Requesting help solving a down-draft problem for a basement stove with a three-story chimney

[toastable]

We moved into a new (to us) home last November. It is a two-story dwelling with a basement, so three stories total. The home has a wood-burning stove in the basement and a fireplace insert on the first floor, each with its own flue. We had a chimney inspector come out who gave us the thumbs up after installing missing chimney caps. (The house had sat unoccupied for a while.) The fireplace insert on the first floor has no problems and we enjoyed several comfortable wood fires last winter. The basement stove, however, has a pretty bad downdraft that I was not able to solve last year. I put it aside for a while in favor of more urgent repairs but I decided to take it up again earlier this month when the weather started to turn.

The stove itself appears to be a late-70s / early 80s Glacier Bay stove, based on some image searches and the age of the house:

The smoke outlet is 8". It rises approximately 3 feet and then turns 90 degrees to into the flue and connects via ceramic collar. The ash clean outs for both flues are located on the other side of the chimney.

The basement is about 8'6", sunk into ground to a depth of approximately 6-7' (the house sits on a slope). There is a walk-up / walk-out staircase with large heavy door inside the basement and a storm-cellar-style door covering the basement stairs. The interior staircase has a door at the top of the stairwell that leads to the first floor. There are five small windows (about 2'x3") that used to open but have pretty much rusted shut.

The original pipe leaked smoke at the elbow joints so I replaced the entire pipe assembly, assuming there were probably other pinholes that I just could see. I copied the same design but I did add a collar connector that the previous owner didn't have in his set-up. (Yes, the metal cutting is ugly and assembly are ugly, I'm aware.)

For the life of me, I cannot figure out a way to beat the downdraft. No combination of open/closed house doors, open-closed stove doors, or open/closed vents seems to get the smoke up the chimney. When burning newspaper torches in the stovepipe, I see smoke seeping back into the basement from where the stove connects to the ceramic. I don't get smoke coming from the flue clean-out (right-hand door) unless I close both doors and both airvents on the stove. Out of curiosity, I burned newspaper in the ash clean out to try heating the flue liner, but the smoke came back down the stove pipe and exited either via the stove doors, stove vents or the ceramic collar.

I know the stove was used based on the inside of the old pipe and I doubt the owners just smoked up the basement each time they lit the stove. As best I can tell from the documentation the previous owners left behind, the HVAC was added after the original house was built so I'm wondering if the duct work changed something about the airflow in the house such that the stove no longer works properly.

I'm flummoxed. Any ideas?

 

[begreen]

Is the stove venting into a cold exterior chimney? Is it into a clay tile liner or a stainless liner? Does it behave better once the stovepipe and chimney have warmed up?

Basements can be fussy for draft. This article explains what is happening.

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The first place to look is upstairs. Leaks up there can cause a chimney effect, sucking air from below in the basement. Are there any leaky windows or attic door, or upstairs hallway vents to the attic area that can be sealed? Another issue can be exhaust fans in the kitchen, bathrooms, clothes dryer, and radon exhaust fans. Also, seal up the ash cleanout doors by running a bead of silicone adhesive around the rim and then closing it, and letting it set up.