Everything's cooling down

As others have said - Negative Pressure. My install is similar to yours, and we had this problem for the first 2 seasons. It would only happen when the barometric pressure was low (during rain/snow) it was annoying, and aggravating! The first, and cheapest solution worked for us Vacu-Stack!

Adding another piece of pipe will increase draft, which should give a greater pull. Why not start there?

Cta2885 said:

I really am lost at what to do, weather an oak for my furnace or whatever would help? I do not know

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You have too many appliances removing inside air at the same time. You really need and OAK for your wood stove. Your gas furnace is already creating a vacuum in your house that is pulling its feed air down the flue for the wood stove. YOU may need an OAK for the gas stove as well.

Cta2885 said:

Ok, so all these posts about an oak. I do not have anywhere on my stove to hook one up, what should I do then?

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All my my EPA stoves do.

Cta just trying to understand if this is a constant or ocassional problem. If you turn off your furnace, dryer and everything else that could compete for or create negative pressure condition do you still get cold air coming down the chimney? If so I don't see what an OAK will do for you. If it is an occasional problem then maybe.

From your original post sounds like you need to correct your draft. Straightening the pipe ought to help and adding height or warming the stack are other options.

Cta2885 said:

Stove is a us stove co. Aps1100

My issue is related with what I assume is downdraft. My stove pipes are cooling down to the point where at night my stove will start puffing, with smoldering half burnt logs still going. My worry is I have two kids in the house and don't want anything to happen. Once I put paper in my clean out and light it I can start the fire inside the stove it self. I've tried heating up my single wall inside with propane torch, blow dryer etc. but nothing works it will all still blow out the stove. As well as opening a window still doesn't work.


I have cut off power to boiler, range hood and dryer all while trying to start and nothing is different.


For some reason I don't feel as if my words are making sense I'm sorry

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You're making sense. If your having problems on standby you gotta figure out how to improve draft using more pipe, heat source, cap change or combo of all three.

Cta2885 said:

Stove is a us stove co. Aps1100

For some reason I don't feel as if my words are making sense I'm sorry

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The issue is ,what is causing the downdraft? I still think your gas furnace is creating it. Your house may be fairly tightly constructed ,so your gas furnace will pull air from the least restrictive source,which now happens to be a cold flue on your woodstove. Other things that cause negative draft are....
besides the home fuel burning furnace.............
1. Clothes dryers
2. Range hoods vented outside
3. Bathroom vent fans

Any one or a combination of these can cause your stoves flue to downdraft when it gets cold.

AN example of what i am saying:
Once tried to run my woodstove and my coal boiler at the same time. The wood stove created such a strong negative vacuum in the room ,that it pulled air down the flue of the coal stove which was idling on low and still running,causing the coal boiler to BURN BACKWARD INTO THE HOPPER almost causing a fire.

jatoxico said:

You're making sense. If your having problems on standby you gotta figure out how to improve draft using more pipe, heat source, cap change or combo of all three.

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Improving draft without adding an OAK will only starve the gas furnace IMO, which need x Cuft amount of air as well. IF you are running 2 high draw appliances at the same time you really do need a separate source of combustion air .other than what the appliances can pull thru small holes in your homes exterior and around doors and windows.

Cta2885 said:

I have cut off power to boiler, range hood and dryer all while trying to start and nothing is different. For some reason I don't feel as if my words are making sense I'm sorry

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Hear ya loud and clear! Is this a newer house that is pretty airtight? How high is it in relation to the roof line? Are the furnace, bath and kitchen exhausts higher than the chimney? Hard to say without some better pics. Are you in a windy spot, and on the leeward side of the winds?

Here's a good diagram by another forum member relating to my own former troubles -


As has been suggested, try going up another 3ft with the stack, a different cap (vacu-stack, etc) or a heated pipe.

Seasoned Oak said:

The issue is ,what is causing the downdraft? I still think your gas furnace is creating it. Your house may be fairly tightly constructed ,so your gas furnace will pull air from the least restrictive source,which now happens to be a cold flue on your woodstove. Other things that cause negative draft are....
besides the home fuel burning furnace.............
1. Clothes dryers
2. Range hoods vented outside
3. Bathroom vent fans

Any one or a combination of these can cause your stoves flue to downdraft when it gets cold.

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What about a leak in the chimney itself? In an early post there was mention of water at the clean out at the base when he opened it to light a paper fire there. could it be a simple air leak someplace maybe at the base of the outside of the chimney?

