Help!...smoke is backing into my house

Santa Rosa, CA

I am looking for some help.

I get a situation occasionally (like last night) where I fire up the cold wood stove and smoke pours back into the house as if the chimney is blocked.

I have a 10 year old Lopi Liberty stove that works great. We burn fires nearly every night here in northern California. A couple times a year it seems the chimney is working backwards, where cold air in the stovepipe prevents smoke from rising. Smoke comes out from the stove air vent and into the house. Of course as the cold air "plug" is pushed out the stovepipe and corrects the flow, everything works as it should but by then, my house is full of smoke.

How common is this? 99 out of 100 times, there is no problem and I get normal flow up the stovepipe. It is that 1% that fills my house with smoke. How do I know when it will happen? How do I prevent it?

Any suggestions?

So.App.Mtns., United States(Zone 5b)

Good question, and I await an answer also. Mine only backs smoke into the house if it is very windy.

So.App.Mtns., United States(Zone 5b)

Found this..

Always make sure that your chimney is drafting upward before you start your stove. Some chimneys have a tendency to reverse while not in use. In most cases the following procedure will start the chimney :
Place a small piece of newspaper as far up in your stove or chimney as possible and light it. When it burns and gets pulled up the chimney-then light the fire.

Gamleby, Sweden(Zone 7a)

Darius, you could buy a chimney cowl that would take care of the problem for you. There are lots of different kind on the market, check on ebay too.
Sonoman. do you have the door fully, half or closed when you start the fire and how much firewood do you start with. Try to just burn little paper for a couple of minutes and just open the door a TINY TINY bit so the chimney have time to get the air heated.

NW Qtr, AR(Zone 6a)

Most times .. making sure that the top of your stove pipe extends beyond (above) the ridge of the roof, is most helpful.

Is your chimney/stove pipe flue (of the wood heater) shared with some other 'venting' appliance (water heater, etc)? Can cause problems, for sure - and some mitey serious problems!

Also .. some wood heaters have catalytic elements that may be a factor - ie: need cleaning and/or replacement.

The info, HERE > Cures for Backpuffing > .. may prove helpful for the both of you ...

- Magpye

Santa Rosa, CA

Thanks for the replies

From Janett: "Sonoman. do you have the door fully, half or closed when you start the fire and how much firewood do you start with. Try to just burn little paper for a couple of minutes and just open the door a TINY TINY bit so the chimney have time to get the air heated."

A: I typically start the fire with 4 pieces of wood, 2 pieces of branchwood (3-4" dia) going away from the air vent (perpendicular to the vent and door) to allow air to circulate and two very dry pieces sitting cross-ways on top (parallel to the door). I put newspaper between the two bottom pieces to light the top pieces. When the fire "takes", I add some more wood on top. Usually works--one match and I am in business. I usually start the fire with the door cracked--maybe a half inch to an inch--to let more air in than the vent allows. When the fire starts, I shut the door and regulate air through the vent. Usually, there is enough positive airflow to suck it up the chimney.

Magpye: There is a catalytic element on this stove, but there is a bypass for starting the fire. The bypass was open last night, so I don't think that was the problem. The stovepipe is not shared with anything else and the chimney extends above the roof line. It is a little below the highest point, but that point is some distance away. I'll try adding an extender. Thank you for the link on backpuffing--I will check it out.

Thanks again for the suggestions--I have some things to try.

NW Qtr, AR(Zone 6a)

Here's more ...

If you experience occasional downdrafting, opening a door or window for a few minutes to change the neutral pressure plane .. will help prevent a room/house filling with smoke.
The first two suggestions are simple ways to test if you have negative air pressure before lighting your fire .. and the third, is the solution to eliminating the problem.

1) hold your hand inside the fire box and up near the damper (make sure the damper is open) and see if you feel cold air coming down the chimney.

2) Light a good size sheet of paper and hold it in that same position up near the damper; if the fire goes out or the flames are being blown back the stack effect is happening.

3) Open a window or door to balance the air pressure in the room; light another piece of paper and hold it in the fire box the flames should draw up the chimney if the pressure has been equalized (leave the window or door open until you determine that a good draw has been establised in the chimney)

And .. jes in case >
Fuel-burning appliances are exhaust ventilators, as are kitchen and bathroom fans, clothes dryers, and central vacuum systems. All draw air from the house and exhaust it outside. When an exhaust ventilator operates in a well-sealed house, it may not get all the air it needs to function properly. When two or more exhaust ventilators operate at once, they may compete with each other for available air. In a competition for air, mechanical systems usually win out over natural draft systems.

The operation of a clothes dryer or high-volume kitchen exhaust can cause backdrafting of a fireplace or other woodburning system. In theory, all exhaust ventilators should be supplied with ducted sources of outdoor air. However, the many complications involved make the complete isolation of all ventilators very rare.

