# Sweet Home Stove not getting enough air



## weaslemama (May 1, 2020)

I have an older model sweet home apline afx stove that we just installed and it doesn't seem to be getting enough air when the door is closed. 
Chimney is all clear and brand new, double wall out of the stove into insulated so no obstructions there. 
Door is sealed with a gasket and closes tightly.  Maybe this is incorrect?  The stove came with a new gasket and glue but didn't have an old one in place so I actually just assumed that it needed to be put in (it has a groove that appears to be for gasket)  but our Fisher stove isn't supposed to have one so maybe this one isn't either but I can't really find any info on this stove and it did not come with a manual..... 

When the vents (sorry I don't know if this is the right word for it but the handle in front of the stove that you pull open to give the fire more air) are closed but the damper is open the fire smothers and the box fills up with smoke, when I open the vent there is clearly more air flow and it doesn't exactly smother but it doesn't stay going very well and there's a lot of smoke not drawing up the chimney.  If I crack the door a little it clears up and seems to be drawing quite well.

I have never installed a stove before and don't exactly know what I'm doing but have tried to follow all the codes and videos I can find on line and go slowly and carefully....any thoughts on what might be the problem would be greatly appreciated!


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## bholler (May 1, 2020)

weaslemama said:


> I have an older model sweet home apline afx stove that we just installed and it doesn't seem to be getting enough air when the door is closed.
> Chimney is all clear and brand new, double wall out of the stove into insulated so no obstructions there.
> Door is sealed with a gasket and closes tightly.  Maybe this is incorrect?  The stove came with a new gasket and glue but didn't have an old one in place so I actually just assumed that it needed to be put in (it has a groove that appears to be for gasket)  but our Fisher stove isn't supposed to have one so maybe this one isn't either but I can't really find any info on this stove and it did not come with a manual.....
> When the vents (sorry I don't know if this is the right word for it but the handle in front of the stove that you pull open to give the fire more air) are closed but the damper is open the fire smothers and the box fills up with smoke, when I open the vent there is clearly more air flow and it doesn't exactly smother but it doesn't stay going very well and there's a lot of smoke not drawing up the chimney.  If I crack the door a little it clears up and seems to be drawing quite well........
> I have never installed a stove before and don't exactly know what I'm doing but have tried to follow all the codes and videos I can find on line and go slowly and carefully....any thoughts on what might be the problem would be greatly appreciated!


How dry is your wood?


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## weaslemama (May 1, 2020)

bholler said:


> How dry is your wood?


Very dry, two years seasoned maple


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## coaly (May 1, 2020)

Make sure the flue pipe damper is installed correctly. The plate should be open when the handle is straight with the pipe.

Start it with flue damper open. Air intake wide open. Twist up some newspaper so it flares up and this heat rising up the chimney will start the draft.

What is the connector pipe configuration? Length of pipe before chimney, number of elbows, or horizontal  runs?

This is connected to a new insulated chimney? If so, what is the flue diameter? Is the stove a 6 inch outlet with 6 inch pipe into a 6 inch chimney?


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## begreen (May 1, 2020)

And, where is the stove located? Main floor or in the basement?


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## weaslemama (May 1, 2020)

Damper is all the way open. 

Yep started with paper to heat the pipe first. 

Stove outlet is 6 inch going into a 6 inch double walled 90 degree elbow which goes into insulated pipe. Insulated pipe goes through the wall of a yurt to a T, chimney is at least 1 foot probably 2 above the peak of the yurt. 

Total Length of chimney is 4 feet before chimney 

I suppose installed ground floor since it’s a yurt so only one level.....


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## weaslemama (May 1, 2020)

weaslemama said:


> Damper is all the way open.
> 
> Yep started with paper to heat the pipe first.
> 
> ...


 
Yes all pipe is 6” inner diameter


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## coaly (May 1, 2020)

Make sure the horizontal run from stove to wall is pitched uphill at least 1/4 inch per foot.

Is the yurt pretty much airtight? When the hot exhaust gasses rise up chimney, this creates a low pressure area in chimney, connector pipe, and stove. Atmospheric air pressure PUSHES into the intake or open door of stove feeding oxygen to the fire. Make sure outdoor air pressure can get inside to the stove intake. You may need to crack a window close to stove to get enough air pressure to push into the stove until chimney is hot enough to cause more draft. This low pressure area or vacuum created by chimney is due to differential temperature between inside and outside of chimney.  The larger the temp differential, the larger the pressure differential. This relates to stronger draft. So warmer weather and low pressure atmospheric conditions requires more heat in the flue to create the lower pressure needed to get air into the stove.
When you understand the principals that make the stove work, you can troubleshoot problems and why you’re not getting air into the stove.

Make sure your wood is dry. You should have a moisture meter and pipe thermometer (double wall requires probe type, not magnet surface mount thermometer) so you know what temp you’re running. The object is keeping flue temp above 250*f to the top when smoke is present. Below this critical temp, water vapor from combustion allows smoke particles to stick forming creosote.


