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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?
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.
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.
Janett
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 > [HYPERLINK@www.woodstove.com] .. may prove helpful for the both of you ...
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.
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 >
Quoted:
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.
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.
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
..no 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!
