Whether to install a VC Vigilant, and how else to reduce puffing

[Jprinter]

Hi,

We’ve had a problem with our wood stove back puffing in our house, and are wondering if we ought to consider swapping it out with another stove (along with other, suggested changes). Some background first…

I’ve currently got a Lennox wood stove (model CI1000HT) in the bottom floor of a bilevel house (roughly 2,500 square feet). Our house was built in the late 1970s and, like other houses in our neighborhood, it is a tightly sealed house — too tight, in fact, with little airflow. That, combined with the stove’s location on the bottom floor, no intake ventilation for the stove, and a single-walled stove pipe (which gets quite cold during the winter, and apparently wasn’t fitted at the right angle) contributes to the back puffing.

Yes, we do heat the stove pipe and open windows and doors before starting an initial fire. It helps, but our house still gets smokey even will all of these measures. And yes, we’ve had the chimney cleaned recently.

The chimney cleaner suggested we redo the pipe — both using double walled pipe, and refitting how the stove is connected to the pipe, and is shaped at the right angle from the stove to the wall. (He also suggested installing a draw collar to the chimney pipe.) And some have suggested that after all of that we might also want to consider swapping out the Lennox with another wood stove that’s breaths better.

Anyway, I just got a free Vermont Castings Vigilant 1977 that’s in good shape. I’ve cleaned it and, as far as I can tell, nothing seems broken. I’ve done some research on the stove, and know it’s an older, well-built, sturdy stove — though it was "hi-tech" (for its time) by using the damper for secondary burns. I can see how it might “breath” better than the Lennox (i.e., through the temperature door in the back, and air valve). But I know it’s less efficient than more modern woods stoves, and that it lacks certain environmental features that found in modern stoves.

Overall, would others suggest or discourage me from replacing the Lennox and with this VC Vigilant 1977?

Our main concern is avoiding back puffing for any stove. So, I’m wondering if this VC Vigilant 1977 would be better a better fit for our house, as far as being able to “breath” better — and less inclined to smoke us out compared to the Lennox?

If I do install this stove (even as a temporary solution) I could install a double-walled (and better fitting) chimney pipe, and redo all the stove gaskets. Beyond that, we’d crack a window to prevent back-puffing — and I’d welcome any other ideas for additional mitigation. But again, I’m first trying to determine if it’s advisable to install this VC Vigilant 1977 in the first place.

Thanks!

 

[begreen]

The Vigilant, if in good working condition, will breath easier, but will be less efficient than the Lennox. However, backpuffing may still occur because changing the stove may be treating the symptom and not cause, which I suspect is negative pressure.

If you can tell us more about the house and include some pictures of the current stove setup (including stove pipe) and the chimney outside, we may be able to offer suggestions to address the negative pressure. There are several possible causes. Some are easier than others to address.
Here is a good site with a series on chimneys that explains causes of negative pressure:

A non-commercial service in support of responsible home heating with wood - All About Chimneys

The Wood Heat Organization was formed to support the public in the responsible use of wood energy in the home. We fulfill our mandate by providing reliable information, by conducting research into wood heating-related issues and by representing the public interest in discussions of policies that...

woodheat.org

 

[John Lehet]

I lived with, heated 100% with a 1970s vigilant for a couple of years in the early 80s. Perhaps my view isn't worth much, because I was very young and renting, and the whole group house didn't know what we were doing. And wood probably not dry enough at all. And those were cold winters in Vermont. I remember our wood was stacked outdoors in rows, and we had to dig it out of the snow. I don't remember the details of when we stacked the wood, but it certainly would not pass my standards now, I'm sure!

Compared to almost any stove I've had since, the experience was really bad. We were cold, pipes froze, chimney full of creosote. Like I say, if I did it now with my dry wood and understanding what to do, it might be better. It was really cold, sitting right in front of the stove.

Modern stoves are amazing -- more heat, less creosote, less fiddling, no (or minimal) chimney fire danger. And you'll burn half the wood with a modern stove.

 

[Jprinter]

The Vigilant, if in good working condition, will breath easier, but will be less efficient than the Lennox. However, backpuffing may still occur because changing the stove may be treating the symptom and not cause, which I suspect is negative pressure.

