Jotul F400 Air Control Question

[firehoo]

My new woodstove (F400 Single door) came with a small extra cast-iron "inspection cover" for inside over the air control lever in the center.

(Item 43 in the exploded view on p17. click here).

The one installed in the stove says "USA" and the extra one says "EUR."

what does it do? What's there to inspect?

I assume there's some regulation EU vs US that requires some odd geometry or function one way or the other....anyone know what the diff is? And/or why?

Restrictor plate of some kind? Is this an EU vs CARB vs EPA thing? UL vs CE?

Just wondering. Thanks!

 

[begreen]

Yes, different standards. The US cover is for EPA. It covers the air control slider valve.

 

[firehoo]

Thanks BG.

So any idea what the difference is? Does the EU one allow hotter/leaner or what?

 

[begreen]

If I remember right it had an extra air hole in it. I tried it for a week and decided the US unit seemed to burn cleaner based on watching the stack, so I put that one back on and left it that way.

 

[dvellone]

I also purchased a new castine several months ago and wondered about the same thing.

The USA cover has two approximate 3/8" round openings at the left and right side of the inspection cover while the Europa cover has a larger slot opening at the center of the inspection cover.

While the air control allows varying amounts of air to enter the firebox, these covers would seem to maybe only make a difference in terms of the location that the air is directed towards in the firebox.

Wouldn't their size difference also regulate how much air is entering the stove? If so, I'd think that with the Europa cover you couldn't choke down the stove as much as the USA cover.

 

[firehoo]

Interesting. I wish I had a schematic of how all the chambers and plenums work in it. The exploded view isn't altogether clear about how it works.

 

[polaris]

Mine has a bolt in each hole. Should one of them be open?

 

[dvellone]

Mine has a bolt in each hole. Should one of them be open?

Maybe you're thinking about the the mounting holes located on the top of the cover. The air holes are facing the back wall of the stove. They're on the continuous leg of the cover that rests on the firebox floor.

 

[firehoo]

"The air holes are facing the back wall of the stove. "

So where does the "airwash" air come from? I thought this slider valve allowed air in from the front to go into the side-wall channels up to the top to come down over the glass to keep it clean.

 

[polaris]

Mine has a bolt in each hole. Should one of them be open?

Maybe you're thinking about the the mounting holes located on the top of the cover. The air holes are facing the back wall of the stove. They're on the continuous leg of the cover that rests on the firebox floor.

That is exactly what I'm thinking about. I'm not able to picture what your talking about. Do you know what # it is on the exploded diagram?
Sorry, I see the # now.

 

[polaris]

So it is part of the cover it's self, or part of the base on which the cover rests?
Joe

 

[dvellone]

"The air holes are facing the back wall of the stove. "

So where does the "airwash" air come from? I thought this slider valve allowed air in from the front to go into the side-wall channels up to the top to come down over the glass to keep it clean.

I don't know. The pathway for exhaust is towards the glass and upwards of course, so I really don't know exactly how the airwash works. I'm sure there's much more to the dynamics of the stove design than I understand, but it doesn't make sense that the air would enter, making it's way up to a point above the glass and then not just exit towards the flue rather than washing down over the glass. I thought, observing the fire that the airwash had somewhat to do with the dynamic of the fire rolling out towards the glass and burning off any formation there. I have noticed at least in my circumstance that the airwash on my castine isn't as effective as that on my brother's f600.

That cover has to be like the fine mixture adjustments on a carb. I wonder though what the EU and US difference is. Who is allowed the lesser efficiency and which cover are you better off with. Must be negligible if they provide you with both.

 

[dvellone]

So it is part of the cover it's self, or part of the base on which the cover rests?
Joe

I think the cover is has two functions; to keep debris out of the air control and to either direct and restrict airflow or just one or the other.

The engineering of these stoves is fascinating to me. I used to burn an ancient box stove which heated my house easily but also went through wood at least 10x the rate that I burn today. I never had any creosote in the chimney but the average temperature of my neighborhood was probably warmer than it is today.