My canadian wood stove with little draft.

[oldbeaver]

Hello guys, this is Jose from Chile. Love my wood stove, but this winter it is producing too much smoke that gets in the house if I so not keep the door closed.

Stove front picture.
It is rather big (70 cm internal wideness). Has a double combustion chamber, as it has a flat iron sheet inside, that divides the stove horizontaly. This sheet is 30 cm deep x 70 cm wide, leaving a 20 x 70 cm open. This way, after burning in lower chamber go up to a second stage combustion chamber where they continue to burn. After that they go up to the exhaust.

The stove has a kind of serial number and a plate, but I do not know the make of the stove. It says tested by WH 296889 ( Warnock Hersey Haugh), 1994. Made in Canada. Plate:

The air intake is from below the stove, that can be regulated with this golden knob in the picture.
Air intake picture:

Problem is that I cannot see how the air gets into the combustion chamber to check if there is something cloggind the air ducts.

Maybe someone in the forum may have more knowledge and give me a hand at the distance. I would be very grateful. There are many people with wood stoves but they are all local made, and different.

Even helping me identifying the make and model would be very helpful.

Best,

Oldbeaver

 

[brenndatomu]

Is your stove pipe, chimney, or cap plugged? (even just partially?)
That is the most likely scenario...the chimney makes the draft, not the stove.

 

[stoveliker]

I agree with the above; if smoke comes out the door, it means it can't go up the flue. That's not an intake issue but an exhaust issue (blockage).

When is the last time the flue was cleaned?
How much wood have you burned since then?
How dry is your wood? (wetter wood can create more deposits in the chimney). You can measure the moisture content with a moisture meters. They are about $30 in the US. (E.g. I have a General Tools mmd4e - but most any in that range would work.)

 

[oldbeaver]

Is your stove pipe, chimney, or cap plugged? (even just partially?)
That is the most likely scenario...the chimney makes the draft, not the stove.

Hello Brenda, thank you for coming. Well, to be honest, I don't understand yr question precisely, due to my limited English. Anyway, if I got that right: my stove has a pipe attached to the exhaust that goes strait up for about 5 meters, through the ceiling and to the open air. Over the roof it has a special double isolation cover to keep it warm, so the gases go up and out. No chimney in my case.

I think I will attach somehow my vacuum cleaner to the air intake of the stove, (which is very difficult to access and I bet will hurt my back, by the way), and will make it work in reverse, that is, blowing instead of aspiring, to make the air blow out the ash that may be inside the duct, wherever it may be. Kind of "bright force" method we may call it ... hahaha.

At the same time, I will clean the pipe, which I checked from above on the roof. It looks open but with lots of coal dust (I don't the name in English). And, I will replace the iron sheet in the middle of the stove, because it is seriously rusted and twisted.

Well, yr response gave me a push to remember I did all of that a couple of years ago. And worked. I will let you know how it goes.

Hope you are doing well. Have a nice evening and again, thank you.

Best,

Jose (oldbeaver)

PS: where do you live, by the way?

 

[oldbeaver]

I agree with the above; if smoke comes out the door, it means it can't go up the flue. That's not an intake issue but an exhaust issue (blockage).

When is the last time the flue was cleaned?
How much wood have you burned since then?
How dry is your wood? (wetter wood can create more deposits in the chimney). You can measure the moisture content with a moisture meters. They are about $30 in the US. (E.g. I have a General Tools mmd4e - but most any in that range would work.)

Good point. Yes, as you say, it may be an exhaust issue. Two years at least. I will clean it.

Thank you.

 

[stoveliker]

Don't blow on the air intake unless you are absorbed sure that the stove is airtight.. otherwise you will get a mess of ashes in your home.

Check if there is soot ('coal dust' etc) on that plate and in the pathway for the exhaust gases before they reach the pipe.

 

[begreen]

Good point. Yes, as you say, it may be an exhaust issue. Two years at least. I will clean it.

Thank you.

That most likely is the issue. If the chimney cap has a screen, also clean that well. It is a common blockage point.

 

[oldbeaver]

Well, I did my duties and cleaned the exhaust pipe (the flue) from top to bottom. Some dirt came down, but not much. About 1 liter in volume I may say.

