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10-09-2006, 15:09   #1
iplogger1
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Downdraught prevention chimney cowls

I was wondering about these. Pros/cons.
I see there are rotating and stationary versions... the purpose, I assume
being to prevent a downdraught from causing a smoke down situation
at the fireplace.

I've seen the rotating ones occasionally.

Someone mentioned them to me but didn't know much about current
thinking on them. Up until know I assumed I'd just put one of those
standard cast iron cowls which keep crows out,etc.

eg:
http://www.hotline-chimneys.co.uk/cowls_main.htm
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10-09-2006, 17:03   #2
rooferPete
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Hi,

If you have a down draught problem there are a lot of different cowls on the market, each one has purpose so it's best if you know the cause before spending on a cowl.

One of the oldest and in my opinion still the best multi purose cowls is the "H" cowl, maybe not the prettiest but they have always worked for me.

.
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11-09-2006, 11:28   #3
iplogger1
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Thanks for the advice Pete.

We haven't moved into the property yet. In fact they are just plastering
the chimney this week ahead of slating the roof. The topic only came
up when I told my father in-law that I purchased a nice pair of
chimney pots. He asked if I was thinking about putting in a cowl to
avoid "smoked downs". I hadn't even thought about anything other
than the standard inverted cast iron cone shaped cowls.
I guess it is premature for me to be worrying about downdraught
cowls until we've actually lit a few fires and established if there is
a downdraught problem or not.

thx again
~ipl
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15-12-2006, 12:57   #4
padraic mchale
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Quote:
Originally Posted by rooferPete
Hi,

If you have a down draught problem there are a lot of different cowls on the market, each one has purpose so it's best if you know the cause before spending on a cowl.

One of the oldest and in my opinion still the best multi purose cowls is the "H" cowl, maybe not the prettiest but they have always worked for me.

.
Hi Rooferpete

i have a down draught problem and i had a guy look at it. He also recommended the H Cowl but they seem to be very expensive €290 euro each plus 100 euro installation cost. This is for a terracota cowl. Do you know of anywhere cheaper?

thanks,
Padraic
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16-12-2006, 22:36   #5
karltimber
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Quote:
Originally Posted by rooferPete
Hi,

tne of the oldest and in my opinion still the best multi purose cowls is the "H" cowl, maybe not the prettiest but they have always worked for me.

.

does anyone have a picture of this type of cowl.

K
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17-12-2006, 10:50   #6
serotonin_sam
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Quote:
Originally Posted by karltimber
does anyone have a picture of this type of cowl.

K
H Cowl

I never use my fireplace and have a chimney balloon placed above the fireplace opening. However, when there are strong winds, I still get the impression that its causing a draft. As well as down-draughting, do cowls play a role in reducing draughts? If so, which one should I get bearing in mind I have no intention whatsoever of using the fireplace over the short/medium term.

Last edited by serotonin_sam; 17-12-2006 at 10:59.
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22-12-2006, 12:24   #7
padraic mchale
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ttt
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23-12-2006, 20:26   #8
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I've seen a cowl that has a chain that drops down the chimney so it can be opened and closed depending on whether or not you want to light a fire. I use my fireplace regularly so don't want it to be blocked in any permanent fashion. I'm thinking of getting the chain type. I tried to find the link (without success) to a supplier in Ireland that I've seen before - if I find it I'll post it.

At the moment, when I suffer from downdraught in the chimney I simply light a a sheet of newspaper, and shove the lighted end up the chimney as far as I can. (don't let go of the paper!!) - this heats the chimney and reverses the draught's direction to an updraught. Its a temporary solution but it works.

EDIT: Found link > here.

Last edited by crosstownk; 23-12-2006 at 21:58. Reason: Link Added.
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23-07-2009, 09:52   #9
eddie4
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as has already been said there are a number of causes of down draught, and many differant cowls, as a chimney sweep i agree that the h pot is an excellent soloution but does present problems when it comes to cleaning and also preventing qour feathered friends from gaining access to the chimney. If the problem is not excessive then a standard static anti downdraught cowl is fine, supplied and fitted 90 euro if a spinning cowl is required the cost should be no more than 150 both are available from heiton buckley.
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25-07-2009, 11:31   #10
mrtom
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Spinning cowles

Eddie4, I need to sort out my downdraught problem caused by a higher neighbours roof. Only happens when the wind is blowing a certain direction.
I like the prices you mentioned for supply & fit. Can you advise me on who I can contact to do the job. I live in the Dunlaoghaire area.
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25-07-2009, 11:45   #11
aujopimur
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Wait until you have your fire lighting in all weather conditions before you decide on a cowl.
Most fluing problems are caused by poor constuction or flue location.
With regard to draughts from fireplaces most people are under the impression that air is coming down the chimney when in fact its the opposit .
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25-07-2009, 19:03   #12
eddie4
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hi mrtom we cover your area, not sure on the ethics of posting contact details on here but if you would like to contact me my number is 085 1665807.
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25-07-2009, 22:28   #13
mrtom
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Thanks, will be in touch.
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29-07-2009, 21:02   #14
sooty_soupy
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Just be very careful guys that it is actually a blowdown problem. For over 20 years I have been a registered chimney technician in the North and have trained many people over the years. I am Chairman of the Northern Ireland Association of Chimney Sweeps and am a technical advisor to Building Control here in the north.

Blowdown is often a term used freely when smoke is spilling back into the room. This can be caused by a number of issues. I agree that higher properties, trees or hills can pose a serious problem, but would also suggest that some cowls are significantly better than others. Blowdowns often are when the wind is coming from the direction of higher obstrctions placing the termination point in the pressure zone of the roof. This can be helped by putting a permanent vent on the wall to equlaise the pressures.

Smoke could also be coming back into the room by something as simple as an extractor fan in the property creating a negative pressure in the home, or air tight construction leading to air starvation, effectively smothering the draught required to vent the flue gasses correctly. Finally it could be a ratio problem, where the fireplace is too large in dimension for the diameter of flue. If it of any use to you, the solution to ALL of the problems above is to fit an electric fan, if your finances allow, otherwise expect a lot of headaches and expense trying to cure it with cowls. The art of chimney building has unfortunatly been lost through the years.

Hope this helps.

David
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04-08-2009, 03:03   #15
DougB
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Chimney Balloons

Quote:
Originally Posted by serotonin_sam View Post
H Cowl

I never use my fireplace and have a chimney balloon placed above the fireplace opening. However, when there are strong winds, I still get the impression that its causing a draft. As well as down-draughting, do cowls play a role in reducing draughts? If so, which one should I get bearing in mind I have no intention whatsoever of using the fireplace over the short/medium term.
I always thought that if you stop up the flue that you lose ventilation for the house, especially if its an older house with now window vents etc.
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