Help With Exterior Chimney, Draft on Cold Days

[Fire93Medic]

I bought my house from my grandparents and they have had this chimney setup for 30-40 years. I have a walkout basement and the pipe goes through the foundation at about 4' off the floor and then up well past the roof. It is 7" pipe that I have adapted to 6" inside. The brand pipe is Amerivent I think.

On cold days it is very difficult to get a draft. If you take the pipe off and place your hand there you would think there is a fan blowing down. I had the stove hooked up to the masonry chimney for awhile and just moved it back yesterday due to finishing the basement and wanting the stove on that side.

Last night I had the stove going great and about 10pm I dampened it down nice and went to bed, this morning there were still hot coals in the bottom, the stove was warm, stove pipe ice cold, and I could feel the reverse draft and I had CO in the house.

The chimney is clean, the top of the chimney is 2' higher than anything within 10'. Back in the day my father even said they raised it even more with no luck. I was told this was a "cold plug" and it just because of the exterior chimney, but I read here other people with these chimneys without issues. I was thinking on buying the "Tjernlund AD-1 Auto Draft Stove Blower" but hate to spend $150 to still have a problem.

The stove is an Englander with the pipe coming from the top, the old stove was a rear discharge with the same issues.

Sorry for the lengthy post, I am looking forward to getting this fixed!

 

[Simonkenton]

I had a setup like that for 15 years and didn't have a problem. My pipe went up 3 feet from the stove, took a 90 and went through the wall, then another 90 and went up about 18 feet.
My pipe was double wall insulated stainless steel pipe, 6 inch, I bought it at Lowe's.

Is your exterior pipe insulated double wall?

 

[jatoxico]

What you have is called the stack effect (that's your search term) and it sounds like you have just about every negative contributor in place. Stack effect can occur in any multi-level install and occurs because warm air rises and escapes the building envelope so the house itself is acting like a chimney. The negative pressure left in the dwelling needs to be replaced and the chimney becomes the source for the needed air.

Basement install, cold exterior chimney, old leaky house and other less common factors are all contributors. If you have any grossly leaking penetrations to the attic such as a pull-down stair it may help to seal it. Otherwise giving the house another source of air like opening a window in the basement may help but that does kinda defeat the purpose of running the stove I know.

This can be a difficult issue to solve. One fairly sure-fire fix would be to put the stove higher in the house closer to the neutral pressure plane.

 

[double-d]

You mentioned the Auto-Draft fan as a potential solution, there is also the "Draw Collar" that solves the problems of drafts and smoking wood burning stoves, by creating draw before you even light a fire. Just plug it in and an electric coil heats up the flue and establishes a draft. It is a small section of black stove pipe that you place in line with your other stove pipe.

 

[WoodyIsGoody]

You mentioned the Auto-Draft fan as a potential solution, there is also the "Draw Collar" that solves the problems of drafts and smoking wood burning stoves, by creating draw before you even light a fire. Just plug it in and an electric coil heats up the flue and establishes a draft. It is a small section of black stove pipe that you place in line with your other stove pipe.

How will that solve the OP's problem of backdraft as the fire begins to coal?

 

[Fire93Medic]

Thanks for the replies. I did try opening a door to get the stove going and not a ton of luck. I have an insert upstairs in the fireplace and that gives me no problems at all. I think he pipe is non-insulated triple wall but not sure. I am not thrilled about the idea of the electric coil or leaving something open because I am more concerned about when the stove dies down the CO and fumes back into the house, and leaving the electric coil on or window open does not seem the most economical. I might look into that fan where I can turn it on when I start the stove and again when I go to bed unless someone has experience to tell me otherwise. The point of this stove is to keep the finished basement warm and moving it upstairs wouldn't do the trick.

The house is a 1000 square foot ranch, I have actually sealed it up as tight as it can be over the years, pull down stairs sealed, Mass Save came in and sealed the attic and blown in insulation, new windows, new siding with 1" foam under with taped seams and half the basement is finished and insulated exterior walls. Not much more I can do there. Below are photos of the setup, I know the glass in the stove is broke, did that the other day!

 

[coaly]

Do you have a radon fan extracting air from the basement, or any other mechanical fan like a power vent on a water heater? What other heat sources are vented or using another chimney, like a furnace or boiler? Unvented propane heaters or other oxygen using appliances?
How many floors above basement? Does the stove in basement only heat basement level or are there openings or fans moving the heat upstairs?
A quick walk through shows these things as well as dust in the cracks of attic doors or hatches showing a major air leak.

 

[Fire93Medic]

No radon fans, water heater is electric, electric dryer vented outside but no different when that is running or not, gas forced hot air furnace is direct vent with its intake piped outside. 2 bathroom fans but both are almost always off.

1 floor above basement, attic is sealed tight. I leave the door to the basement open to get some heat upstairs but close it at night (just incase of a fire in the basement, a shut interior door can make a huge difference!). No fans running. This chimney has been an issue from before I existed, so none of the renovations have made it worse. My biggest concern is the CO issue when the stove cools, I can deal with the starting problem. The reality is that this house was probably full of carbon monoxide all the time, but my grandparents never had a CO detector!

My father and I were thinking on boxing the chimney in and insulating it, but not sure this would even make a difference since it is an unheated space except for the heat of the chimney itself.

 

[bholler]

is the chimney insulated or is it air cooled pipe?

