Smoke from stove into room!

jakko86 · 20-11-2014 11:51pm #1

Hi all I recently bought a barbas inset stove and it works fine until I need to open it to load it smoke comes back into the room from it, i leave the door slightly open before I open door fully to load but still smoke comes out! It has an external air supply so I can't understand it! It's flu is brought up to the 9inch gatherer where it meets the clay pots. There is a turn low down in the chimney (2 clay flu bends together) is this the problem I wonder? Would a spinning cowl help? Any advice would be great.

scudo2 · 21-11-2014 9:29am

I don't know the answer.

But a carbon monoxide alarm is critical for all stove users, hope you have one.
If you don't, get one pz.

therealmccoy · 21-11-2014 11:52am

jakko86 wrote: »

Hi all I recently bought a barbas inset stove and it works fine until I need to open it to load it smoke comes back into the room from it, i leave the door slightly open before I open door fully to load but still smoke comes out! It has an external air supply so I can't understand it! It's flu is brought up to the 9inch gatherer where it meets the clay pots. There is a turn low down in the chimney (2 clay flu bends together) is this the problem I wonder? Would a spinning cowl help? Any advice would be great.

It sounds like you have a poor draw on that chimney or that the chimney might be too cold to draw. Do you light a good strong fire? If so then it's the draw.
Things to improve that is to put in a flexi liner. This would be my first recommendation. Other than that a spinning cowl might be ok but you may need a motorised spinning cowl which will work.

Did whoever installed your stove do a test on the chimney air flow before the stove was installed?

tommer · 21-11-2014 2:58pm

I Think you need your chimney cleaned also open air regulater before opening door

donedl1 · 21-11-2014 3:27pm

Is there purpose provided ventilation and if so how much?

cranefly · 21-11-2014 4:43pm

I find the way you stack your fire with coal or timber can have a big effect on whether it will smoke into the room when you open the stove door.
The best way for me to lessen smoke coming into the room is to build the fire at the back of the stove and have it sloping down at the front like a mountain, mine is a boiler stove so that is the best way to have the water heated quickly, smokeless coal will have a way better effect at less smoke as well.

crock! · 21-11-2014 6:57pm

jakko86 wrote: »

Hi all I recently bought a barbas inset stove and it works fine until I need to open it to load it smoke comes back into the room from it, i leave the door slightly open before I open door fully to load but still smoke comes out! It has an external air supply so I can't understand it! It's flu is brought up to the 9inch gatherer where it meets the clay pots. There is a turn low down in the chimney (2 clay flu bends together) is this the problem I wonder? Would a spinning cowl help? Any advice would be great.

Is the pipe from the stove tied into the 8 inch with a reducer or another way

jakko86 · 21-11-2014 8:44pm

Sorry about the delay getting back, it's a double sided stove barbas 70/55 tunnell I don't think there was any test for draw as the guy who fitted lit a couple of newspapers and said " great draw there" so I took him on that it's a wood burner and it's piped with a joiner to the clay liner with same diameter stainless pipe? It's has an external air supply 4 inch pipe to bottom of unit. When the door is closed it burns great and holds no smoke and is fast to lite up from the start?

tele2 · 23-11-2014 12:38am

Had the same issue

Try this

Start a good fire with kindling

Add solid fuel - dry wood, turf coal etc

Open ash drawer to vent it if vent controls aren't sufficient to get a roaring fire going

If it smokes into the room before getting going light a sheet of newspaper and open door and pop in - this will get a good draught going

When fire is well lit close ash drawer and back off vent controls

Top feed for wood, turf

Bottom feed for smokeless coal

Works for me

sky6 · 23-11-2014 10:23am

Are you in a Bungalow.
Are there hills close bye.
Are there Trees close by.
Have you got 2 chimney pipes close together on the roof. One should be higher than the other.