Seasoned Oak said:

Improving draft without adding an OAK will only starve the gas furnace IMO, which need x Cuft amount of air as well. IF you are running 2 high draw appliances at the same time you really do need a separate source of combustion air .other than what the appliances can pull thru small holes in your homes exterior and around doors and windows.

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Seasoned, believe me I'm not saying you don't have a point but if the chimney is down drafting w/ the furnace and everything else off don't you have to correct that first? If it was drafting (even poorly) and the furnace coming on caused a problem then the OAK might fix it. Am I crazy?

Cta2885 said:

Stove is a us stove co. Aps1100

My issue is related with what I assume is downdraft. My stove pipes are cooling down to the point where at night my stove will start puffing, with smoldering half burnt logs still going. My worry is I have two kids in the house and don't want anything to happen. Once I put paper in my clean out and light it I can start the fire inside the stove it self. I've tried heating up my single wall inside with propane torch, blow dryer etc. but nothing works it will all still blow out the stove. As well as opening a window still doesn't work.


I have cut off power to boiler, range hood and dryer all while trying to start and nothing is different.


For some reason I don't feel as if my words are making sense I'm sorry

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Cta, Just another point for clarity, your chimney should draft at least a little even when cold.

Fireshoppe said:

Draft is achieved by hot air rising through the chimney pipe. Your chimney is and air cooled insulated hybrid that should not be used in your application because it will not hold heat inside the flue pipe very well. The fire in the stove has a natural cycle; high flames as the wood catches and begins to burn off the water; high heat output stage where the energy is converted into gasses and burned in the stove; charcoal which provides intense heat at first then begins to tail off.

You have to burn paper in your flue to begin the draft cycle. The heat from stage 1 and 2 maintain flue temps but as stage 3 starts to tail off your air cooled flue does what it is supposed to do (but what is not desired) and cannot sustain the draft because of too much heat loss in your exterior installation. So you need to supplement the heat loss and the Draw Collar is made to do just that. To start a fire you turn on the collar, it heats the stove pipe causing a draft to start. When the fire starts to tail off the Collar senses the low heat and turns back on increasing draft.

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Maybe it's semantics, but I thought draft was the result of the temperature difference from the top of the chimney to the chimney inlet?

I don't know much about drafting but I hope this might make some sense. I have a tall chimney, 6' pipe but mine is in a chase. I get draft even in very cold weather on a frozen chimney. I do have all primary and secondary air coming into the insert from the outside. If the chimney has a down draft issue doesn't that mean something is pulling air down it? If so, what? Do you have the ability to bring air into the stove from the outside? My chimney peak is about 3' above the roof peak.

Cta2885 said:

When my stove is down for cleaning and everything has cooled, I can put a lighter in, light it, and the draft blows out the lighter.

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That ain't good, add a section of pipe.

1) Haven't seen anybody mention it yet, but: where there is smoke, there is carbon monoxide and where there is no smoke, there may still be carbon monoxide. So BE EXTREMELY CAREFUL. If the draft is reversing - especially while you're asleep, it can fill the house with smoke if the logs are still burning, but if you're down to the coal stage, it can be odorless carbon monoxide.

2) Exterior chimney's aren't ideal, but there sure are a bunch of them in use - successfully. So it would seem there must be other factors aggravating the situation.

3) This clean out you mention, and all other joints need to seal AIRTIGHT. Any leak you have at a wall thimble, clean out, joint or other point in the chimney will pull in fresh, cold air - which means it's not pulling smoke out of the stove.

4) You say this is a brand new stove/chimney? (assuming this problem has existed from the very beginning) Is there any chance shipping material was left in any of the pipes or stove itself? Or is there any chance anything in the baffle area of the stove has shifted and partially blocking the flue? Sometimes there can be a fiber blanket above the baffle which might shift, and if I had a nickel for every time I've seen a cubby hole at a job site or store stuffed with trash, I'd have a pretty nice retirement!

5) If the stove used to work and has suddenly developed this issue, it's a whole different story.

6) There is at least one other flue in the picture, so guessing some other combustion appliance? It might be good to take stock of everything pulling air out of the house. Any one thing may not take a lot, but when you start adding up things like boilers, furnaces, water heaters, bath fans, stove hoods, etc it can pull out quite a bit of air. Also consider things like attic fans or attic openings which can let hot air rise out of the house and pull a 'vacuum' on the remainder of the house.

I believe he is using this.