Coal fire

[Louisa]

We have opened up a second fireplace and installed a cast iron insert.
Not dissimilar to this design

http://www.artisan-design.co.uk/f/product_image_71.jpg

The chimney is drawing beautifully but we are getting a lot of back draft which obviously is filling the room with smoke.

A corgi registered guy said, these designs can be quite a pain until they warm up?

We know the chimney is clear so does anyone have any ideas what it could be?

Thanks in anticipation.

 

[biffvernon]

Excuse me, but if the room is filling up with smoke then the chimney is not drawing beautifully. When you first light the fire open the nearest window or outside door to ensure there is plenty of air to go up the chimney. Once the chimney is warm it should take care of itself but, of course, the room has to be draughty enough for all the smoke going up the chimney to be replaced by fresh air coming into the room through air-bricks, and cracks round windows and doors. If you've been a good girl and draught-proofed the house you may have to leave the window ajar. That's the trouble with open fireplaces. A lot of coal heats up and pollutes the night air.

 

[Pford75]

It may also be worth considering a cowl on your chimney pot. We had one fireplace in a previous house where the pot was exposed to the prevailing wind...once we installed a cowl, we had no further problems.

NB - If your house is listed, you should confirm with your CO if consent is required

 

[Nemesis]

We removed our cowl as it stuck at times and the wind blew smoke back down!

Many people in Northumberland have fitted these:

http://www.erringtonreay.co.uk/company_web/er/story4.htm

Similar anti-downdraught designs can be bought, as can an off the peg metal pot insert which isn't pretty but can be a cheap and effective solution. I think ceramic ones can also be bought.

But - so much is trial and error really.
No simple answers to blowback.

The chimney must be warm for a fire to draw properly;

It helps if there is a fireback installed to restrict the throat of the fire (four inches I think - Count Rumford);

Height of chimney pot can be a crucial factor;

Nearby buildings and tall trees can interfere with the draught.

 

[Lime]

This type of fire is well designed and doesn't usually have problems.
The problem appears to be (judging by the description) that although the fire draws well most of the time on occasion the fire "blows-back" into the room.
This is caused by wind eddies above the chimney pot and is often created by nearby tall trees or other higher objects in the vicinity.
Sometimes a cowl can cure it, sometimes not.
However as biffvernon points out the air going up the chimney has to come in the room first. If the room is sealed then that won't happen.
It sometimes depends on the shape of the house and whether the wind creates a partial vacuum in the lee of it.
This can then result in a lower air pressure within the house that can cause smoke to be drawn down the chimney too.

 

[Louisa]

Thanks for your advise everyone.

I will let you know how we get on.

 

[Flyfisher]

A corgi registered guy said, these designs can be quite a pain until they warm up?

My experience bears this out. When we light our first fire of the season, blow-back can be a problem. But by the time the weather changes such that we have a fire every day there is no problem at all. I've always assumed this is because the chimney remains warm.

Might be worth persevering for two or three days and see if things improve.

 

[Louisa]

Well we did and so far we have had no blowback.

Perhaps the couple of times we have tried the wind was against us.

Because there is nothing wrong with the draw.

 

[Flyfisher]

Good news; a warm chimney can make all the difference!

Another trick I use before lighting a fire under a cold chimney is to screw up a page of newspaper, stick it up the chimney and light it. The brief burst of heat will push out the 'plug' of cold air in the chimney reducing the chance of blow-back when lighting the fire.

 

[Louisa]

That's a good tip, thanks for that.

It lovely having both fires lit tonight.

 

[biffvernon]

Another tip for getting the fire going is to hold a single sheet of newspaper right across the whole opening except right at the bottom, where the air can enter. If you haven't done this before you may be surprised at the effect.

Make sure it is a single sheet. If you use a double sheet the one will insulate the other and the fire side sheet will burst into flame, but a single sheet stays cool enough for a long time and you can see it turning brown long before it actually catches fire.

The fun of an open fire place.

Now go and get an enclosed woodstove that heats the room more efficiently.

 

[Nemesis]

Buy or make a metal blazer. The sheet of paper goes on the outside of that.

 

[Moo]

"..screw up a page of newspaper, stick it up the chimney and light it. The brief burst of heat will push out the 'plug' of cold air in the chimney"

We were told by some old-timers that we should stand lighted candles at the bottom of our Aga flue before the ritual winter lighting. This would, apparently, heat the cold air that had been sitting in the flue.
It didn't work, I'm afraid (perhaps we were too mean with the candles) but we applied the principle in the form of a gas-poker and that worked a treat.

 

[Raylea]

We do the sheet of newspaper trick over the hole and leave a gap, it does work a treat, but you do have to be careful our chimney sucked the newspaper in and it caught fire. (The other half still had, then all of a sudden he was flapping like gooden) :roll:

Raylea

 

[Penners]

perhaps we were too mean with the candles

You have to think big...