Vermont Castings Defiant - smoke backing up, little control over intensity, other issues

[mloring]

Hello, I have a brand new VC Defiant stove installed in new construction and am having some issues which I suspect are peculiar to this stove (or at least to VC).

On a windy day there appears to be no way to keep the damper closed without a little smoke backing up into the house. I can't actually *see* any smoke but I can smell it, and I don't believe it's seeping through the structure from outside because the house is tight. I can get the stovetop up to 600+ with a nice bed of coals, add a log or two, close the damper, and soon smell smoke when the wind starts gusting. This continues while there is still wood in the stove to burn and wind blowing. We've had 60mph winds recently, but this happens with calmer winds, as well. The catalyst is clear and I see no other obstructions. Again, the stove is brand new and has been doing this since day 1. With the damper open I don't notice any smell of smoke.

This leads me to the second problem, which is really more concerning. Keeping the damper open, there is very little control over the intensity of the fire. With the damper open and the air control fully closed, the fire will rage to the point where the stove top will hit 800-900+ in a short amount of time. The chimney is tall - probably 30 feet to the cap - and it has a very strong draft. My wood has also been seasoned for a year, so quite dry. I can see the flap on the air inlet and it's fully closed.

These two issues combined make it very difficult to keep the house heated at night without a) smoke leaking into the house, or b) overfiring the stove. Anything more than a couple of small logs in the stove at a time with the damper open will make it dangerously hot.

This stove has an enormous fire box, and I imagine that it would self-destruct if I dared load it anywhere close to full.

Naturally I'd prefer not to get up every couple of hours at night to add a log or two at a time. This is our only source of heat, and the house is 2-story, about 2400 square feet.

I've been a VC owner for many years. I bought a small Aspen back in the 90s, which I still have in my shop, and which I love. Very fiddle-free. I've also been using a Resolute Acclaim for the past almost-20 years, which has it's own quirks (including smoke issues), but I've never felt that it might burn the house down if I put one too many logs in it.

I'd love to hear the experiences of other Defiant owners. This thing cost over $4000, so it's a real shame if there are inherent issues with it that are going to make it difficult to use.

 

[JeanneM]

I do not have a Defiant, but a new VC Dauntless. I do not have these problems but I am not using the stove to heat my house full time. From the members of this forum I have heard that stove top temps are not accurate and you should get a flue probe for more accurate temps and to be sure your stove is running how you want it to. I myself do not have a flue probe yet - and a more experienced member may be able to recommend one for you.

 

[Eman85]

I don't have a Defiant, I have an Encore which at the time it was made it was sold as a Defiant Encore. Your Defiant should be an airtight stove design so closing the primary air control should choke off air to the firebox whether the bypass is open or closed. I can burn mine without the bypass closed and the STT and flue temp will go wild unless I close down the primary air, but it is very controllable by closing the air. it sounds like you have an air leak or your primary control isn't working.

 

[mloring]

Thanks for the replies.

The interior stove pipe is double wall so the usual magnetic temperature gauges aren't very accurate. Maybe the stovetop isn't the best place to measure, either, though.

I don't think there are any air leaks. The gaskets I can see all look in new condition. The ash pan door is properly closed. There was a 1/4" gap at the flue adapter where it meets the stove (and it sounded like a whistle when there was a draft), but I sealed that.

Here's a picture of it burning with a small bed of coals, two split logs, damper open, air control fully closed (the glass is dirty so it's hard to see but he flames are fairly active). With my old Resolute, you'd turn down the air all the way and the logs would just smolder. I realize the Defiant has a thermostatically controlled air inlet (whereas the Resolute doesn't), but it appears to be fully closed when the control is at half position or less and the stove is hot.

Also a picture of the temp gauge I'm using. This is about 15 minutes after I added the logs to the stove. It started at around 500 degrees.

 

[mloring]

As a side note, it's just about impossible to heat our house on a cold day by burning the stove in the "optimum burn" zone of 300-500 degrees.

 

[Mreif]

Hello, I have a brand new VC Defiant stove installed in new construction and am having some issues which I suspect are peculiar to this stove (or at least to VC).