If you can tell us more about the house and include some pictures of the current stove setup (including stove pipe) and the chimney outside, we may be able to offer suggestions to address the negative pressure. There are several possible causes. Some are easier than others to address.
Here is a good site with a series on chimneys that explains causes of negative pressure:

A non-commercial service in support of responsible home heating with wood - All About Chimneys

The Wood Heat Organization was formed to support the public in the responsible use of wood energy in the home. We fulfill our mandate by providing reliable information, by conducting research into wood heating-related issues and by representing the public interest in discussions of policies that...

woodheat.org

Thank you so much for all of this -- it's terrific input, and I greatly appreciate all of your assistance!

I'm attaching some pics of the current set up of the Lennox stove, include the placard for that stove. (I didn't install it; it came with the house.) I didn't manage to take pics of the chimney outside because it was too overcast to get a decent photo. However, I've had several people look at the chimney (chimney sweeps, a few local experts on wood stoves), and they've all said it's the right height. No one believes the chimney height and build have contributed to the back puffing issue. (BTW, the plat covering in my pic is where I had to replace the glass for the door.)

Here are the the chimney pipe dimensions, in case that's helpful:

-The first chimney pipe measures 40" from the stove to where the 45 degree bend joint begins;

-The next section of chimney pipe measures 25" to where the next 45 degree bend joint begins;

-Then there's a 6" section of chimney pipe;

-Finally, there's a 3" cap that connects the last section of chimney pipe to the ceiling -- or where the internal chimney piping begins;

I take your point when you said:

backpuffing may still occur because changing the stove may be treating the symptom and not cause, which I suspect is negative pressure.

I'm sure you're right; I think the problems we face are mostly because of the tightness of the house and negative pressure. Our neighbors (whose home are similar to ours) keep a window by their stove open whenever they've got a fire burning. They also warm their chimney pipe with a torch or heat gun.

I confess I dislike the Lennox (which I find fussy and unpleasant to use for various reasons), and I do like the look and feel of a VC stove. But I do understand it is less efficient than a modern stove though, again, I'm wondering if it might work (even as a stop gap) as a stove that might at least breathe better and help cut down on the back puffing. Or if it's just not worth it.

Thanks so much, again.

 

[EatenByLimestone]

What altitude are you at?

 

[EbS-P]

Basement install introduce more complexity. Im guessing there is a bit of a low pressure zone down there. How does the stove light on a cold start? Air sealing the upper floors can help. I’m guessing the house is not as tight as you think it is. (I could be wrong)

 

[Jprinter]

What altitude are you at?

Almost 5k feet at our location.

 

[begreen]

The house design, chimney location and height can affect draft. There are other chimney links on the WoodHeat website that are worth reading. At 5,000 ft, the chimney will need additional height. What is the current flue system height from stove top to the chimney cap? Is the chimney chased (enclosed) through the upper level? Is the offset in the room the only offset or does the chimney pipe also have an offset?

Negative pressure can be caused by leakage on the upper floor. This leakage can be through bath and kitchen fan vents and exacerbated when these fans are in operation. Sometimes leaky attic doors, windows, etc. can also cause a pressure drop on the lower floor.

The issue with any stove that has weak or failing draft is draft reversal as the fire dies down in the later coaling stage. At that point, carbon monoxide can enter the room from the coals. That's a very bad thing and may still happen with the Vigilant. A draw collar will help, but what if it fails or there is a power outage? In the least, the room needs a good, CO monitor in addition to a smoke detector.

Hopefully it's light enough now to take a picture of the outside chimney and post it.

 

[EatenByLimestone]

Can you give us more information about the chimney that we can’t see? Length and diameter.

 

[Jprinter]

Basement install introduce more complexity. Im guessing there is a bit of a low pressure zone down there. How does the stove light on a cold start? Air sealing the upper floors can help. I’m guessing the house is not as tight as you think it is. (I could be wrong)

It does not light well on a cold start. Our neighbors often heat their chimney pipes with a torch or heat gun to help start things up, and ensure the smoke flows through the chimney properly (as well as have a downstair window and/or door open when starting up).

