Chimney Backdrafts Caused by Installation of a Second Fire

[gizmo_the_great]

Hi

Moved into a 1930's house. It has a dining room at the front of the house and a lounge next to it -both rooms have a chimney.

We had a real fire fitted this time last year in the front dining room and have used it without problem. It has never been swept.

The other day we had a gas 'real flame effect' fire fitted in the lounge. We had that chimney swept (it had a lot of black soot in it).

Problem : Since having the 'real flame' fire fitted in the lounge, whenever it's on, a draft has developed in the chimney of the real fire in the front dining room to such an extent that it wafts the smoke into the dining room while it gets going, although it lessens as the fire gets going and hot. It didn't used to do that. What's worse is that even when the real fire is not even burning anything (i.e. off) the smell of it's ash and coals is being wafted into the dining room and hallway by a cool breeze blowing down the chimney which I am sure it did not do before.

When both fires are off, there's no apparent smells.

Why is this happening? What should I do?

Thanks a lot

 

[joe-90]

Every chimney I have ever seen has total separation between the two, they are simply separate chimneys side by side. Are they still separate?

 

[gizmo_the_great]

Oh Right. I did not know that. I assumed they merged into one at some point further up the building.

Yes, no structural work has been done to them to merge them so I assume the answer is yes, they are still seperate. There is two pots on top of the chimney with two bird cages.

My friend told me today that this problem can sometimes happen when it's a really still night (i.e. no wind) because wind causes draw from the chimney. When there is no wind the cool air just falls down the chimney.

Perhaps this is the case - maybe it's just that it was particularily still on Friday night causing the backdraft. ?? I had just assumed it was due to the additional fireplace being fitted as I'd not experienced this problem before.

 

[JohnD]

more likely a crack between the two flues.

If your local chimney sweep is experienced, he is likely to be able to advise on what the problem is, and local people who can fix it. Chimney sweeps develop expertise in this area as no-one else is very interested in chimnneys.

The gas fire flue could have a liner put it at fairly low cost, but sealing the chimney for a coal fire is an expensive and specialist job.

A leaky flue can be very dangerous, especially from a gas fire where there is no visible smoke.

 

[gizmo_the_great]

Ah, that reminds me. When the old gas fire was removed, my wife tells me that they also took out a large pipe from the chimeny which I assume was the flu liner? Maybe as a result of them removing that it has exposed a crack between the two chimneys resulting in a gaseous exchnage between the two chimneys??

 

[JohnD]

possibly.

maybe there were old cracks which had been clogged with soot.

flue liners for gas can be simple metallic tubes, usually flexible, fairly cheap and easy as they do not get as hot and sooty as coal or wood fires, which need a large open flue, lined with smooth mortar. I believe it is possible to fit an iron flue, but as few chimneys are perfectly straight, this is difficult after the house has been built.

 

[gasmick2]

hi this a a problem that you get with putting a gas fire in the same room as an open fire its not advised thing to do , a thing you can try is when its doing it open a window in the part where the open fire is and see if it stops it smoking back if it does and i do not see why not then measure the opening area and fit an air brick to equall the size of the opening,

i know of an old lady that died because of 2 different fires fitted she fell sleep and the gas fire was on and the solid fuel was lit as time went on the solid fire stared roaring away and drew the fumes back down the gas fire flue because it caused a suction in the room and a solid fire has no controls to stop it from roaring away so check it out and be safe
it should be checked with smoke bombs then you can see what is happening

 

[joe-90]

When I was a kid we had coal fires and it was commonplace to get a blowback every now and again. We'd often have the room filled with smoke. It's all about air pressure outside, and as far as I know, there is nothing you can do about it.

 

[Robbie uk]

Does the chimney with the gas fire have a gas pot on the top or is it just an open pot. If open then too much air can be drawn back down when the open fire is working. try looking at this forum , http://www.itsnoteasybeinggreen.org/forum/viewforum.php?f=34&sid=be1a3a6fa0a36b7c287dd890d238a18e they know everything about fires.

 

[Nige F]

Put this in the plumbing/heating forum and get the corgi boys to opinion it ....you` could have a Serious Safety Issue here I know I take the **** out of corgis ...but only their charges££££ . I wouldn`t use that gas fire myself

 

[AtoZ]

if you have your gas fire on it needs oxygen,
i would have thought the easiest way for the oxygen to get replenished is for it to be drawn in down the other 'cold' chimney, hence the smell.

i think gasmick2 and nige f gave you sound advice.
its worth getting it checked out i reckon