On a windy day there appears to be no way to keep the damper closed without a little smoke backing up into the house. I can't actually *see* any smoke but I can smell it, and I don't believe it's seeping through the structure from outside because the house is tight. I can get the stovetop up to 600+ with a nice bed of coals, add a log or two, close the damper, and soon smell smoke when the wind starts gusting. This continues while there is still wood in the stove to burn and wind blowing. We've had 60mph winds recently, but this happens with calmer winds, as well. The catalyst is clear and I see no other obstructions. Again, the stove is brand new and has been doing this since day 1. With the damper open I don't notice any smell of smoke.

This leads me to the second problem, which is really more concerning. Keeping the damper open, there is very little control over the intensity of the fire. With the damper open and the air control fully closed, the fire will rage to the point where the stove top will hit 800-900+ in a short amount of time. The chimney is tall - probably 30 feet to the cap - and it has a very strong draft. My wood has also been seasoned for a year, so quite dry. I can see the flap on the air inlet and it's fully closed.

These two issues combined make it very difficult to keep the house heated at night without a) smoke leaking into the house, or b) overfiring the stove. Anything more than a couple of small logs in the stove at a time with the damper open will make it dangerously hot.

This stove has an enormous fire box, and I imagine that it would self-destruct if I dared load it anywhere close to full.

Naturally I'd prefer not to get up every couple of hours at night to add a log or two at a time. This is our only source of heat, and the house is 2-story, about 2400 square feet.

I've been a VC owner for many years. I bought a small Aspen back in the 90s, which I still have in my shop, and which I love. Very fiddle-free. I've also been using a Resolute Acclaim for the past almost-20 years, which has it's own quirks (including smoke issues), but I've never felt that it might burn the house down if I put one too many logs in it.

I'd love to hear the experiences of other Defiant owners. This thing cost over $4000, so it's a real shame if there are inherent issues with it that are going to make it difficult to use.

I have an encore about 3 years old, same as yours just smaller. It was brand new when installed and I had trouble keeping it under control. It took awhile but I eventually figured out that the ashpan door was out of alignment and not closing tightly, something for the front doors. This was how it was when installed in my house. After re aligning both and making adjustments to the handles to make the doors close tighter the stove behaved much better. As far as your smoke smell make sure your flue Temps are high enough (600) internal before closing bypass.

 

[mloring]

I have an encore about 3 years old, same as yours just smaller. It was brand new when installed and I had trouble keeping it under control. It took awhile but I eventually figured out that the ashpan door was out of alignment and not closing tightly, something for the front doors. This was how it was when installed in my house. After re aligning both and making adjustments to the handles to make the doors close tighter the stove behaved much better. As far as your smoke smell make sure your flue Temps are high enough (600) internal before closing bypass.

I'm getting the feeling that burning it hotter than I normally would is going to be part of the solution here. If I get it up to 600-700 on the thermometer before I close the damper, it seems to help. Normally I would think that's getting on the hotter end of things but it appears to be a sweet spot with this stove.

 

[Eman85]

Many magnetic thermometers aren't very accurate, do you have an IR non contact gun to check it with? Can you use a mirror and physically look at your primary air shutter. You should be able to see if it's closing completely. No matter what it should be air tight and the primary air should smolder the fire down when closed, bypass open or closed.

 

[Mreif]

I'm getting the feeling that burning it hotter than I normally would is going to be part of the solution here. If I get it up to 600-700 on the thermometer before I close the damper, it seems to help. Normally I would think that's getting on the hotter end of things but it appears to be a sweet spot with this stove.

Where is your stt location, griddle?. I use mine on the stove in front of the the pipe. When mine was on the griddle I always got high readings. The fact that it's seems to be working better when it's in 600-700 range is because your flue Temps are higher also. You need a way to monitor flue Temps to help you know when to close bypass. I don't pay much attention to stt Temps as I do flue and cat Temps

 

[mloring]

Where is your stt location, griddle?. I use mine on the stove in front of the the pipe. When mine was on the griddle I always got high readings. The fact that it's seems to be working better when it's in 600-700 range is because your flue Temps are higher also. You need a way to monitor flue Temps to help you know when to close bypass. I don't pay much attention to stt Temps as I do flue and cat Temps

I also have the thermometer on the stovetop in front of the pipe (right behind the griddle).

 

[Kevin Weis]

I stop trusting any of those bi-metal thermometers as early on had two side by side brand new and they read 150 different from each other. Tossed them and got an IR gun and never looked back.