As for the house being tight, our contractor and neighbors have all remarked at how unusually tight our houses are -- all of which were constructed during the late 1970s/early 1980s, mostly be the same builder. FWIW...

 

[Jprinter]

The house design, chimney location and height can affect draft. There are other chimney links on the WoodHeat website that are worth reading. At 5,000 ft, the chimney will need additional height. What is the current flue system height from stove top to the chimney cap? Is the chimney chased (enclosed) through the upper level? Is the offset in the room the only offset or does the chimney pipe also have an offset?

Negative pressure can be caused by leakage on the upper floor. This leakage can be through bath and kitchen fan vents and exacerbated when these fans are in operation. Sometimes leaky attic doors, windows, etc. can also cause a pressure drop on the lower floor.

The issue with any stove that has weak or failing draft is draft reversal as the fire dies down in the later coaling stage. At that point, carbon monoxide can enter the room from the coals. That's a very bad thing and may still happen with the Vigilant. A draw collar will help, but what if it fails or there is a power outage? In the least, the room needs a good, CO monitor in addition to a smoke detector.

Hopefully it's light enough now to take a picture of the outside chimney and post it.

Here a the pics you requested of the chimney. I'm just relaying what several people have said after inspecting the chimney (contractors, those who install and repair wood stove, and our chimney sweeP: they feel it's at an appropriate height, it's has the right cap, and is in good condition.

BTW, our bathroom fans are very far from the stove, and aren't very strong at all. We don't have an attic doors, and the windows are in good shape.

I hear you about CO monitors. We have them installed, but need to get additional monitors set lower down. Some people in our town suggested we get the energy company to come by to do a CO2 inspection and air flow analysis. So, all of these considerations are definitely top of mind. Thanks so much!

 

[EatenByLimestone]

You have a mostly interior chimney. Cold starts shouldn’t be an issue. Do you crack a window by the stove when lighting? How long has your wood been drying?

 

[begreen]

I see about 5' exterior chimney and about 6" with an offset, interior stovepipe. How much chimney pipe length do we not see?

If the total is 14', it's not enough for this altitude unless the stove is a very easy breather. At 5,000 ft. here is what's needed for the average stove.

 

[Jprinter]

You have a mostly interior chimney. Cold starts shouldn’t be an issue. Do you crack a window by the stove when lighting? How long has your wood been drying?

Yes, we crack a nearby window, and sometimes even a door, when lighting. We get our wood from a local dealer who provides the best wood in the valley. It’s as seasoned as we can get.

 

[Jprinter]

I see about 5' exterior chimney and about 6" with an offset, interior stovepipe. How much chimney pipe length do we not see?

If the total is 14', it's not enough for this altitude unless the stove is a very easy breather. At 5,000 ft. here is what's needed for the average stove.

View attachment 340768

Thanks for this. So, we’re just trying under 5K ‘ elevation, FWIW. Your analysis might be correct, but the chimney is certainly taller than what our neighbors have, and we’ve had several people here inspect the chimney— and all of them have said its height is more than adequate. Again, I’m just relaying what they’ve told me. I’m happy to get yet another opinion, however. Thanks you!

 

[EatenByLimestone]

How dry is the wood though? Wet wood can make starting and running a fire very frustrating. Pick up a moisture meter at Home Depot, split a regular sized split in half, and test with the grain in the center.

 

[kborndale]

Yes, we crack a nearby window, and sometimes even a door, when lighting. We get our wood from a local dealer who provides the best wood in the valley. It’s as seasoned as we can get.

Buying wood from a dealer means there is a very small chance it is actually seasoned and ready to burn. You have to get a year ahead on your wood and you will have much better results.

 

[EatenByLimestone]

I think the wood is probably the issue here, but OP may be burning a quick seasoning species.

A cheapie meter will either confirm or tell us we have to keep looking for the answer. $30 to help solve an issue vs the cost of a new stove or chimney seems like a no brainer.

 

[WNCStove]

Don’t dampen it down as much. Also, don’t buy a Vermont castings anything ever again 😀

 

[Jprinter]

Thank you, again, for everyone's helpful input. I feel like many people have provided lots of useful information, and I'm trying to put it all together to figure out a solution -- or a set of things I should tackle. To recap, here's what I understand...

