Hi all. New member here. Joined so I could ask a question and learn about my new woodstove.
My family just bought a vacation house up in the mountains north of Boise. It's a fairly well-insulated 2,600 sq ft single story structure built in 1998. The previous owner (and original owner who built the house) was an electrical engineer who was a perfectionist with how the house was designed and built, researching every last detail. He selected an FPX 36 to heat the house, a great choice by most accounts.
We've been up at the house several weeks this winter and have been using wood heat almost exclusively as propane is much more expensive. The wood heat works great and is able to carry the whole heating load even down to below zero temperatures .. as long as you keep the fresh wood coming and the fire burning hot...
I have a few questions about the operation of the stove (or should I call this a "zero-clearance stove or fireplace?), the Air Control in particular, and whether it controls outside combustion air supply or not. I don't really understand the design and function of the combustion air supply. From reading the manual, it seems clear the stove uses outside air for its combustion. The blower duct supplies outside air to not only the area around the firebox that is heated and blown into the room, but this same duct also supplies the combustion air. The manual is unclear on this, but I think that's right. There are also "cooling vents" but those just cool the outside of the whole fireplace and the chimney and aren't connected to any of the air supplies that are actually used by the stove.
But then the confusion is: if the blower supplies the combustion air, then what does the Air Control do on the front of the fireplace? It is connected to a long thin metal bar that when moved to the left, slides down and exposes a series of little holes, and when slid to the right, covers them up most of the way but not all the way. The manual goes on to say the Air Control is what controls the combustion air and the burn rate, which when I have experimented, is what happens. The Air Control lever doesn't seem to be connected to anything else inside, it's just the think metal slide bar that flops around when you jiggle the control. It does jam easily, but I'll figure that out later.
So what exactly does the Air Control lever do, and where exactly does the combustion air come from? If I close the Air Control completely, does that force the stove to use outside air via the blower duct? And when it's open, it allows a much greater quantity of air to be sucked directly in via the little holes in the front of the stove? I've also seen posts that say the Air Control valve just controls the air wash air that keeps the glass clean and the little orifice that is at the bottom center of the firebox. When I slide the control to the right, it definitely does lower the burn, so does this mean that I am starving the fire for combustion air? And when the Air Control is closed, is the stove still sucking what it can through the blower duct, thus the blower duct acts like a constant minimum combustion air level and the Air Control simply adds more combustion air directly from the room? If so, then wouldn't running with the Air Control wide open, like with a hot fire, serve to defeat the whole "positive pressure" aspect of this stove?
I just want to understand the functioning of the combustion air supply so that I can better operate my stove in the most efficient and comfortable way possible. I've got other questions, but this one is the one that I am really anxious to get figured out first.
Great website and forum. Very impressed with the level of knowledge here and the spirit of helpfulness.
Darren
My family just bought a vacation house up in the mountains north of Boise. It's a fairly well-insulated 2,600 sq ft single story structure built in 1998. The previous owner (and original owner who built the house) was an electrical engineer who was a perfectionist with how the house was designed and built, researching every last detail. He selected an FPX 36 to heat the house, a great choice by most accounts.
We've been up at the house several weeks this winter and have been using wood heat almost exclusively as propane is much more expensive. The wood heat works great and is able to carry the whole heating load even down to below zero temperatures .. as long as you keep the fresh wood coming and the fire burning hot...
I have a few questions about the operation of the stove (or should I call this a "zero-clearance stove or fireplace?), the Air Control in particular, and whether it controls outside combustion air supply or not. I don't really understand the design and function of the combustion air supply. From reading the manual, it seems clear the stove uses outside air for its combustion. The blower duct supplies outside air to not only the area around the firebox that is heated and blown into the room, but this same duct also supplies the combustion air. The manual is unclear on this, but I think that's right. There are also "cooling vents" but those just cool the outside of the whole fireplace and the chimney and aren't connected to any of the air supplies that are actually used by the stove.
But then the confusion is: if the blower supplies the combustion air, then what does the Air Control do on the front of the fireplace? It is connected to a long thin metal bar that when moved to the left, slides down and exposes a series of little holes, and when slid to the right, covers them up most of the way but not all the way. The manual goes on to say the Air Control is what controls the combustion air and the burn rate, which when I have experimented, is what happens. The Air Control lever doesn't seem to be connected to anything else inside, it's just the think metal slide bar that flops around when you jiggle the control. It does jam easily, but I'll figure that out later.
So what exactly does the Air Control lever do, and where exactly does the combustion air come from? If I close the Air Control completely, does that force the stove to use outside air via the blower duct? And when it's open, it allows a much greater quantity of air to be sucked directly in via the little holes in the front of the stove? I've also seen posts that say the Air Control valve just controls the air wash air that keeps the glass clean and the little orifice that is at the bottom center of the firebox. When I slide the control to the right, it definitely does lower the burn, so does this mean that I am starving the fire for combustion air? And when the Air Control is closed, is the stove still sucking what it can through the blower duct, thus the blower duct acts like a constant minimum combustion air level and the Air Control simply adds more combustion air directly from the room? If so, then wouldn't running with the Air Control wide open, like with a hot fire, serve to defeat the whole "positive pressure" aspect of this stove?
I just want to understand the functioning of the combustion air supply so that I can better operate my stove in the most efficient and comfortable way possible. I've got other questions, but this one is the one that I am really anxious to get figured out first.
Great website and forum. Very impressed with the level of knowledge here and the spirit of helpfulness.
Darren
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