Jotul 550 Primary Air Modification

[jatoxico]

First off thanks to EJL923 for the tips. Was going to put this in the 550 thread but maybe others will find something useful.

The primary air slider on my stove did not travel to the end of the slot that retains the slider knob. I removed the slide and on inspection the slide hits a stop preventing maximum closure of the air.

Users of this stove know it allows alot of air into the box. When I have been running and draft is rolling it feels like you want to limit the air coming in more than you can. Burn times are decent 5-6 hrs but probably could be better so I looked into ways of gaining more control of the air.

The center opening is designed (angled) so that it cannot be fully closed but by removing material on the slider it could travel farther making the center slot smaller when fully closed. *I also noticed that the other square slots that are meant to fully close were not shut completely.

I removed close to a 1/4" of material. This shut the square slots fully and caused the center slot to be much smaller. Once back together I am getting full travel in the slider retaining slot.

Testing begins tomorrow.

*Edit; I should say the it was only 1 or 2 of the 6 square slots that were not fully closing. They were on the same side of the manifold (unequally distributed) and it did not appear to be an intentional part of the design but more of a casting issue.

 

[pen]

Let us know what the chimney looks like in a few weeks time.

pen

 

[jatoxico]

Let us know what the chimney looks like in a few weeks time.

pen

So long as I adjust based on temp and how the fire is burning I don't anticipate any issues. Anyone can smolder a fire by shutting down too far or too early but when hot my draft pulls in too much air and I easily go to 700-750 or more when I would rather run an hour longer at 600.

 

[pen]

But, still worth checking the chimney as even with an EPA stove, many report closing things down (without modification) and having a good hot burn, but find smoke towards the end of the cycle.

It's a tough balance sometimes.

pen

 

[jatoxico]

But, still worth checking the chimney as even with an EPA stove, many report closing things down (without modification) and having a good hot burn, but find smoke towards the end of the cycle.

It's a tough balance sometimes.

pen

Well that I agree with. I don't shut the air down fully overnight just for that reason, I like a decent amount of air going in to burn down the coals cleanly and keep heat going up the chimney. In fact I rarely shut the air down fully per manufacturer recommendation.

However there are times I need to limit air more. I don't know if Jotul intentionally limited the slide for the US market or if its just a QC thing being cast iron and all but the slide knob was only traveling 8/10 ths of the available slot. Full open but not full close.

 

[pen]

Are all your splits pretty equal in size, or do you leave some lunkerz (big ones)?

I never used to be a fan of big splits, but now that I've gotten onto a 2.5 to 3 year cycle before burning wood, I find that I really like a few big splits mixed in with not so much surface area (yet they are still well seasoned) just to help moderate temps a bit with a big load.

I find with a big seasoned split, it has less surface area and doesn't give up it's goods as quickly as the smaller stuff does and helps me out when loading on fairly hot coal beds or just when I need things to last a bit longer.

Up until I let things dry as long, I used to curse large splits.

pen

 

[jatoxico]

Are all your splits pretty equal in size, or do you leave some lunkerz (big ones)?

I never used to be a fan of big splits, but now that I've gotten onto a 2.5 to 3 year cycle before burning wood, I find that I really like a few big splits mixed in with not so much surface area (yet they are still well seasoned) just to help moderate temps a bit with a big load.

I find with a big seasoned split, it has less surface area and doesn't give up it's goods as quickly as the smaller stuff does and helps me out when loading on fairly hot coal beds or just when I need things to last a bit longer.

Up until I let things dry as long, I used to curse large splits.

pen

I'm probably more like you used to be because very little of my biggest stuff is seasoned enough to burn well when I've tried. I'm burning 2 yr seasoned wood this year and any of the big stuff I left is still a bit wet. Will mostly be the same next year unfortunately but after that I will be burning all 3 yr seasoned wood and then we will see. I see some of the splits people burn and wonder how they can burn them down cleanly, not there yet.

 

[terpsucka]

Thanks for all the info jatoxico. I have been thinking about making the same mods to my unit, but haven't gotten around to taking it apart yet. So the material you removed-- did you remove it from the part of the slider that sticks out of the front of the insert, the part you actually touch to open it and close it?

 

[jatoxico]

Thanks for all the info jatoxico. I have been thinking about making the same mods to my unit, but haven't gotten around to taking it apart yet. So the material you removed-- did you remove it from the part of the slider that sticks out of the front of the insert, the part you actually touch to open it and close it?

