Running DIY WoodStove over night in a small cabin & safety issues
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In reality, if the fire is left on a reasonable draw, i.e. plenty of air is entering, supporting combustion, and leaving with the hot gases via the flue, there should be no problem at all. The problems only start when people shut down the stove, restricting the airflow, to keep the fire in over night etc.
When you say shutdown the stove, does it mean the front stove door or the pipe damper?
Should both be kept open?
On most stoves there’s an adjustable air vent at the base and on some a damper in the flue. The damper should never be closed completely or the gasses have no way of escaping except leaking into the room/tent. Ideally, the flue should stay partially open and the draw vent not fully closed. It will burn more fuel but be safe.
Modern household stove no longer allow complete closure to prevent unburnt gasses getting into the atmosphere.
I totally agree that there must be sufficient gas flow throughout the stove system
-from inlet vent, through the fire box and out into the atmosphere via the flu-
to exhaust all gases.
But
With a wood fired stove this much air movement can be make it difficult to maintain heating all night.
I don’t use tent heating at all but in a cabin I just kept it going until I fell asleep and relied on bedding and clothing after that.
-from inlet vent, through the fire box and out into the atmosphere via the flu-
to exhaust all gases.
But
With a wood fired stove this much air movement can be make it difficult to maintain heating all night.
I don’t use tent heating at all but in a cabin I just kept it going until I fell asleep and relied on bedding and clothing after that.
Good info, thanks. I have seen a wood stove smoking excessively when the pipe diameter was reduced to half by the pipe reducer (127mm to 60mm) even with the front door air vent fully open. It wasn't burning as such but just smoking out. What could be the reason for this?
Doesn't the pipe damper when closed half, do the same effect as the reducing the pipe diameter by the reducer, causing the stove smoke excessively?
Stoves differ so much. If I were you I’d do some experimenting (in daylight) and find out what works with yours.
We can’t give you any hard and fast formula at a distance.
You are going to have to find a balance between air input, flu output and fuel loading.
We can’t give you any hard and fast formula at a distance.
You are going to have to find a balance between air input, flu output and fuel loading.
A fair point. Yes, stoves can be all different in the modus operandi suppose.
In fact, it could have been the fuel incomplete seasoning which caused excessive smoke too. But I was concluding that the pipe reducer was the culprit for the excessive smoke of the stove, because the other stoves with their own pipes have never shown the symptom. I am still not 100% sure on the exact cause of the excessive smoke from the pipe in the log burning session with the particular stove.
I must do some testing with various setting in the stoves and logs and the pipe settings. I am trying to learn on the fire craft with the log burners in the garden.
Problem is that people around here don't seem liking the smell of wood burning. I am a bit cautious when to start the log burning, which are mostly in the evenings and nights trying to avoid times when anyone is still hanging out their washings in their gardens.
No stoves are fully sealed, if they were, there would be no oxygen getting in & the stove would go out.
The important thing is to have a good sized exit for exhaust gases and a good source of fresh air into the room.
Remember the triangle of heat, fuel and oxygen. Flues act to suck air into the stove and out through the flue. Heat increases this as does airflow over the cowl (wind).
Thing about blowing on a coal with a bellows. Reducing airflow through a flue in a well regulated stove should reduce the blast of air that turns it into a blast furnace. It should not deprive it of sufficient oxygen to burn cleanly.
You noted that the stove wasn't sealed. If there is reasonable airflow into the cabin, then there should be sufficient oxygen entering the stove to prevent carbon monoxide forming
One can take the air for the stove directly from outside, then the stove can actually be totally sealed. That is sometimes done with very small cabins that are very airtight. The alternative is to have large enough air vents, that can be a problem in very cold surroundings.
The farce is the regulations here require you to have an external air vent into the room for a stove over 4.5Kw (IIRC). We had a new stove put in a few years back, we live in a 350+ year old barn, stopping the drafts is impossible! I sealed the external vent up as soon as the fitters had left 
I'm more concerned by a throttled flue than a mostly shut down air inlet.
Both produce carbon monoxide but the open flue is better at getting rid of it.
Both produce carbon monoxide but the open flue is better at getting rid of it.
I have the other smaller portable woodstoves using 60mm pipes with 90 degree elbows, spark arrester and rain cap. These bits were very pricy for 127mm flue, but cheap for 60 mm, hence I got the 127 to 60mm reducer.
The DIY stove of the youtuber "Lone Scavenger" looked a bit dodgy for smoke leaks, but then it is an impression from the images in the videos, and the actual situation might be different. I was just guessing. It looked an unsafe stove for running overnight in a confined space while someone sleeps in it.
But as you say, if there is good air flow into the cabin, stove into the flue, it must be safe.
Afterall he must have been using the DIY stove in his cabin for sometime without safety problems of the stove.
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The farce is the regulations here require you to have an external air vent into the room for a stove over 4.5Kw (IIRC). We had a new stove put in a few years back, we live in a 350+ year old barn, stopping the drafts is impossible! I sealed the external vent up as soon as the fitters had left
All that work to make a building “air tight” for insulative reasons and then they want to add a vent.
When I did mine I remember part of the procedure was to check the flow of exhaust fumes and then open a window. If the draught increased you needed a vent, if not it was fine. I’m sure there was more to it than that though and no two buildings are the same.
I cannot speak about your specific installation but I think that there is a big difference between a system designed with a 60mm flu and one designed with a 127mm flu that is choked down to 60mm especially if the air input isn’t balanced with the flu output.
The stoves with 60mm pipe tend to have smaller firebox. They are mostly for camping portable wood stoves.
The 127mm flue pipe is for the larger woodstove. The stove is about twice to thrice the size of firebox space.
When the 127mm flue was reduced to 60mm, the stove smoked a lot with strong wood burning smell. I was wondering if it is caused by the reduced flue. But then there are other factors which might cause excessive smokes in the burning such as type of wood (incompletely seasoned, trees which are not suitable for wood burning stove such as alders and some other unsuitable woods), or over filling the stove before starting.
From the start, the stove was not enthusiastic in burning, and fire was keep dying with lots of smoke. I kept on lit the woods in the stove with a gas torch. The fuel woods in the stove were surely dry enough then, but it just burnt with ambers rather than flames with loads of smoke whole session. It was first time I have seen poor burning like that. Will give another try with the 127mm pipe alone.
On the night I was not sure what might have been the real cause for excessive smoke from the pipe.
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