 

[mloring]

Many magnetic thermometers aren't very accurate, do you have an IR non contact gun to check it with? Can you use a mirror and physically look at your primary air shutter. You should be able to see if it's closing completely. No matter what it should be air tight and the primary air should smolder the fire down when closed, bypass open or closed.

I just read this tidbit in the manual:

"This wood heater has a manufacturer-set minimum low burn rate that must not be altered. It is against federal regulations to alter this setting or otherwise operate this wood heater in a manner inconsistent with operating instructions in this manual."

If I'm interpreting this correctly, I assume it means that the stove is not allowed to be choked off to the point of smoldering because that increases emissions beyond EPA limits. So we're left with a minimum burn rate that is too hot.

 

[GrumpyDad]

STT should be behind the griddle in front of the stove pipe. When you are starting up, STT should only be used to avoid overheating the top part of the stove. The rest of the stove will be cool to the touch on the sides for quite some time while the STT could be rather high if you have a blazing kindling fire and the subsequent smaller fire. STT isnt an absolute tool like a thermostat is to a furnace to some degree.
It's fine to look at it as a gage for curiosity sake. The best thing you can do for yourself is learn what the stove is putting out when you operate it in certain ways via a decent laser thermometer. Then, after awhile you wont even need to use one. You'll know fairly accurately if the stove is too hot, too cold, or just right when you walk up near it. You really will. If you run out and buy a million instruments/probes, you'll probably never learn and will be dependent on those things.

Sorry to hear about the smoke in your place. That's really odd with that much draft. Im sure you are sure there are no obstructions. Someone wiser than me may know why, and if your stove is blazing even on the lowest setting that seems to reaffirm you have a ton of draft...maybe too much. Why it would be kicking back smoke is odd.

Reading your posts it sounds like you benefit from a decent amount of heat, but what happens as the heat dies down when a load is being fully consumed?

The only thing I can think of that you might be doing is , not following the user manual for startup and operation. And maybe your wood moisture is too high. If you get a small bed of coals going and load it up with moist wood, you are going to get a TON of smoke and while you may have good draft , maybe it's just not enough to pull out that initial smoke. Then once the load catches, the draft is too high. So you may be dealing with two issues.

I struggled with a VC stove horribly initially. Ive learned everything can be resolved by just ensuring you have a great bed of coals before reloading. If you did a full load and let that burn down, you should have big chonky pieces of coals on top of 1-2" coals and putting your hand in there to shovel the coals from the front a bit should sear off your hand hairs . If I do this, I can pack the stove to the top and it runs good. Otherwise I have to only load it up a medium amount. Either way, you have to let a new load catch, and if you have a great bed of coals that new load will catch fairly quickly and you can immediately switch over to secondary and get great burns/heat/adjustability and some reliability.

A great bed of coals and making sure you catch your wood keeps the glass clean. I try to make sure I always see some flames when I turn down, and if I dont I turn it back up. Then eventually I see the wood to about mid way up has a nice orange glow to it, and occasional flames, and that's my sweet spot. Every hour or so I may adjust a notch or two up or down depending on how it looks in there. If it's cold yea, I have to turn it up some more and burn faster, but for the most part I can run at 450d STT behind the griddle for reference, can touch and hold my hand to the dbl wall stove pipe about 24" from the flue collar, 28 F outside, 70 inside, 650 sqft cathedral ceiling room attached to an older building that gets heat from this room or occasional kick on of the furnace.

Also the thermostatic control is questionable. I had a firebox full of flames and the stove was getting very hot. ON the lowest air control setting. I then move the air control back up to the highest setting and then to the lowest setting a couple of times, and that 'unstuck' it. When you look at the air intake and put it on the lowest setting, I would assume you see it move? I dont think they are meant to close all the way, mine doesnt. But when I put it on the lowest setting it wont be long until my firebox is completely void of anything orange in color. The best Ive gotten has been to have some well seasons oak burning for a few hours, taken it down to 3rd from lowest and still not blacken the glass.

It's all about those coals best I can tell. And wood quality which is required. My glass is fairly clear, to FULL clear. Sometimes I stack my wood and a piece falls in a manner that causes the top portions of my glass to turn black, but that eventually gets more clear or burns away all together.