The part I filed can be seen in pic 3-5. (*the slide in pic 3 was originally square the notch was filed in) In pic 5 the slide is resting against the stop on the air wash manifold. Removing the material allowed full movement/travel of the slider that sticks out the front. There are other posts in the 550 thread (on pg 12?) of others who looked into this.

When did you get the insert? Depending on the age of the insert the slide configuration varies. In the end you will likely have to pull it to see what you got.

Since doing it conditions have only been right once to where I needed/could shut down fully but it was great to have the extra control.

 

[terpsucka]

Thanks, that makes sense. I bought my unit new this spring. I definitely have the "doesn't close all the way configuration", but my slider might be a bit different from yours. I'll open it up in the offseason to see what I have. I haven't had a problem with it yet... I'm still in the "building up the wood supply" phase, but I seem to have some pretty serious draft, and I could see it being a problem once I'm working with consistently good, dry wood.

 

[jatoxico]

Thanks, that makes sense. I bought my unit new this spring. I definitely have the "doesn't close all the way configuration", but my slider might be a bit different from yours. I'll open it up in the offseason to see what I have. I haven't had a problem with it yet... I'm still in the "building up the wood supply" phase, but I seem to have some pretty serious draft, and I could see it being a problem once I'm working with consistently good, dry wood.

That sounds like a good approach. You can't evaluate it properly w/o good wood.

 

[leakypuppy]

How much disassembling of the stove is required to make these modifcations? Do you need to pull the stove from the hearth?

First off thanks to EJL923 for the tips. Was going to put this in the 550 thread but maybe others will find something useful.

The primary air slider on my stove did not travel to the end of the slot that retains the slider knob. I removed the slide and on inspection the slide hits a stop preventing maximum closure of the air.

Users of this stove know it allows alot of air into the box. When I have been running and draft is rolling it feels like you want to limit the air coming in more than you can. Burn times are decent 5-6 hrs but probably could be better so I looked into ways of gaining more control of the air.

The center opening is designed (angled) so that it cannot be fully closed but by removing material on the slider it could travel farther making the center slot smaller when fully closed. *I also noticed that the other square slots that are meant to fully close were not shut completely.

I removed close to a 1/4" of material. This shut the square slots fully and caused the center slot to be much smaller. Once back together I am getting full travel in the slider retaining slot.

Testing begins tomorrow.

*Edit; I should say the it was only 1 or 2 of the 6 square slots that were not fully closing. They were on the same side of the manifold (unequally distributed) and it did not appear to be an intentional part of the design but more of a casting issue.

 

[begreen]

I'm glad you found this thread. Was thinking about you as I reread it. Most folks would not want to do this mod, but if the insert is connected to a very tall flue with strong draft this may be a solution toward better control.

 

[OhioBurner©]

That reminds me I've been meaning to do this. I did try to remove the top trim once to check this out but it wouldn't budge. Can't remember if maybe I missed a bolt or two though, or if it was just seized in there good. Will have to try again sometime. My Rockland likes to run hot, seems I rarely ever run it other than slider all the way closed off. Unless I am burning not seasoned enough wood or need extra heat. 22' (I think) straight up double wall duravent in my interior chimney.

leaky... no I don't believe you need to pull the insert for this. Just take off the cast iron trim piece above the door on the front face (what the air slider is in). The nuts should be in the corners inside the firebox but I'm not sure off hand how many there are.

 

[leakypuppy]

Can anyone who's attempted this modification offer any insight on how this beast comes apart? I've removed the nut (#15) in the attached parts diagram but the cover (#69) is held fast.

Thanks!

 

[jatoxico]

All I recall having to do is remove the nuts (#15) that you already mentioned. There are two (one each side). Once they are off you probably just have to break it free, few taps on the back of the housing with a plastic mallet or similar should do it IIRC.

Edit, just checked an old post and according to that there are 3 nuts/bolts holding the plate and housing on.