I tested the stove after that and it behaves the same, smoke do not go up as it should, and a lot of it comes into the room. From this result I deduct that begreen hyphotesis didn't solve the problem. There is something clogging the air intake duct. If I can get a manual of my stove, I may figure out how to clean it. But the manual I got (attached), is about smaller models. It doesn't mention the iron sheet that exists inside the combustion chamber. In this manual the biggest stove model is the FW 2700, which has a firebox floor area of 577 x 349 mm, while mine has one of 700 x 410 mm area.

In the meantime, I asked someone to make a new sheet. The new sheet is 2mm thick, 30 cm wide and 70cm long. I need to put it inside in position, something not easy. To get the old one out, I had to make a lot of movements. Finally I got it out. Then the new one should come in.

But I don't think this new plate will increment the flow of air, rather the opposite. The old one was twisted, this one will close the chamber better.

Maybe someone of the forum members may tell me how does the air intake flow enters the combustion chamber, I mean where are the ducts that allow this. By the way, the stove has another air intake on the back, probably to attach a blower.

Well, in relation to attach a blower to the air intake from the bottom, below the stove, I cleaned all the ash as well as I could, and very little is in there. Maybe some between the floor refractary bricks. So I hope no ash spilling will occur.

What I need to learn is how does the air intake comes into the combustion chamber. Where are the ducts. I don't see any coming into it.
The manual does not say a world about this. No about the sheet also. There is no picture either.

Any ideas folks?

Best,

Oldbeaver.

(Excuse my poor English).

 

[stoveliker]

Are you sure there is no obstruction in the stove from firebox to the flue?

 

[begreen]

Can we assume that the cleaning was done all the way up to the cap and screen? Obstruction of the air intake is very rare, but I suppose a fat mouse could have built a nest in there. One other thing to check is to make sure that the air control arm is still linked to the air control valve.

 

[oldbeaver]

Dear stoveliker,

Completely sure. The flue is a 6" stainless steel pipe, that goes strait up throu the ceiling out to the roof. I went to the roof and pushed a almost 6" tube, surrounded with cloth, attached to the pool stick (5 meters long) from the bottom down to the stove, several times. It was taken out by a helper at the stove. Only about 1 liter of carbon dust litter come down to the stove. You can see freely across the flue in both senses.

 

[bholler]

What is the outside temperature when you are having issues with smoke in the house?

 

[oldbeaver]

Can we assume that the cleaning was done all the way up to the cap and screen? Obstruction of the air intake is very rare, but I suppose a fat mouse could have built a nest in there. One other thing to check is to make sure that the air control arm is still linked to the air control valve.

I suppose the cup is the top closing of the flue. It is a kind of cup called "four winds cup" (picture attached). I had to take it out before doing the task, of course.

I am not sure what is the screen. Please send a description or a picture.

Thanks

 

[oldbeaver]

Some more pictures of my stove....

 

[begreen]

Was the flue pipe brushed or blown out with the leaf blower?

Note that single-wall is not advised for more than 8 ft of stovepipe due to excessive cooling of the flue gases. It also needs 18" clearance from all combustibles. It looks closer than that at least up at the top.

Also, the side clearance appears to be unsafe, not to code, or following the manual requirements.

 

[stoveliker]

Dear stoveliker,

Completely sure. The flue is a 6" stainless steel pipe, that goes strait up throu the ceiling out to the roof. I went to the roof and pushed a almost 6" tube, surrounded with cloth, attached to the pool stick (5 meters long) from the bottom down to the stove, several times. It was taken out by a helper at the stove. Only about 1 liter of carbon dust litter come down to the stove. You can see freely across the flue in both senses.

Yes. But you describe the flue, not the path below the stove collar.

Although getting the soot out from the firebox suggests the path is open.

I still believe that it's an exhaust issue, because if the door opens and there should be air rushing in regardless of whether there is an intake blockage or not.

But I'm stumped.

Some pics from inside the stove.may help.

 

[oldbeaver]

Was the flue pipe brushed or blown out with the leaf blower?

Note that single-wall is not advised for more than 8 ft of stovepipe due to excessive cooling of the flue gases. It also needs 18" clearance from all combustibles. It looks closer than that at least up at the top.

Also, the side clearance appears to be unsafe, not to code, or following the manual requirements.

