Smoke from fire not going up flue

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Green

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Having a few problems with smoke from our open fire circulating around the room its in. I put a cap on the chimney pot before Christmas which has stopped downdrafts and initially it worked fine, no down draught and smoke escaped. However, recently smoke is not going up the flue as readily and circulating in the room. Any thoughts appreciated.
 
From what you're saying it seems you may have put the wrong type of cowl on your flue but then again you haven't told us much about it. Also, the flue may be below the ridge, or surrounded by trees. There's many things that could be causing it.
 
Thanks noproblem attached is a link to the chimney cowl I used.

https://www.amazon.co.uk/d/DIY-Tools/De-Vielle-Terracotta-Chimney-Cowl/B00HHASDVO/ref=sr_1_11?ie=UTF8&qid=1485626006&sr=8-11&keywords=chimney+cowl
 
Not a good choice i'm afraid, that's a static cowl. You need something that will twist away from the downdraft, but as I said, it may be one of many problems causing your fault.
 
Is this problem more likely to happen the colder the weather?
I can't remember the name for it but it's common with flues.
A pocket of cold air is forming inside the flue. The relatively cold early-fire smoke cannot penetrate it. You need to generate a fast blast of hot air to punch a hole thru that cold pocket.
Before you light the fire, light a sheet of newspaper and hold it near the top of the stove/fireplace. You need a good flame so make sure you haven't the newspaper balled up. With a bit of trial and error you'll figure out how many sheets of newspaper you'll need. One usually suffices for me.
Another problem can relate to disparity in air pressure. Open the window for a few minutes.
I don't know much about cowls though some can be quite aesthetic.
 
Drakon said:
Is this problem more likely to happen the colder the weather?
I can't remember the name for it but it's common with flues.
A pocket of cold air is forming inside the flue. The relatively cold early-fire smoke cannot penetrate it. You need to generate a fast blast of hot air to punch a hole thru that cold pocket.
Before you light the fire, light a sheet of newspaper and hold it near the top of the stove/fireplace. You need a good flame so make sure you haven't the newspaper balled up. With a bit of trial and error you'll figure out how many sheets of newspaper you'll need. One usually suffices for me.
Another problem can relate to disparity in air pressure. Open the window for a few minutes.
I don't know much about cowls though some can be quite aesthetic.
Click to expand...

I bought the cowl before Christmas and everything was fine. it's only very recently that the problem started. Last night I lit a big fire and when its started and going strongly there was no smoke but as the fire receeded it started to smoke again.
 
noproblem said:
Not a good choice i'm afraid, that's a static cowl. You need something that will twist away from the downdraft, but as I said, it may be one of many problems causing your fault.
Click to expand...


https://www.amazon.co.uk/Stainless-Rotating-Chimney-Anti-Downdraught-Standard/dp/B01A42E2CK/ref=sr_1_2?s=diy&ie=UTF8&qid=1485808642&sr=1-2&keywords=chimney+cowls

Do you mean this type of cowl?
 
Yes, maybe. Like I said at the outset it could be many things. BTW, I don't know the name of the gadget but there's a measurement device for checking chimney pull, draw, whatever.
 
Have you tried opening a window or door in the room ? it might not be getting enough air.
 
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