from staying fully to the right. I wonder if this allowed enough air to pass the door and cause the floor to fail.

I subsequently had the stove rebuilt with new a floor under supervision of Jotul at my dealer. The stove now has air leaks along the seam in the floor. We have yet to resolve this issue.

With all the head aches, I really like the jotul but I'm getting tired of the extreme caution required to operate it. I've flown jet airplanes that were less sensitive than this stove. Just wondering if anyone has had similar problems.

 

[stovelark]

Hello- Sorry to hear about your woes. It is quite unusual for an Oslo to crack without a leak from the ash pan housing area. It would or should have been quite a noticeable operating aspect, that slowing down the airflow via the air control switch was not happening (the leak letting in extra air). The Oslo is the most popular cast stove Jotul sells and is most people's favorite. It is also quite robust, it heats well, long burn times, holds large amounts of wood etc etc, a homerun stove. There's a chance one might not get an ideal stove once in a while, but two of the same stove, of that stove's caliber?? Hard to believe. Get it fixed, she is well worth it. Having sold Oslos for many years (and burning one for 8 seasons), its a favorite for sales people and consumers. Good luck to you.

 

[begreen]

Bummer Thomas. We had a time with our Castine where it became less controllable. I found the culprit to be ash packed in the back of the ash pan housing. This pushed the ash pan forward slightly which prevented the ash pan door from closing tightly. I can see if that condition was ignored where the grate or base might crack.

How much of an ash bed do you usually leave in the stove?

 

[Thomas Lilli]

Bummer Thomas. We had a time with our Castine where it became less controllable. I found the culprit to be ash packed in the back of the ash pan housing. This pushed the ash pan forward slightly which prevented the ash pan door from closing tightly. I can see if that condition was ignored where the grate or base might crack.

How much of an ash bed do you usually leave in the stove?

I dump the ash pan when the ashes become flush with the grate. I always leave the main door open when opening the ash pan door and close the ash pan door when dumping the pan.

 

[firefighterjake]

Well I cannot say with 100% certainty that right now there are no cracks . . . but in my pre-season check this Fall there were no issues.

You already know about the ash pan door being a no-go.

Like BeGreen mentioned the Oslo has a great ash pan set up, but some ash can and will build up behind the ash pan over time. You may still be able to fit the pan into the ash pan slot, but sometimes with a build up of just a bit of ash it will not allow a good seal on the ash pan door. I make a habit every time I dump the ash (typically like you when the ash pan is full to the brim) to take my ash shovel and clean out the back before replacing the ash pan. It is surprising how much ash can build up back there.

 

[My Oslo heats my home]

I've been burning in an Oslo for many years now and have had only one issue, my top oval cracked. But after a jotul rep's inspection it was found the cast was bad. It was replaced and nothing new to report.
I have seen some pictures of Oslo's with cracked floors but the culprit was found to be the open ash pan door, overfiring.

I can also understand what BG and Jake are saying with the ash pan pushing a bit on the ash pan door, there maybe some air leakage there.

Other than a bad cast or the ash pan door, I can't think of what else would cause that...

 

[Thomas Lilli]

Well I cannot say with 100% certainty that right now there are no cracks . . . but in my pre-season check this Fall there were no issues.

You already know about the ash pan door being a no-go.

Like BeGreen mentioned the Oslo has a great ash pan set up, but some ash can and will build up behind the ash pan over time. You may still be able to fit the pan into the ash pan slot, but sometimes with a build up of just a bit of ash it will not allow a good seal on the ash pan door. I make a habit every time I dump the ash (typically like you when the ash pan is full to the brim) to take my ash shovel and clean out the back before replacing the ash pan. It is surprising how much ash can build up back there.

Been pretty careful about cleaning the ash pan housing. I'm beginning to believe it may have been the ash pan latch spring keeping the latch from making an airtight seal on the door.

It's rebuilt now with new floor but a few leaks around the seams. I asked the dealer if, instead of rebuilding in their shop would Jotul do it. The response was sure....for $1500. I've already spent a grand to have it rebuilt once, only to get it back leaking worse than with the cracked floor. I can't see another $1500. The dealer is great, they want to de-mate and reseal the stove again. Feel bad that they are going to tie up their tech but, I'm getting no more than about four hours out of the stove. I have six cords standing and, at that rate, I will be out by the new year.

 

[My Oslo heats my home]

I would say as long as Jotul will back your dealers work then tie up the tech. For $1500 you can get your entire Oslo rebuilt. I can get a new Oslo in MB for $2200.

 

[acesneights1]

I have had mine for 7 yrs and had many times used the ash door to get it going although I always baby sat it. I don't do it anymore since joined here and learned better but mine knock on wood has not had any issue that I know it. How would I know if it was cracked. I usually clean it out good every fall and look as best I can. Where would the crack be and how big if I had them ? My air control does affect the flame althoug not dramatically. Also is it possible to burn the stove too hot ? How do you know what the threshold is ? I have always kinda just looked at the flame and if it looked like it was really cranking I would cut the air back.