The pipe was brushed, not blowed. Not with a brush but with a rag. I will make a brush soon.
The flue has a double pipe (isolated) only over the roof. But it has worked well this way for about 10 years, without a problem.
The clearence to combustibles is a good point. Never had a problem, maybe we use the stove at half its power, because the fuelwood available is small, made for smaller stoves. We just make a fire in the middle of the stove.

Thank you for the comments.

 

[oldbeaver]

Yes. But you describe the flue, not the path below the stove collar.

Although getting the soot out from the firebox suggests the path is open.

I still believe that it's an exhaust issue, because if the door opens and there should be air rushing in regardless of whether there is an intake blockage or not.

But I'm stumped.

Some pics from inside the stove.may help.

stoveliker, well, I atached the blower to the airflow inlet and discovered how and where the air gets into the stove. Almost no dust or ash came into the stove. The ducts are very well designed and located to avoid clogging and bring air very well spread.

I am attaching 2 pictures of the inside of the stove, looking up. Anyway, as the pipe is straight, if you take out the cap, you can see perfectly well the daylight. It is completely open.

Today it was a warm day, we didn't light the stove.

Thank you for your help.

 

[stoveliker]

Ah. I got confused by the earlier mention of a plate, which I assumed to be a baffle plate (above which blockages.can exist). But there is no such thing here.

 

[oldbeaver]

Ah. I got confused by the earlier mention of a plate, which I assumed to be a baffle plate (above which blockages.can exist). But there is no such thing here.

Well, seems to be that very few stoves has this plate or sheet. It covers about 2/3 of the surface of the burning chamber, leaving a window at the front. When the stove is burning well, you can see the burning gases turn to the front to pass through this window, not directly to the flue. From what I recall, this increases the efficiency of the combustion and reduce the emission of pollution gases. I don't know if we can call that a kind of "catalytic" process. Here they explain the issue: https://www.brighthubengineering.co...secondary-combustion-systems-for-wood-stoves/
I am attaching an image with a schematic design of the process, that I found in another site, which I cannot find. I will if you need it.
As well as in the diagram, my stove has an airflow entrance from the back.

I tested the stove with paper, and the smoke is severe. It was warm yesterday, so I have to test it again in a cold day.

Best

 

[begreen]

Most stoves have a baffle, including the one shown in the diagram. Baffles may be steel, stainless, firebrick, ceramic board, etc. They lengthen the smoke path for more complete combustion of the wood gases before they head up the flue.



What is this bracket for in the stove? It looks like a baffle support, but the picture doesn't show the whole upper firebox. Is there a matching one on the left side of the firebox?

This is an old and basic stove. It looks like it might be a Haugh/Century S244 and is not meant to operate like a fireplace with the door open except on loading. If there is smoke spillage the issue may be chimney location in relation to the roof and nearby structures, This might be worse due to atmospherics and outside temperature or wind. What altitude is it at?

 

[oldbeaver]

Most stoves have a baffle, including the one shown in the diagram. Baffles may be steel, stainless, firebrick, ceramic board, etc. They lengthen the smoke path for more complete combustion of the wood gases before they head up the flue.

View attachment 294966

What is this bracket for in the stove? It looks like a baffle support, but the picture doesn't show the whole upper firebox. Is there a matching one on the left side of the firebox?

View attachment 294967

This is an old and basic stove. It is not meant to operate with the door open except on loading. If there is smoke spillage the issue may be chimney location in relation to the roof and nearby structures, This might be worse due to atmospherics. What altitude is it at?

Yes, it is a baffle plate support. It has one. The first picture has the baffle in position, so you cannot see the flue.
Altitude here is 150 m over sea level.

 

[begreen]

Thanks for the clarification. 150 meters is not too high. Would it be possible to show the chimney top and the roof location of the chimney?

 

[stoveliker]

Yes. I understand. I was thinking you may have crud blocking (exhausting) air flow on top of the baffle, but you can take it out and look into the pipe up to the cap, I think. That's where my confusion came from.
But that's not it.

Regarding air intake (that you seem to point to as possible cause): does the stove burn "normally" when the door is closed? Same flames/action in the stove?

If so, it's not the air intake imo.

 

[begreen]

If so, it's not the air intake imo.

Agreed. It's unlikely unless the linkage arm to the air control is broken.