 

[GrumpyDad]

I just read this tidbit in the manual:

"This wood heater has a manufacturer-set minimum low burn rate that must not be altered. It is against federal regulations to alter this setting or otherwise operate this wood heater in a manner inconsistent with operating instructions in this manual."

If I'm interpreting this correctly, I assume it means that the stove is not allowed to be choked off to the point of smoldering because that increases emissions beyond EPA limits. So we're left with a minimum burn rate that is too hot.

If I put my air control to the lowest setting with a box full of wood that has caught and a GREAT bed of coals, I can choke down to the point that I see no more flames and my glass goes black. I run with just above the minimum draft requirements.

 

[mloring]

STT should be behind the griddle in front of the stove pipe. When you are starting up, STT should only be used to avoid overheating the top part of the stove. The rest of the stove will be cool to the touch on the sides for quite some time while the STT could be rather high if you have a blazing kindling fire and the subsequent smaller fire. STT isnt an absolute tool like a thermostat is to a furnace to some degree.
It's fine to look at it as a gage for curiosity sake. The best thing you can do for yourself is learn what the stove is putting out when you operate it in certain ways via a decent laser thermometer. Then, after awhile you wont even need to use one. You'll know fairly accurately if the stove is too hot, too cold, or just right when you walk up near it. You really will. If you run out and buy a million instruments/probes, you'll probably never learn and will be dependent on those things.

Yep, the gauge is right where you describe. It really seems as though it will register around 700 degrees (whether accurate or not) before I can close the damper with wood in the stove on a windy day, without smoke backing up. Less than that is OK on a calm day.

Sorry to hear about the smoke in your place. That's really odd with that much draft. Im sure you are sure there are no obstructions. Someone wiser than me may know why, and if your stove is blazing even on the lowest setting that seems to reaffirm you have a ton of draft...maybe too much. Why it would be kicking back smoke is odd.

Definitely no obstructions. Everything is brand new and it's a straight shot from the stove to the chimney cap. When the damper is closed, I guess the path for smoke to exit the stove is obviously more restricted and convoluted just by design. Not a lot I can do about that, but I suspect that's why a gust of wind has an easier time pushing smoke back into the house under those conditions.

Reading your posts it sounds like you benefit from a decent amount of heat, but what happens as the heat dies down when a load is being fully consumed?

Once the load is consumed the smoke problem goes away.

The only thing I can think of that you might be doing is , not following the user manual for startup and operation. And maybe your wood moisture is too high. If you get a small bed of coals going and load it up with moist wood, you are going to get a TON of smoke and while you may have good draft , maybe it's just not enough to pull out that initial smoke. Then once the load catches, the draft is too high. So you may be dealing with two issues.

I struggled with a VC stove horribly initially. Ive learned everything can be resolved by just ensuring you have a great bed of coals before reloading. If you did a full load and let that burn down, you should have big chonky pieces of coals on top of 1-2" coals and putting your hand in there to shovel the coals from the front a bit should sear off your hand hairs . If I do this, I can pack the stove to the top and it runs good. Otherwise I have to only load it up a medium amount. Either way, you have to let a new load catch, and if you have a great bed of coals that new load will catch fairly quickly and you can immediately switch over to secondary and get great burns/heat/adjustability and some reliability.

I think that's good advice. A nice bed of coals and a hot STT seem to mitigate the problem of smoke in the house. It just takes a lot more planning than my previous stove, and without a backup source of heat it can be a pain if I come home late at night and just want to sleep.

A great bed of coals and making sure you catch your wood keeps the glass clean. I try to make sure I always see some flames when I turn down, and if I dont I turn it back up. Then eventually I see the wood to about mid way up has a nice orange glow to it, and occasional flames, and that's my sweet spot. Every hour or so I may adjust a notch or two up or down depending on how it looks in there. If it's cold yea, I have to turn it up some more and burn faster, but for the most part I can run at 450d STT behind the griddle for reference, can touch and hold my hand to the dbl wall stove pipe about 24" from the flue collar, 28 F outside, 70 inside, 650 sqft cathedral ceiling room attached to an older building that gets heat from this room or occasional kick on of the furnace.

I'm definitely having to run it hotter to keep my place warm. We've been in the high 20s/low 30s for much of the past month. I can briefly touch the double wall pipe two feet up but it's quite hot. And the STT is running much hotter than 450.