 

[Thomas Lilli]

I have had mine for 7 yrs and had many times used the ash door to get it going although I always baby sat it. I don't do it anymore since joined here and learned better but mine knock on wood has not had any issue that I know it. How would I know if it was cracked. I usually clean it out good every fall and look as best I can. Where would the crack be and how big if I had them ? My air control does affect the flame althoug not dramatically. Also is it possible to burn the stove too hot ? How do you know what the threshold is ? I have always kinda just looked at the flame and if it looked like it was really cranking I would cut the air back.

You'd find low burn times and uncontrollable heat if the crack were large. The floor cracked from the right aft corner of the ash pan grate towards the right aft corner of the stove. Both times it was identical. At first you can just see the line in the casting. By the end of the season, it opened up pretty severely. Could not miss it. My chimney is about thirty feet with substantial draft. Might consider a damper.

 

[Thomas Lilli]

Also, at present, with the leaks not associated with the floor, I get about 550-600 degrees with the air valve fully in the low position.

 

[My Oslo heats my home]

that doesn't sound right, with the air all the way to the left you should be in the 300's-400 max.

 

[Thomas Lilli]

Yes,

I know, I have some leaks along the seam where the stove was re-assembled at the floor. Waiting to hear what the company is going to do.

Thanks.

 

[webby3650]

My chimney is about thirty feet with substantial draft. Might consider a damper.

Perhaps this could be part of your issue. That's a very tall chimney! Overdrafting is a serious concern at 30'!
I have had 2 service calls this year on Jotul's that had ash packed in behind the pan, preventing the door from closing. I clean and inspect several Oslo's each year that have been in service for years that have no cracks. This is the first time I have heard of an Oslo cracking, it's definitely not a common issue. For it to happen twice, I'd have to think that it has something to do with your set-up.

 

[Thomas Lilli]

I'm thinking I need a damper in my chimney.

 

[begreen]

How tall is it?

 

[Thomas Lilli]

Probably 25-30 feet.

 

[begreen]

A key damper wouldn't hurt if it's 30ft.

 

[My Oslo heats my home]

I also have strong draft issues, I picked up a damper a couple days ago.

 

[Thomas Lilli]

Can someone describe to me, the process that is taking place in the combustion chamber of these stoves?

I am assuming as the emperature rises to about 500, you get gassification that improves heat and combustion efficiency thereby "bootstrapping" the combustion process. In other words, the hotter it gets, the more efficiently it burns, thereby reducing the amount of 02 required per btu thereby increasing the temperature per unit volume of 02.

Is that a correct assumption?

 

[logger]

Been running our Oslo for a while now. Never heard of an Oslo cracking that wasnt overfired. Ive had temps above 700 a bunch of times and never experienced cracking. Another possibility is perhaps your dealer got a few bad apples, but that doesnt really sound like jotul to me. Try the damper and best of luck.

 

[Thomas Lilli]

Been running our Oslo for a while now. Never heard of an Oslo cracking that wasnt overfired. Ive had temps above 700 a bunch of times and never experienced cracking. Another possibility is perhaps your dealer got a few bad apples, but that doesnt really sound like jotul to me. Try the damper and best of luck.

And that would be? (Worlds best bird dog)

 

[KeithO]

I have not owned a Jotul, but had a Morso which has many similar design features. Today I have a Pacific Energy T5, a welded steel stove with cast iron cladding. Frankly, I think this concept is more durable, since the cast iron parts are way cooler on this stove and the steel plate firebox is welded tight and the parent material is ductile so much less chance of cracking.

I think the chimney length / draft issues that were raised are valid. I too have a 30'+ chimney, perfectly straight and all but 4' inside the house envelope. I made the mistake to not put in a second damper when I installed my stovepipe, the first is about 7" above the stove outlet. My stove is still marginal with the single damper. On really cold nights it can be difficult, even with the damper fully closed to prevent a runaway. Supposedly dampers are more effective if they are installed as high as you can get them above the stove, but my damper was retrofitted after the whole thing was installed.

So I have a theory for you: With your high draft, I suspect that you had a leak at one of the seams at the bottom of the stove and the extra air from that source cause a local overheating. That, over the entire season caused a crack. It does not sound like you have a dealer with a good stove mechanic. If you get the stove back with more leaks than they got it with, that is no doubt going to fail even faster than the original.

IF, you get the stove fixed properly and sealed up tight, then for sure put in Min 1 and I suggest 2 dampers as high as you can reach (you have to open them before opening the door), then your draft control issues will go away. If you notice any air leak, let the stove cool down and get some stove cement in there inside and outside to seal it up. Just follow the curing instructions. Don't allow any leak to persist in a cast iron stove, or it will warp or crack.

 

[acesneights1]

My chimney is about 20 ft. Ranch. I have mine going through a 6 inch liner up the masonry chimney but mine is not straight. It comes off the stove 90 then 90 up into the chimney with 2 45's to get around the damper. Maybe this worked out good after all. I thought I had too many bends but the stove place gave it the ok.

 

[webby3650]

In other words, the hotter it gets, the more efficiently it burns,

That's exactly right. Non-cat stoves are operating at their highest efficiency from a medium to high setting. That is what makes a cat stove so desirable, it runs it's most efficient on a medium to low setting. Stoves spend most of their time on medium to low if it's properly sized for the house.

In your Oslo, pre-heated air is being sent through the tubes at the top, mixing with smoke and allowing it to re-burn. Therefore, some pretty high firebox temps are required for this to take place.