 

[EJL923]

In my case, the primary mod didn't do too much, but still worth doing. Another thing is looking at your doghouse air. My model had two roughly 1/8" holes. I put a screw in one of them which helps a lot. The last thing and hardest to do is the secondary mod slider. I think it was you who asked for pictures. I have to find them on my old computer. this requires pulling the stove

 

[jatoxico]

In my case, the primary mod didn't do too much, but still worth doing. Another thing is looking at your doghouse air. My model had two roughly 1/8" holes. I put a screw in one of them which helps a lot. The last thing and hardest to do is the secondary mod slider. I think it was you who asked for pictures. I have to find them on my old computer. this requires pulling the stove

Been meaning to ask you about that EJL. Did you drop the drop the screw in from the top or remove the heat shield to access those holes? Would be nice to have some way of adjusting that with the door closed. My flue was in great shape when I last did a cleaning so I think I can risk cutting the air a bit more when conditions are right.

 

[EJL923]

just dropped a loose fitting screw from inside. I found one hole blocked was good enough for me. Two was too much, its nice having one little rocket booster for those big splits and low coals.. i looked at making it adjustable from outside, just not a lot of room. I suppose you could put a magnet across the hole from outside and slide to adjust

 

[OhioBurner©]

just dropped a loose fitting screw from inside. I found one hole blocked was good enough for me. Two was too much, its nice having one little rocket booster for those big splits and low coals.. i looked at making it adjustable from outside, just not a lot of room. I suppose you could put a magnet across the hole from outside and slide to adjust

Are you talking about your doghouse air or one of the other mods? I blocked both the holes in my doghouse air... depends on the species of wood what your coal situation is like. I'm burning ash and eco-bricks this year and with both holes blocked I burn the coals down to powder easily. With black locust I'd get a lot of buildup of coals with both blocked.

 

[leakypuppy]

Thanks to some clarifications by jatoxico I was able to complete the modifications. I was mistaken in my earlier post when I referred to the nut #15 and the cover #69 so please disregard that information. To be clear, the part you are removing is the Air Wash Manifold (#33) in the attached parts diagram. It is held in place by 3 M6 bolts -- 2 (#32) on each side and 1 (#34) in the center -- that have a 10mm head. The gasket on my manifold fell off in the process and needed to be replaced. I was lucky to find a Jotul gasket kit locally that included the .250 rope gasket with self adhesive tape (#40) so I didn't have to wait. I used a Dremel tool with a stone grinding tip to remove material from the end of the Air Slider allowing it to slide further to the left which reduces the amount of air when the slider is in the closed position.

After getting everything back together I did notice an improvement but not as much as I'd hoped for. My secondaries still don't engage that much -- nothing compared to the secondary burn I get with my Hearthstone Homestead. Just to rule it out I'm going to replace the gaskets on both the door and the glass -- they came with gasket kit so I might as well -- and then maybe I'll try and figure out where the doghouse screw holes are and experiment with that.

-LP

 

[leakypuppy]

In my case, the primary mod didn't do too much, but still worth doing. Another thing is looking at your doghouse air. My model had two roughly 1/8" holes. I put a screw in one of them which helps a lot. The last thing and hardest to do is the secondary mod slider. I think it was you who asked for pictures. I have to find them on my old computer. this requires pulling the stove

Is the doghouse the air intake in the front center of the firebox floor? Do the screws get insert from underneath?

Thanks!

 

[OhioBurner©]

Yeah they are on the back side of the hump in front center of the firebox. Just reach in there and put a screw into it - no disassembly needed. Use a little mirror to see it easier if you want.

 

[Stoneseller]

Interesting read. I think I finally understand the workings of the slider & the modifications required to make it close all the way.

The doghouse air has me perplexed. Prior to the start of burning this winter, I had removed the entire front of my unit to replace a badly warped & cracked stove floor (part #19). In the process I also removed the interior insulating panel (part #20), and thoroughly vacuumed & brushed the floor of the stove.
I totally missed seeing any air holes in the floor. I need to look from the underside as per OB, Minister of Fire.

My biggest misunderstanding of this unit is the air flow that blows out the secondary tubes. The parts diagram does not show what I'll call the rear air riser channel, which connects to the upper rear channel, which connects to the upper side channels.
This is obviously all fully welded heavy steel stock, and a fixed part of the fire box. I can see a notch at the bottom of the rear shield, and something called the secondary air channel.
I never really looked at the back of the stove pre-installation, so I will assume there is a small rectangular opening near the bottom of the stove, facing the back wall of my fireplace. Part #13 must be the inlet cover of sorts, and #14 appears to be a gasket, even though it is described as a Blower Shield Assembly.

Does anyone ever think about the potential for this inlet to become restricted from accumulated debris, such as stink bugs or spiders, insulation fibers, dust, ash, mortar flakes, dog hair?