Jotul F400 Castine. Explain the air intake system for me.

[Frostbit]

Specifically, where the air enters the stove (all from the hole in the back bottom? Part?) Is the secondary air a "fixed" given? Where does it come from? I know I cannot shut the primary air down to "off"....there is always some. The glass airwash: where does this air come from? Its path through the stove? I can run a hot fire to clean most of the glass, but I always have two small crescents of black in the lower right and left corners of the door glass. (this is a single door model, new two months ago)

The draft intensity is compounded by high winds. Today it was blowing 40 mph, and the fire is much livelier, even with the primary throttled to idle. I cannot get the slow lazy flames from the coal bed to the primaries like I can when the wind is calm. There is no doubt the wind is affecting the fire. I do not have a damper. My stack total length is 14', and I am using a traditional capper.

Any info you can provide me on the air intake system, its path, primary and secondary air sources, etc, makes me a more informed and happy wood burner.

Thanks up front!

 

[Frostbit]

Sorry, that should read "I cannot get the lazy flames from the coal bed to the SECONDARIES", not primaries.

 

[TheFlame]

Specifically, where the air enters the stove (all from the hole in the back bottom? Part?) Is the secondary air a "fixed" given? Where does it come from? I know I cannot shut the primary air down to "off"....there is always some. The glass airwash: where does this air come from? Its path through the stove? I can run a hot fire to clean most of the glass, but I always have two small crescents of black in the lower right and left corners of the door glass. (this is a single door model, new two months ago)

The draft intensity is compounded by high winds. Today it was blowing 40 mph, and the fire is much livelier, even with the primary throttled to idle. I cannot get the slow lazy flames from the coal bed to the primaries like I can when the wind is calm. There is no doubt the wind is affecting the fire. I do not have a damper. My stack total length is 14', and I am using a traditional capper.

Any info you can provide me on the air intake system, its path, primary and secondary air sources, etc, makes me a more informed and happy wood burner.

Thanks up front!

I'm pretty sure the Castine has the same air setup as the Oslo, which means that the air is indeed all coming in through the air inlet in the back. The primary air (controlled by the front lever) comes around the bottom plate and enters through the air inlet in the front. When the primary air is open, the majority of the air is drawn through the primary air inlet. When you close the primary down, the air is drawn through the secondary burn tubes. You cannot control the air flow through the secondary, it has a factory set flow rate in order to avoid choking the stove down and letting smoldering occur (EPA compliance).

I have an Oslo with 27' of stack, and I have been considering trying out a pipe damper myself for those extra windy (overdrafty) nights. I'm not really worried about the decrease in draft from the damper, since I seem to have an abundance of it. I figure worst case I take it back out and put screws in the holes I make. I'm going to start with a probe type thermometer for my flue though to see what temps I'm getting when it's drafting hard. If you have only 14' of stack, I'm surprised you'd have an overdraft problem, but each installation is different it seems.

More importantly, you have a Blue Majolica stove???? I haven't seen this color yet. Pictures PLEASE!

 

[Frostbit]

Thanks for the information!. I kinda figured it pretty much as you described. I sure would like to see an air flow diagram from Jotul, much like one other stove manufacturers provide to their owners. I still am unsure about the glass airwash.

I don't really want to put in a damper. 95% of the time, not needed. I would rather perhaps make up a sliding plate to choke the air inlet hole in the back, not only for very windy times, but in the event I want to shut the stove completely down in an emergency (ie, stack fire...god forbid)

Yes, my stove is the blue majolica. It is pretty. Once I figure out how to get photos on here, I'll do that. I am a fabricator, and I made up a neat little short poker and ash rake to show as well. Too, I build sauna and camp wood stoves and have been asked for pics before.

Thanks for the info...stay warm!

 

[TheFlame]

I'm pretty sure the airwash is just air from the secondary burn tubes. As you shut down the primary air, the air from the secondary tubes moves in a circular pattern through the firebox, this creates the air wash effect. That's my theory anyway. You'll notice this happening if you get the stove roaring with flames, and then shut down the air completely. The flames will vigorously cascade down across the front of the glass.