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## weaslemama (May 1, 2020)

coaly said:


> Make sure the horizontal run from stove to wall is pitched uphill at least 1/4 inch per foot.
> 
> Is the yurt pretty much airtight? When the hot exhaust gasses rise up chimney, this creates a low pressure area in chimney, connector pipe, and stove. Atmospheric air pressure PUSHES into the intake or open door of stove feeding oxygen to the fire. Make sure outdoor air pressure can get inside to the stove intake. You may need to crack a window close to stove to get enough air pressure to push into the stove until chimney is hot enough to cause more draft. This low pressure area or vacuum created by chimney is due to differential temperature between inside and outside of chimney.  The larger the temp differential, the larger the pressure differential. This relates to stronger draft. So warmer weather and low pressure atmospheric conditions requires more heat in the flue to create the lower pressure needed to get air into the stove.
> When you understand the principals that make the stove work, you can troubleshoot problems and why you’re not getting air into the stove.
> ...



Ok all very helpful. It’s a warm day here and cloudy out so weather conditions could have been the issue because I started a pretty small “test” fire.... 

Do you mean that that the horizontal run of pipe should not be level but at an incline upwards towards the chimney?


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## begreen (May 1, 2020)

weaslemama said:


> Ok all very helpful. It’s a warm day here and cloudy out so weather conditions could have been the issue because I started a pretty small “test” fire....
> 
> Do you mean that that the horizontal run of pipe should not be level but at an incline upwards towards the chimney?


It's hard to get decent draft in a yurt when it's mild outside due to the short chimney. You might try eliminating the 90 and replace it with a pair of 45s making an offset. That will help a bit.


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## coaly (May 2, 2020)

Yes, since the chimney creates the low pressure measured as draft, the connector pipe, elbows, spark screen, and flue damper all create resistance. The more resistance, the higher the chimney needs to be to create the correct low pressure area  needed in the stove. Tilting the horizontal pipe upward toward chimney eliminates some resistance. The damper being a variable resistance  controls the velocity of rising gasses. Slowing the rising gasses is done to slow an over drafting chimney which affects the stove by slowing the intake air.

The length of the horizontal run is critical and the height of chimney rise from stove to top of chimney are the measurements needed to be able to tell if the chimney will create enough draft and how much the connector pipe configuration reduces the draft. Like a drain that runs downhill, or the water slows, the pipe needs to be uphill to keep the flow of lighter than outside air moving easily.

You stated the 4 foot chimney pipe before chimney. ... The pipe before chimney is  called connector pipe which takes away from what the chimney does. Single wall pipe allows the exhaust gasses to cool before entering chimney, so double wall stays hotter inside giving the chimney more heat to make it work.

The chimney is the engine that runs the stove. That is what makes any stove go. Heat is the fuel the chimney needs to make it work. A small fire has little heat to rise up the chimney creating the draft needed to get air into the stove. You need to know how much heat you’re putting into chimney with thermometer. This is easy with single wall pipe with magnetic thermometer measuring the surface temp of pipe. Surface temp is about 1/2 the actual inside flue gas temp. You need a probe type thermometer that measures the temp in the inner pipe. This must be hot enough to not cool below 250 all the way to the top. This determines how much air you give the fire and flue damper position to keep it clean and create the correct draft. This is why stove sizing is critical and you can’t simply build a smaller fire in a large stove when a stove is oversized for an area.


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## weaslemama (May 2, 2020)

Thank you so much, this is a really clear description of the dynamics involved and helps me understand the problem we’re having! 
Going to angle the connector pipe and also try adding some length to the chimney. 

Thanks again for everyone’s advice!


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## Isaac Carlson (May 2, 2020)

We used to have a horizontal section going into our chimney and always had draft problems.  We switched to an angled pipe and it got better.  Then we made the chimney 3 ft taller and it got even better.


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## coaly (May 2, 2020)

Most stoves were tested with 15 foot chimney. Manuals will many times require that as a minimum, but not because it is required for operation. Any stove tested and approved to UL testing criteria is called “Listed”.  Since they need to be installed “as tested” to comply with the listing, the manual gives that height. Some stoves work ok under that minimum, but as you can see how other factors decrease draft, you may need more height to create enough draft to compensate for other factors.

Elevation is another factor since the closer to sea level, the more air pressure pushing into the stove. The higher your elevation, the less air pressure, so you need more chimney height to make the pressure in stove even lower by creating more draft. This is why no one can tell you exactly where to set controls or what you need to do without lots more info. There are charts and tables to calculate the draft the vent system will create, then subtract the resistance for NET draft.


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## Isaac Carlson (May 2, 2020)

That's the scoop, coaly.  One thing that is lost in all of this is how much easier a non epa stove will burn under the same conditions.
They have less resistance all around, and will generally out burn an epa stove when conditions are poor, at least from my experience.


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## begreen (May 2, 2020)

Isaac Carlson said:


> That's the scoop, coaly.  One thing that is lost in all of this is how much easier a non epa stove will burn under the same conditions.
> They have less resistance all around, and will generally out burn an epa stove when conditions are poor, at least from my experience.


Often true, an older stove is not relying on draft to pull air up preheat channels to the air wash or secondaries. That said, some EPA stoves have more direct air paths and breathe easier than others.


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## nathan125 (May 5, 2020)

I love my Sweet Home Alpine. Best $60 I have ever spent and that included the pipe


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