 

[Simonkenton]

As I was saying above, my install was nearly identical to yours and it worked fine. But, my stove was not in the basement it was on the main floor, and, my pipe was double wall stainless steel insulated, 6 inch. This was on a nice little Waterford wood stove.

 

[double-d]

How will that solve the OP's problem of backdraft as the fire begins to coal?

Maybe solution, is the incorrect terminology if that is what you are referring to, I was only suggesting an additional option to the Auto Draft fan, as a source to help "create an upward draft", that can help stop the flow of cold air and smoke. The Draw Collar supplies the hot air and rises pushing the air upward. The Draw Collar can operate continuously 24/7 if needed. Both these devices will help, but theses may not a solution to the overall problem.

 

[Fire93Medic]

is the chimney insulated or is it air cooled pipe?

I believe it is air cooled triple wall. I looked up Ameri-Vents site and they have both, but my father said he is pretty sure it is air cooled. The chimney is at least 40 years old but looks identical to the current versions online.

 

[coaly]

bholler gets the prize again. That picture tells a lot. He see's one and grabs the screw gun !
The two types today will be "pack" which is 1 inch thick densely packed double wall (6 inch ID will be 8 inch OD) or triple wall which has a thin insulation wrap around the inner liner and appear the same size as your outer pipe.

 

[bholler]

Yeah if it is air cooled that is probably the problem. They cool much much quicker than insulated chimneys. The air cooling works great for protecting the house but does not work well performance wise.

 

[WoodyIsGoody]

Maybe solution, is the incorrect terminology if that is what you are referring to, I was only suggesting an additional option to the Auto Draft fan, as a source to help "create an upward draft", that can help stop the flow of cold air and smoke. The Draw Collar supplies the hot air and rises pushing the air upward. The Draw Collar can operate continuously 24/7 if needed. Both these devices will help, but theses may not a solution to the overall problem.

I hear you but I guess I just don't consider throwing expensive electrical heat away (up the chimney) as a solution when the entire point of burning wood is to avoid using expensive (and un-environmental) electric (or oil, propane, etc.). It would be like charging your electric car with a gas generator, makes no sense.

 

[double-d]

I hear you but I guess I just don't consider throwing expensive electrical heat away (up the chimney) as a solution when the entire point of burning wood is to avoid using expensive (and un-environmental) electric (or oil, propane, etc.). It would be like charging your electric car with a gas generator, makes no sense.

I do see your point, but the OP said he was going to leave a fan on at night, and had considered the Auto Draft fan, both would be using more electricity than a draw collar, but it is still a waste of energy, I understand that, and the point you are making.

 

[bholler]

I do see your point, but the OP said he was going to leave a fan on at night, and had considered the Auto Draft fan, both would be using more electricity than a draw collar, but it is still a waste of energy, I understand that, and the point you are making.

I really strongly feel that both the fan and the draft collar are just bandaids that will possibly just cover up the real problem. I would say to fix it the chimney needs replaced.

 

[jatoxico]

I had the stove hooked up to the masonry chimney for awhile and just moved it back yesterday due to finishing the basement and wanting the stove on that side.

Did you have down drafting with the masonry chimney and is that chimney on an inside or outside wall?

 

[jatoxico]

So here's my thinking; If the masonry chimney is also in the basement and on an outside wall and did not downdraft then replacing the old metal chimney might work. If the masonry chimney is inside the house and penetrates at the top of the building replacing the old metal chimney may not do the trick since it still is completely outside. No doubt replacement would be better but total fix??

 

[bholler]

may not do the trick since it still is completely outside.

Yes but the current chimney is air cooled not insulated. They are totally different with an air cooled chimney performance wise it is pretty much the same as single wall pipe out there as your chimney. It is much safer yes but it offers no heat retention in the chimney at all. Even a plain old exterior masonry chimney would be much better.

 

[jatoxico]

Yes but the current chimney is air cooled not insulated. They are totally different with an air cooled chimney performance wise it is pretty much the same as single wall pipe out there as your chimney. It is much safer yes but it offers no heat retention in the chimney at all. Even a plain old exterior masonry chimney would be much better.

Right, I'm with you there which is why I'm curious about the placement and performance of the masonry one. If it's an exterior and was working I would have high hopes that replacing the old metal chimney would work. If it's an interior or was not working I would question the results after replacement.

 

[WoodyIsGoody]

I do see your point, but the OP said he was going to leave a fan on at night, and had considered the Auto Draft fan, both would be using more electricity than a draw collar, but it is still a waste of energy, I understand that, and the point you are making.

No. Electrically heated draw collars consume 450 watts. That's more than any reasonably sized fan for the same purpose.

Totally screwy idea.

 

[bholler]

If it's an interior or was not working I would question the results after replacement.

Agreed if it does not work either then I would suspect a negative pressure issue

 

[lukeg199]

Would love an update on this thread. I have a similar issue but it takes several days without a fire to cool off and reverse flow, so no CO issues. Just cold air. This year I was determined to do something about it and put rigid foam insulation on the bottom 8ft of the exterior chimney in addition to retrofitting a blast gate on the 3inch flange of the outside air adapter to fully choke any airflow when not in use. So far it is good but much colder days lay ahead...

 

[begreen]

This year I was determined to do something about it and put rigid foam insulation on the bottom 8ft of the exterior chimney

Can you explain this further? Foam insulation and chimneys don't usually go together.