• @begreen said, "The Vigilant, if in good working condition, will breath easier, but will be less efficient than the Lennox. However, backpuffing may still occur because changing the stove may be treating the symptom and not cause, which I suspect is negative pressure."
• @begreen and @EatenByLimestone asked for more info and pics of the chimney pipe inside the house, and the chimney outside the house. I provided those pics, and...
• ...in response to my pics, @begreen said, "If the total [chimney height] is 14', it's not enough for this altitude unless the stove is a very easy breather." Well, the current Lennox stove we have certainly doesn't feel like a strong breather. As I said, we've been advised to have a window open -- at least during start-up -- but are inclined to keep one up just in case the fire smolders, to prevent against negative pressure and back puffing.
• I take the points raised by @kborndale and @EatenByLimestone regarding damp and seasoned wood. While I expect that could be a contributing factor, I don't think it wholly explains why we've had so much back puffing with our stove and set-up. After all, our neighbors buy their wood from the same source (some even use less seasoned wood), and don't face the same problems.
• Clearly @John Lehet and @WNCStove are no fans of Vermont Casting stoves (especially the Vigilant 1977), and I appreciate that and understand how they're less efficient than modern stoves.

Here are the steps forward, and remaining questions...

• I'll gladly pick up a moisture meter, and will do more to cover our wood and reduce moisture;
• As I said, I'm surprised by @begreen's remarks re: prescribed chimney height, given that contractors, chimney sweeps, and wood stove experts all felt it was an appropriate height. I'm wondering if there's someone else -- someone category of chimney / stove expert -- who we can hire to check it out, and even add onto the chimney if that would help. Any suggestions?
• Again, I'm wondering if the free, clean Vigilant I have is worth installing, even as a temporary measure -- considering it might breath better, and therefore reduce the back puffing we've experienced. What are your thoughts?

Thank you everyone!

 

[begreen]

• I'll gladly pick up a moisture meter, and will do more to cover our wood and reduce moisture;
• As I said, I'm surprised by @begreen's remarks re: prescribed chimney height, given that contractors, chimney sweeps, and wood stove experts all felt it was an appropriate height. I'm wondering if there's someone else -- someone category of chimney / stove expert -- who we can hire to check it out, and even add onto the chimney if that would help. Any suggestions?
• Again, I'm wondering if the free, clean Vigilant I have is worth installing, even as a temporary measure -- considering it might breath better, and therefore reduce the back puffing we've experienced. What are your thoughts?

Some of this has already been answered. A lot of stove installers are just doing a job and not necessarily up to code. Some never read the manual before installing. The altitude adjustment is not new. It's in the current VC manuals. It's also recommended in several other stove manuals. The old Vigilant is definitely an easy breather. It has a simple, non-restrictive secondary burn. That said, it will not make up for negative pressure in the room so back-puffing is still a possibility. Increasing draft strength can compensate.

Learn how to use the moisture meter properly. Many people, including some wood sellers use it incorrectly.

It won't hurt to try the Vigilant, but make sure it is in proper working order and has no cracks or leaks along seams. Pay attention to clearances and hearth requirements per the manual. Personally, I would temporarily extend the chimney 3-4' using some cheap duct pipe on a calm day and see how things work with the present stove. If the improvement is significant, make it permanent with proper chimney pipe.

 

[coal and wood man]

I have a Vigilant and a Resolute. Both pre-CAT. The Vigilant likes to burn hot. Once the chimney pipe gets hot it should just suck that smoke up but it may take a time to get there. VC does recommend at least a 16' chimney height in their manual at least for their pre 1990 stoves. Do you make your fires bottom up or top down? I find top down with 1 or 2 large pieces in the bottom then paper and very dry kindling gets the pipe hot in no time. Even though I use fire starters every now and then I find they do not get the fire going soon enough. And lastly dry wood is a must. If you do not have a moisture meter you can cheat and use an ohmmeter. I like to see 3M or higher ohms. There is a good post on this site about using an ohmmeter too.