Also the thermostatic control is questionable. I had a firebox full of flames and the stove was getting very hot. ON the lowest air control setting. I then move the air control back up to the highest setting and then to the lowest setting a couple of times, and that 'unstuck' it. When you look at the air intake and put it on the lowest setting, I would assume you see it move? I dont think they are meant to close all the way, mine doesnt. But when I put it on the lowest setting it wont be long until my firebox is completely void of anything orange in color. The best Ive gotten has been to have some well seasons oak burning for a few hours, taken it down to 3rd from lowest and still not blacken the glass.

It's all about those coals best I can tell. And wood quality which is required. My glass is fairly clear, to FULL clear. Sometimes I stack my wood and a piece falls in a manner that causes the top portions of my glass to turn black, but that eventually gets more clear or burns away all together.

The flap on the air intake moves like I imagine it should. As the stove gets warmer the thermostatic control closes it more relative to the setting of the lever. The Aspen I have works the same way. If that stove is really hot you almost can't open the inlet, even with the lever full "open."

I'm burning mostly Doug fir and pine, which was mostly from dead trees cut in the spring and seasoned all summer in the direct 100 degree heat that we had. It seems pretty dry and burns easily. Maybe it's too dry. I put a couple of splits in last night on top of a bed of coals, damper open and air control all the way "closed," and within 30 minutes the stove top temp was peaking the gauge at 900. So while it appears I have the smoke situation figured out, I'm still concerned about the apparent lack of control over firing. Closing the damper is the only way to bring it under control. I won't leave the house or go to sleep without the damper closed. I wonder if this isn't by design, though, given the aforementioned EPA issues. It reminds me of my VW diesel - one of the batch subject to the emissions scandal some years back. That car will throttle the output of the engine JUST to avoid producing smoke at the exhaust. Any normal diesel engine, or gas engine for that matter, would at least make an effort when you step on it, but this one's primary objective is regulating smoke output so it can comply with particulate regulations. If it didn't get 50mpg I would ditch it. Hah!

 

[GrumpyDad]

Yep, the gauge is right where you describe. It really seems as though it will register around 700 degrees (whether accurate or not) before I can close the damper with wood in the stove on a windy day, without smoke backing up. Less than that is OK on a calm day.

Definitely no obstructions. Everything is brand new and it's a straight shot from the stove to the chimney cap. When the damper is closed, I guess the path for smoke to exit the stove is obviously more restricted and convoluted just by design. Not a lot I can do about that, but I suspect that's why a gust of wind has an easier time pushing smoke back into the house under those conditions.

Once the load is consumed the smoke problem goes away.

I think that's good advice. A nice bed of coals and a hot STT seem to mitigate the problem of smoke in the house. It just takes a lot more planning than my previous stove, and without a backup source of heat it can be a pain if I come home late at night and just want to sleep.

I'm definitely having to run it hotter to keep my place warm. We've been in the high 20s/low 30s for much of the past month. I can briefly touch the double wall pipe two feet up but it's quite hot. And the STT is running much hotter than 450.

The flap on the air intake moves like I imagine it should. As the stove gets warmer the thermostatic control closes it more relative to the setting of the lever. The Aspen I have works the same way. If that stove is really hot you almost can't open the inlet, even with the lever full "open."

I'm burning mostly Doug fir and pine, which was mostly from dead trees cut in the spring and seasoned all summer in the direct 100 degree heat that we had. It seems pretty dry and burns easily. Maybe it's too dry. I put a couple of splits in last night on top of a bed of coals, damper open and air control all the way "closed," and within 30 minutes the stove top temp was peaking the gauge at 900. So while it appears I have the smoke situation figured out, I'm still concerned about the apparent lack of control over firing. Closing the damper is the only way to bring it under control. I won't leave the house or go to sleep without the damper closed. I wonder if this isn't by design, though, given the aforementioned EPA issues. It reminds me of my VW diesel - one of the batch subject to the emissions scandal some years back. That car will throttle the output of the engine JUST to avoid producing smoke at the exhaust. Any normal diesel engine, or gas engine for that matter, would at least make an effort when you step on it, but this one's primary objective is regulating smoke output so it can comply with particulate regulations. If it didn't get 50mpg I would ditch it. Hah!

Next time you have smoke coming back in, open a window or door near by to see if that helps. If it does you may need an outside air kit.