Any or all of these will contribute to poor draw, smoking and downward pressure.

sky6 · 23-11-2014 10:42am

Something else I just thought off is maybe the external air supply is to strong.
For a fire to burn properly the Chimneys needs to heat quickly which creates the vortex and draw. The cold air entering the fire might be to strong and slowing the chimney from heating.If the pipe run carrying the cold air is long it will create it's own vortex increasing the pressure when it reaches the fire.
Maybe slow it down a little at a time and see how it performs or see does it make any difference.

Chimneys are so simple in context but in fact are very complex. Physics plays a huge part in designing any chimney properly. There's no one size fits all.
They should each be calculated properly to ensure they will do the job for the house being built. Otherwise people are trusting to luck and in some cases playing with lives.

As said previously at least make sure you have a Carbon monoxide alarm.

goldsalmon33 · 29-12-2017 5:41pm

Any update on this thread OP? Have the same issue with a double sided cassette stove myself. Burns grand and can even quench fire by closing draft fully. But to add timber means opening the door and thus allowing smoke to enter room.
It's a wood burning stove so timber only and it burns on a bed of ash. As in there is no grate. It's worse at start when more smoke is present before a flame appears but smoke still comes out the door every time it's opened.
Chimney is lined with flexi liner and stove has its own as air intake.

my3cents · 31-12-2017 1:20pm

goldsalmon33 wrote: »

Any update on this thread OP? Have the same issue with a double sided cassette stove myself. Burns grand and can even quench fire by closing draft fully. But to add timber means opening the door and thus allowing smoke to enter room.
It's a wood burning stove so timber only and it burns on a bed of ash. As in there is no grate. It's worse at start when more smoke is present before a flame appears but smoke still comes out the door every time it's opened.
Chimney is lined with flexi liner and stove has its own as air intake.

This is an old thread but I'll give one possible answer to your question anyway.

AIR PRESSURE.

When your stove is working away with the door closed, for various reasons including the length and height of the chimney plus heat from the fire, the pressure at the top of the chimney is lower than at the bottom, hence the air (or rather smoke) flow is up the chimney. Even with no fire you have this air flow.

You have a closed system where the air pressure outside where the air comes in from is higher than the air pressure in the chimney so when the door is shut it all works fine.

Now if opening the door messes this up there can logically really only be one reason.

The air pressure in the room is lower than at the top of the chimney or lower than the air pressure of the air coming in via the external vent either of which will allow smoke into the room. Its very possible that the cold air coming into the stove from outside carries on rushing in when the door is open so pushing the smoke into the room.

You can't block the external air vent for obvious safety reason plus the fire wouldn't work so all you can do is allow air into the room from another source. A hit an miss vent near the stove from outside could allow you to open it before opening the fire door but hard to say if it would totally fix the problem.

If you have any form of positive ventilation pulling air out of the room then that will make the problem worse. You might like to try opening doors and windows before opening the fire door to see if having another air source prevents the smoke leaving the stove when the door is open. Sometimes a door or window open even slightly on one side of the house will make the problem worse where an opening on the opposite side makes it better. Its all to do with the minor changes in air pressure that make a chimney work. It might even help if the air pipe for the fire is on a different side of the house.

The bottom line is that air has to be drawn into the fire from the room when you open the fire door if it isn't then smoke will come out. The movement of air is governed by differences is air pressure between two points.

goldsalmon33 · 03-01-2018 8:34pm

So air flows from any area of high pressure (the fire) to an area of low pressure (top of chimney)? So opening the door changes this by providing a lower pressure area for the smoke to go rather than up the chimney. and air continues to push in from outside and force the smoke out the door. Maybe if i closed the draft fully say 10 sec before opening the door to stop new air coming in that way no new air can push the smoke out?

my3cents · 03-01-2018 9:06pm

goldsalmon33 wrote: »

So air flows from any area of high pressure (the fire) to an area of low pressure (top of chimney)? So opening the door changes this by providing a lower pressure area for the smoke to go rather than up the chimney. and air continues to push in from outside and force the smoke out the door. Maybe if i closed the draft fully say 10 sec before opening the door to stop new air coming in that way no new air can push the smoke out?

That would be a good start. If it doesn't or only partially helps then try opening the door or a window a bit first.

Smoke from stove into room!

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