chimney problem

[gimbals]

We have had a real coal effect gas fire fitted in our louge complete with inglenook fireplace. The problem is that when we have all doors to the room closed, we get a smell of fumes in the room. Initially, we thought it was because the installers did not fit an air vent - so I fitted one. I removed 2 x 9inch bricks and fitted an air brick and covered it with a permanently open "marley" cover in the room. The problem is still there, albeit a little better. Further examination found that the distance between the top of the fire basket and the chimney opening is approx 8 inches more than it should be. This is because the base of the original fireplace was 8-10 inches above the floor level. When the new fireplace was fitted, they lowered the floor of the fireplace to floor level.
unfortunately, the company who fitted the fire have gone bust so I am left to fix the problem myself. As I see it, the solution is to reduce the gap between the top of the fire basket and the bottom of the chimney. The question is how?
I have had the chimney checked and it is ok.
Can anyone help? A picture of the fireplace can be found here
it is the second one down on the right.

 

[another_sparky]

I'm not a 'gas' man' but, it sounds as thoguh fumes are drfiting up over your mantle

how about a canopy?

 

[masona]

When was the chimney last swept ? I would get this done first before you do anything as you might have a reduce air flow.

 

[DAZB]

Do you have a cowl fitted to your chimney because this would help draw the fumes up more efficiently.
One of these or something similar is what I mean.

 

[gimbals]

i do not have a canopy fitted, it's just the standard chimney pot. I have had the chimney tested and am told that it works fine. Does the cowling increase the draw up the chimney beyond that of a normal efficient chimney? My line of thinking is that we had no problems at all with the original fireplace which was raised off of the floor by 8-10 inches. I have read that there is an optimum distance between the basket and the bottom of the chimney which, if exceeded, will result in a less efficient extraction of fumes. Given that the original distance has been increased by lowering the basket, I think that I could solve the problem by fitting some sort of hood to the bottom of the chimney (it would be hidden behind the fascia of the fireplace). The hood would reduce the gap between the basket and bottom of the chimney. Is this a sensible theory and where do I get a hood?

 

[gimbals]

we had the chimney swept and tested last month as part of the investigation.....

 

[DAZB]

The cowls are designed to draw the fumes up the chimney when the wind blows them round creating a centrifugal force a little like a Dyson vaccuum if you see what I mean. It may work for you by fitting a hood of some description but you may have to have one made to fit by a local metalwork firm who can also shape it for you if needed. It shouldn't be too expensive as it will only probably be a off cut from a 3mm galvanised sheet or similar but not quite sure how you intend to fix it in place without removing the fire surround.

 

[gimbals]

thanks dazb - i like the idea of the rotating cowl and have just found details on a web site. apparently it increase the draft and comes with an unconditiona, money back guarantee to fix the problem. I guess it's worth a try before resorting to metal work inside the fireplace.