3 Sided Fireplace smoking

[bgxk]

Dear all

I am new in this forum I have a 3 sided glass fireplace which has no damper or any control of air.

It just sucks air form bottom as primary air and I guess from top as secondary air.

I am attachking here a few picture and videos to describe my problem and if you have ideas or things that you recommend me to check.

So the problem is that sometimes it does fire good but put smoke inside home/room as you see in first video its looking that is burning well but its pushing smoke inside from top side of glass as in picture with red draw lines.

In the video where you see smoke from top sucking in bottom that is how I see smoke ( air coming inside as secondary air ? in this video is when it worked well that smoke you see moved faster so chimney sucked better all this air - now when I burn fire that smoke goes at slower speed so it reverses a bit backside through top then smoke comes inside home/room )

I have lost a lot of time with inspecting chimney flue line and other things but I strongly believe that now all issue is on this fireplace since its not professional with air dampers air control etc and the distance in top where you see the air getting sucked for fire its big more than a finger place so is it possible that its too wide open and smoke tries to find other path instead of just sucking air from there...I am thinking of putting rope there in top of glasses to make that path more sealed I am suspecting its too open and that is reason why smoke doesn't sucked outside chimney at faster speed etc ?

Do you have any ideas or things which I can test/try I am open to try anything just to see if there is improvement.

I am outside of US from Kosovo but I found this forum helpful in fireplace stoves etc so I wanted to hear from any of you for my problem.

 

[Ashful]

Two things:

1. You probably already know this, but the draft created by a chimney is dependent on inside/outside differential temperature and chimney height, as well as many secondary effects (roof line, other appliances drawing air from home, the way wind affects the house, etc.). Cataloging these and tracking the condition of each at times when the stove works well versus not, will likely help reveal a culprit. Is it more troublesome only when it's warm outside, or when it's colder inside, when wind is from the west or east, when the clothes dryer is running, etc.?

2. Even with good drafts, there can be localized high and low pressure zones within the firebox itself. This is not a static vacuum scenario, but a dynamic region in which pressure everywhere inside the firebox is not the same. It may be counterintuitively creating some localized high pressure near that upper air inlet when draft is strongest, making for a very difficult problem to characterize. Again, tracking conditions when it works well versus not, can be helpful in diagnosis.

 

[EatenByLimestone]

Since you have 3 sides open, your flue might not be physically large enough to exhaust all of that air. Does it work better with all of the glass closed?

 

[bgxk]

Since you have 3 sides open, your flue might not be physically large enough to exhaust all of that air. Does it work better with all of the glass closed?

Flu size is 160mm inside and I keep all glasses closed as it is when I burn woods as you see in the videos.

 

[EatenByLimestone]

160mm is just over 6”. I’m assuming you have a round flue? That’s around 28square inches.

That’s very small for a fireplace.

Trying to get as little air into the fireplace as possible will probably help reducing smoke spillage.

 

[Ashful]

Since you have 3 sides open, your flue might not be physically large enough to exhaust all of that air. Does it work better with all of the glass closed?

That was my first thought at reading the subject line, but in looking at the photos it appears it is completely enclosed in glass, other than small vents at bottom and top. Right?

Agreed, any open fireplace with three sides is going to require a flue that gives serious legitimacy to the Santa conspiracy, if not enclosed.

 

[bgxk]

That was my first thought at reading the subject line, but in looking at the photos it appears it is completely enclosed in glass, other than small vents at bottom and top. Right?

Agreed, any open fireplace with three sides is going to require a flue that gives serious legitimacy to the Santa conspiracy, if not enclosed.

Yes this one is closed glass so I assume round 160mm its not small for closed one ?

Any ideas what I can do or how to measure draft etc to know if I have enough draft before doing any changes...is it an option to install fan cap which will suck more air in the outside from this type of fireplace I have ?

 

[Ashful]

A sensitive manometer (eg. magnehelic) with a metal tube that can handle high temperature, connected to the gauge by a rubber hose, could be invaluable here. It would allow you to insert the metal tube (think old scrap of steel automotive brake line) in thru a vent, and get readings at various locations.

Here in USA, we can pick up these magnehelics second-hand from HVAC technicians, for $30 - $50 on ebay. If going analog, you want something with a 0.25" (6 mm) water column at full scale, so that it has the resolution for 0.01" (0.25 mm) WC readings. Digital meters can work nicely, as well, but you won't find them for $30 on ebay.

As to whether your flue is too big or small, the readings would tell us, but there are also old tables published for a given fireplace opening. These assume an open fireplace, but I'd guess should give some relative idea for net inlet cross sectional area on a rig like yours, as well. I can't imagine that the pipe is too small for these little inlets, though, my money is on cold/short pipe phenomenon, or issues with your pipe not extending far enough above roofline or other nearby obstacles.

edit: I just reviewed, and it seems the old rule of thumbs were that a square flue should be no less than 1/10th the size of the total fireplace opening, and a round flue no less than 1/12th. If you treat your total cumulative inlet size, including all sources of leaks, I can't imagine you're below these guidelines on a 6" round flue, but worth checking.

 

[bgxk]

Thanks for explanation well here in our country standard is 160-180mm round sometimes at 200mm max for big coal boilers for example in my garage I have my coal boiler 48kw with 200mm round chimney flue.
To get that tool to measure my draft will take me time until it arrives for delivery...so is it an option to buy a chimney cap with fan or can I use this type of ventilation cap I have on with bearing as this one in picture is it going to help anything ?

 

[EatenByLimestone]

Wood and coal stoves control the air entering. The size of the inlet(s) are very small. There may be enough leaks around doors, actual inlets, etc to overwhelm the flue.

A fan on top might make a difference. I suppose it depends on how much air the fan moves.