Exhaust ventilators operating on natural draft cannot usually compete with mechanically-powered ventilators. The chimney serving a wood stove may backdraft when the negative pressure produced by mechanical ventilators overcomes chimney draft.

- Magpye

So.App.Mtns., United States(Zone 5b)

Jannet, I had a cowl on the woodstove at my old place. I like the ones that rotate with the wind direction.

I'm getting ready to install a woodstove here and you can be sure it will all be done to Code, or better.

Lebanon, PA

I had that prblem with my pot belly stove got a down draft
a chimney cap worked very good for me

and also make sure your chimney is 2 to 3 feet higher than any part of your house

Lynn, MA

when that happens to me i just open a window for a few minuets and all is good

Gladwin, MI(Zone 5a)

There is good advice here. We found these things out through trial and error.
The paper burning to warm the pipe, the door open slightly to add air, etc.
When the wind puffs down the pipe (really, really windy days) I have found that lighting a candle or two really helps get rid of the smoke fast.
I know this is an older thread, but some may still be having this problem.

Cascade Mtns, WA(Zone 6a)

We have had a woodstove for over 30 years.
They only time we have problems with smoke backing into the house are...
1) windy day solution just close the door and hope for the best. It usually corrects itself.

2) fairly warm day... not enough differetial in the outside vs inside temp
to create a decent draft.
Solution is to create a hot fire faster... more small kindling, or even kerosene
will create a hotter fire to start the draft moving in the right direction.

3)plugged fire screen on chimney cap.
Solution... UGH clean it all!

Hillside Lake, NY

We NOW only get backdraft when it's windy outside; we no longer get it when we light and we rarely use newspaper (although I prefer a little when I light it, but I don't always have it and it's become unnecessary; criss cross some small kindling and maybe 1-2 pieces of larger wood (all should be dry/seasoned) - A PROPANE TORCH DOES THE TRICK WITHOUT THE SMOKE BACKING UP...just use it on the kindling- right then left side or visa versa - even center - til it catches good!

Greeley, KS

I am new so not sure this is the correct place, or if it is to "old" to be answered...but we have a two year old catalytic stove that is letting smoke roll out the door when filling, instead of going up & out the chimney...
The pipe is clean & clear.....Shall I just use the suggestions above to open a door/window to change the draft? VERY frustrating as it is letting quite a bit of soot settle in the house UGH!!
Any advise would be appreciated.
Thank you!!

Durhamville, NY(Zone 5b)

Not too old too answer. The thread comes to the top and hopefully someone will answer.

It's not just the chimney that needs to be free, but the catalytic unit also. Lots of things can happen to them.

Operating suggestions that I have.

If it's an option open the bypass around the catalyst for a couple of minutes before you open the door.

Open the draft and get the fire burning harder before you open the door. This heats the chimney more thus producing more draft to pull the smoke up the chimney.

Just crack the door open a half to one inch until the smoke starts to draw into the stove. The reasons from apply as well here..

Load the stove after the wood that is in it has burned down more. Sometimes this is all that it takes.

Your wood may be too wet and or green to burn easily.

Your chimney may just not have enough draft. Too small, too short, or mislocated are all possibilities. Too many bends is another.

Some stoves are just plain designed poorly and there isn't much you can do about that.

Gladwin, MI(Zone 5a)

This happened to us recently and the draft was partially gummed up.

ashford, United Kingdom

Simple way to stop wasting your time with little fires and quirks of you get your fire going... simple rule 1. If its around 0 or below use a hairdryer for about 30 sec or 1 minute.

this simply pushes hot air up warming the air as it goes, stops the stacking effect of a cold gas and you can start your fire as normal.

Stop wasting time trying to find out how you can light a small fire to move a big plug of cold air..... 2 tigs!! does not give off enough heat to move the cold Colum of air in your flue ( most people)... it might work for some and not others but to stop messing around and gassing everyone out for the night just open your front it cold..... oh! yes, then plug in the cheap hairdryer you bought from Argos for 10 blast the flue for 1 minute and your ready to go..... open the door slightly and blast it....... ALWAYS CLEAN you fire out please note you do not have to blast it on full to get it to work so please try it at the lowest setting first , it will cut down on ash being blown about...

try it tell it does not work. :-)

on warmer days it will be harder to start a good draft. I add more paper and small shards of wood as a bed and then gradually bigger pieces of wood when i need a stronger draft. I also light my fire using 2 pieces of center crimpted and flaired pieces of news paper placed inside my ash pan to increase innitial draft and prevent smoke coming out the opened fire box.
Also, if the wind is blowing just right and i open my door, the smoke from the freshly lit fire comes right in my house. And i have a lp furnace hooked to my wood stove and use the blower to increase airflow. the outside air intake to the lp will draw in some smoke from the outside if the direction of the wind is just right. this mostly happens in the spring where i live. its the price of using cheap heat.

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