What is wrong with my Jotul F600?

[garybeck]

I bought a used Jotul F600 about a year ago. I did some research and specifically looked for one of these because it was touted as one of the biggest wood stoves on the market and had good reviews, plus Jotul just has a great reputation. After a year of use, I am disappointed:

• I can barely get it over the 300 degree mark on the thermometer into the burn zone
• it seems to EAT wood. The specs say it burns for 6 hours or something like that. that is a joke. I'll fill it up, close down the air, and if it burns for a couple hours before needing wood again, that's about the best it will do. I have to wake up 2 or 3 times a night to keep it going.

Before this I had an old Garrison stove. When I had a fire with that, it turned the room into a sauna. It got so hot people couldn't even sit in the room for very long. I kept a pot of water on the top and it would boil away. I could cook on there and food would burn. I thought this Jotul would be a major upgrade and I would have more heat and longer burn times, but I have neither. I put water on the top and it barely forms little bubbles. The stove barely keeps the small room warm and there is not enough heat to spread to the rest of the house.

It seems to light OK and i has decent air flow. There is a longer section of horizontal exhaust that was not there before with the Garrison (the Jotul exhaust is higher up so I had to set it on the floor in front of the hearth instead of on it). But I followed the specs for the minimum slope and it's only a couple feet.

I've read that you should really heat up the stove every once in a while, get it into the high side of the burn zone, and it will burn off some of the creosote in your exhaust/chimney. I used to do this with my old stove but I can't with this one. I can barely get it over 300 into the burn zone at all no matter what I do.

I occasionally can see the secondary burn tubes doing their thing, but not very often. somtimes it does look like it is burning the air coming from them but other times it looks more like the flames are being pushed *around* the incoming secondary air, and not actually burning. Regardless, I would think that even without the secondary burn, I should be able to get this stove up to 500 degrees without too much trouble.

Does anyone have any advice on what could be going wrong here? or did i just buy the wrong stove?

Thanks.

 

[begreen]

First thought is weak draft. The F600 will need stronger draft than the old Garrison and adding the horiz run is thwarting this. Is there an insulated stainless liner in the chimney? If yes, does it go to the top? What diameter is it and how tall is it?

 

[garybeck]

First thought is weak draft. The F600 will need stronger draft than the old Garrison and adding the horiz run is thwarting this. Is there an insulated stainless liner in the chimney? If yes, does it go to the top? What diameter is it and how tall is it?

there is a stainless steel liner in the chimney. I don't know that it is "insulated". It is a typical liner that goes in most chimneys when they find a cracked tile.. I had it installed professionally several years ago.
The exhaust on the stove is smaller than the liner so I have an adapter. I believe it is 6" coming from the stove and 8" on the chimney. the adapter is near the stove, before the horizontal section. I don't think I have a major draft problem. I see air flow and I can start fires fairly well, and I would think if there wasn't enough air flow the problem would be that I can't start a fire or it burns too slow. I do have a little trouble getting a fire started sometimes but it's not too bad and usually it burns OK. my problem is it burns wood quickly and doesn't deliver much heat while it's doing so.

 

[begreen]

Going to 8" will reduce draft velocity. Approximately how tall is the liner?

 

[Nigel459]

I occasionally can see the secondary burn tubes doing their thing, but not very often. somtimes it does look like it is burning the air coming from them but other times it looks more like the flames are being pushed *around* the incoming secondary air, and not actually burning.

When I see this happen it's usually too much draft pulling too much cold edit: secondary air into the stove giving a cooling effect. The air/fuel/heat balance gets out of whack. Then I turn down the key damper in the stovepipe and voila, slow lazy flames and proper secondary combustion. Do you ever see slow lazy flames?

Also odd that the stove top temps are so low. That suggests wet wood. Newer stoves need dry wood, older stoves didn't so much...

 

[garybeck]

Going to 8" will reduce draft velocity. Approximately how tall is the liner?

goes like this:
1) rear/horizontal stove exhaust
2) 8" adapter
3) ~2 feet of horizontal run with slope
4) 90 degree elbow
5) straight up through the chimney in the middle of the heated house, through two floors and attic space. I'm guessing that is about 30 ft.

if i had a draft problem wouldn't the symptoms be different, like the fires would go out, and would be hard to start?

 

[begreen]

Also odd that the stove top temps are so low. That suggests wet wood. Newer stoves need dry wood, older stoves didn't so much...

That is the alternate possibility, or it could be both issues. With proper draft and seasoned wood this stove can really put out the heat.

 

[begreen]

if i had a draft problem wouldn't the symptoms be different, like the fires would go out, and would be hard to start?

Symptoms of weak draft for this stove would be weak or poor secondary combustion and smoke spillage when opening the front door. If this was a single story chimney that might be an issue, but unlikely with a 30' flue liner.

Has the wood been tested for moisture content?

 

[garybeck]

Symptoms of weak draft for this stove would be weak or poor secondary combustion and smoke spillage when opening the front door. If this was a single story chimney that might be an issue, but unlikely with a 30' flue liner.

