Pressure

[MarineScott]

Does barometric pressure have any thing to do with starting a fire?..........high or low pressure systems?
Every once in a great while it seems to be difficult to start a fire, once going it is ok. Just curious. We start the wood stove the same way every time, wood and kindling well seasoned......Hmmmm.

 

[Odog]

I've had that problem, thought my stove pipe needed to be taller to create more draft, still didn't work. Seemed like the cold air was to "heavy" and the smoke wanted to come out the door instead of up the pipe. I actually opened the front door of the house and the fire started going. I still haven't figured out why

 

[unclemoustache]

Draft is probably the problem. My chimney is on the windward side, and I often have a backdraft coming down the chimney. I keep a hair dryer by the stove to push it back up, then I light some newspaper to get it going strong, THEN I light my fire.
Once in a great while that all backfires and I get a boat-load of smoke coming back in the house and the smoke detectors drive us batty. Never a dull moment in my home!

 

[hupte]

ever notice that the coldest part of the day is just before the sun comes up? why? its the same reason as your talking about. its because as the sun rays start shinning over the apex of the earth they heat up the air and push all the cold air downward toward the earth. which in turn pushes down the air down into your chimney. and opening the front door will counter act the cold air pushing down thru your chimney. hence the heat in your house will rise up thru the chimney. i've always had the hardest time lighting a fire at dawn and dusk. or at least thats my understanding. hope this helps

 

[turnkey4099]

I've had that problem, thought my stove pipe needed to be taller to create more draft, still didn't work. Seemed like the cold air was to "heavy" and the smoke wanted to come out the door instead of up the pipe. I actually opened the front door of the house and the fire started going. I still haven't figured out why

Same here but I found if it put ssome crumpled paper on top of the wood under the pipe and light that off, then the paper under the wood it cuts down the problem considerably.

Harry K

 

[Motorsen]

It's a temperature problem. You need a temp difference to create draft. If you have a cold chimney with the same or near the same temp as outdoor there will be no raising of relatively warm air upwards in the chimney. As soon as the air in the chimney heats up it will draft upwards. If the chimney is really cold it will cool off the exhaustgasses quickly to the surounding materials temperature and then no or little draft is experienced. We need to heat the chimney fast with a quick hot burn to get the local weather system going. Newspaper and kindling or a diesel rag. A little cold diesel smoke in the kithen will make every old truckdriver feel comfy and wheel bearing in the early morning!

Get drafty

Motorsen

 

[4seasons]

I used to have the same problem. After one too many times of filling the house with smoke I finally figured out the trick to get the smoke going up the chimney FAST. My stove has a horizontal stove pipe out the back that goes thru the thimble. I wad up a full sheet of newspaper and stick it in this stovepipe. Then I load the stove with paper, cardboard, kindling, just like normal. Then I light the paper in the stovepipe and give it a few seconds to catch up. This piece of paper starts to preheat the chimney and get things flowing the right way before the paper is burned up. As soon as I hear a small roar I light the paper in the fire box. Almost instant draft.

This trick may not work on a vertical stove pipe as well but I bet you could modify it to work.

 

[mga]

Does barometric pressure have any thing to do with starting a fire?..........high or low pressure systems?
Every once in a great while it seems to be difficult to start a fire, once going it is ok. Just curious. We start the wood stove the same way every time, wood and kindling well seasoned......Hmmmm.

what kind of chimney/flue?

 

[blacklocst]

No issues with low pressure here last night, secondary tubes look like their ready to explode, had to choke down the air intake to the point where it was letting little air in and it was still blazing away. Any one else have this happen with their stoves last night? I'm thinking an unusually high pressure system could have been the culprit.

 

[Motorsen]

Barometric pressure have nothing to do with that. The pressure will be the same or at least allmost the same in and outdoor. If it should make a difference there should be a pressure difference. This would mean all of a sudden a high pressure sets in. In like barometric pressure rises from stormy low pressure to really nice weather high pressure in 2 minutes. Very likely to happen well not really uhh?
Hot air rises and cold air falls down. End of story. Allmost. Local obstructions, wind direction, etc. can ofcourse have an influence.
But blacklocst you maybe had a nice hot chimney last night? Hot chimney= good draft.

Motorsen

 

[chucker]

bar pressure along with any kind of humidity will always have something to do with starting a fire! unlike a high pressure system being warmer an dryer a fire will start faster an easier! wind is another element in natures way of hampering a fire to not burn away like a forest fire in wet woods..

 

[Motorsen]

Chucker I will advocate that you will have the same pressure inside as you have outside the house. Unless you have some sort of exhaust fan or similar running. When that is said I agree that local fenomenons outside like wind over a roof can produce a local high pressure on the windward side of the roof. Or a downward windstream on the leeward side pointing down a too low chimney.

 

[hupte]

well, you have to take into account the wind speed the higher the wind speed the more of a venturi effect you'll have in your chimney. basically when the wind blows it creates higher pressure as it blows over your house and lower air pressure inside of your house (comparatively). thus actually creating a vacuum and sucking the air out of the chimney like sucking up a drink thru a straw. which is why its easier to start a fire in a wood stove on a windy day. simply put- more wind= more draft.

but if there is no wind the the pressure inside your house should be the same as outside. or close to it.

 

[blacklocst]

Barometric pressure have nothing to do with that. The pressure will be the same or at least allmost the same in and outdoor. If it should make a difference there should be a pressure difference. This would mean all of a sudden a high pressure sets in. In like barometric pressure rises from stormy low pressure to really nice weather high pressure in 2 minutes. Very likely to happen well not really uhh?
Hot air rises and cold air falls down. End of story. Allmost. Local obstructions, wind direction, etc., can ofcourse have an influence.
But blacklocst you maybe had a nice hot chimney last night? Hot chimney= good draft.

Motorsen

Lit a fire in the morning and made one when I got home , just a few small coals left in the firebox. I don't think the reason was a hot or even warm chimney that caused the runaway fire I think the cold front that blew threw here was the culprit.

basically when the wind blows it creates higher pressure as it blows over your house and lower air pressure inside of your house (comparatively). thus actually creating a vacuum and sucking the air out of the chimney like sucking up a drink thru a straw. which is why its easier to start a fire in a wood stove on a windy day. simply put-more wind= more draft.

This is what I think happened with my stove last night or it could have been the 2 year seasoned Ash I was burning.

 

[woodchuck357]

I've had that problem, thought my stove pipe needed to be taller to create more draft, still didn't work. Seemed like the cold air was to "heavy" and the smoke wanted to come out the door instead of up the pipe. I actually opened the front door of the house and the fire started going. I still haven't figured out why

Really tight houses can make it difficult to get enough combustion air into the firebox. That is why running a duct from outside is sometimes necessary to get a stove or fireplace to work well. Opening a door or window a crack works but mixes the incoming air with with already heated air and isn't as efficent.

 

[tla100]

What woodchuck357 said. I had some trouble with it when I first installed wood burner in basement. I have old house but is really tight after new siding, 3/4" dow board under and new windows. Installed 4" fresh air supply to back of stove and have not had any issues since. I have only lit one fire this year, always have some embers in bottom. Stir up with homemade grate and throw 4-6 scrap 1"x1"x 16" pine, throw mix of split and smalls, leave stove door cracked 1" and go get ready for work. 10 minutes later, go down, shut door and have fire rolling. I get scraps from local pallet maker that has tubs outside, 1st come 1st serve. It is amazing how fast it really gets going.