Has the wood been tested for moisture content?

I have a moisture reader. I regularly check the wood going in. Not always perfect but most of the wood i put in there is under 15% moisture.

I do have poor secondary combustion, I think, just based on visual observation. I don't see it happening very much. sometimes itdoes look like flames coming out of the burn tubes but a lot of times it seems like the flames are burning around the air and and not actually burning it.

 

[moresnow]

How exactly are you using the moisture meter ?

 

[begreen]

I have a moisture reader. I regularly check the wood going in. Not always perfect but most of the wood i put in there is under 15% moisture.

Is this with wood that has been brought up to room temp, then resplit and tested on the freshly exposed face of the wood in the middle of the split?

 

[garybeck]

Is this with wood that has been brought up to room temp, then resplit and tested on the freshly exposed face of the wood in the middle of the split?

i can't say i've been doing all that! i usually just poke the probes on the end and if the red light beeps I toss that one aside and let it sit for a while longer

 

[bholler]

i can't say i've been doing all that! i usually just poke the probes on the end and if the red light beeps I toss that one aside and let it sit for a while longer

The actual moisture content of the wood is easily twice what you are measuring with that technique. What species is the wood and how long has it been cut split and covered?

 

[begreen]

i can't say i've been doing all that! i usually just poke the probes on the end and if the red light beeps I toss that one aside and let it sit for a while longer

End grain testing is meaningless. Wood dries from the outside, in. You need to test the core moisture of the wood. That requires resplitting.

 

[LiamFitzpatrick]

i can't say i've been doing all that! i usually just poke the probes on the end and if the red light beeps I toss that one aside and let it sit for a while longer

If you're not testing a new split on the core of the wood, your readings are worthless. You have to test the wood on the inside of a new split within the wood.

 

[Woodsplitter67]

sounds like wet wood..

 

[stovelark]

Would think wet wood too. Take a couple of bundles of softwood packs from a grocery store, or cut up some pallets and mix accordingly.
300 degrees on one of the corners of the Firelight top is the measuring spot? That indicates wet wood or poor draft. The Firelight is a pretty easy drafting stove. Any change in flame appearance with the air control being changed? If not, the stove could have an air leak.
A lighter going around the seams will find a leak pretty quick. But it sounds like wet wood, change the fuel and verify the issue... good luck, almost always, Firelights are awesome heaters.

 

[Caw]

Whenever I read these threads where the issue is wet wood/improper MC usage I always envision us smacking around the OP with pool noodles. We are Russell Wilson and they are Conan saying "no its dry" and the pool noodles are the truth....

 

[stovelark]

Caw, nice one! Well, its almost always the fuel, but its the easiest to prove as the issue too- just buy a couple of bundled softwood and light it up...

 

[paredown]

As an F600 owner, I would say you should check that the manifolds, cast iron top plates and burn assemblies are intact, and the fiberglass blanket that lays on top of the cast iron plates is present.

Also seals need to be checked.

The TL:Dr version of my history with our stove (also purchased used) was that the manifold/burn tubes were not functioning properly, and the cast plates were warped (not fitting together) and even the thermal blanket was in tough shape. All of this conspired to make the stove hard to get up to temperature (and our draft is angle out and straight up a liner)--6" to 8" liner.

Check for your stove (or post pictures) and check threads that I have started--one of them is my attempt to document the rebuild.

And it is worth saying that the rebuild will be regular maintenance--although I have been careful with the stove, the burn tubes are ready for another replacement--they are too fragile to do what the are supposed to, and survive bumps from splits when they are hot.

 

[MR. GLO]

Can you take a photo of the stove area?

Do you have anything near it like a heat shields on the floor or a pile of wood? Have you tried a fan blowing towards it from 10 feet away or open a window to see if you can get it up. One time I had a 4 foot by 35 inch decorative heat shield on the side about 18 inches away and it would stop me from getting the temps up. Many times it was because I didn't load enough wood.

 

[Billyboy]

I have this stove , I heat my whole house with it (2000sq ft.) it can be 10 degrees outside and I have the windows up. I can get the stove top to 600 degrees without even trying. I burn 2-3 year seasoned wood.
That stove is a beast!!

 

[Simonkenton]

You definitely have a problem and these gear heads will straighten you out. I have the Little Brother, the F 500 Oslo and the girlfriend and I love this stove. Easy to run it up to 600 degrees and we really give it a workout.

I must say though burn times are not great with this stove. Load it up with oak running at 450 and in a few hours you will be adding some more.
Load it with oak at 11 pm and go to bed, and in about 5 hours it won't be cranking much heat. Might be down to 200 degrees. Easy to load it up and crank it back up after five hours, however.

Anyway it is not perfect but it is a great stove. Watching those secondaries burn is magnificent. We pour a glass of wine, turn off the tv and spend hours just watching the beautiful Jotul wood stove.