First ever backdraft

[manooti]

Started to use the wood stove earlier this year as the boiler completely took a poop so running on wood as primary.
Under 50 degrees I get huge smoke in the house as I light it up. After everything gets hot the draft works. Then smoke spillage every time I open door to refill.
This didn’t happen before. New this year.
Have the us stove 2000.
24 inches up from stove to a 90.
3.5 or 4’ horizontal to wall thimble. Forgot how many 3 foot sections but either 15 or 18 feet exterior triple wall.
Gonna try to use 2-45s instead of that 90 but how low can I make that vertical run directly off the stove? I was aiming for 15 inches up to a 45 then to the other 45 to shorten the horizontal run and eliminate the 90. The shorter I can make that vertical run the shorter the horizontal run. Dry fitting looks like I can cut 2 feet off horizontal if I can get under 15” vertical from stove.

 

[Microduck17]

I don't know about the 45's but I can tell you that getting a draft at warmer outside temps is difficult especially if the wind is hitting the house on the same side the chimney exits. I open a window on the ground floor on the windward side of the house to equalize the pressure, that helps with startup draft.

If your spark arrestor screen is partly clogged that will cause draft issues. Also check the cap for birds nests if you dont have a screen.

I use an electric heater or hair dryer to pre heat the pipe if it is over 40 degrees outside. I stick it in the stove pointed at the pipe outlet and leave it run for 5 or 10 minutes then remove it fron the stove and burn a big ball of loose paper to further preheat things. Hopefully someone who knows about your particular stove will chime in and answer your question about the elbows.

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[manooti]

Thanks for the info. I tried most of that. In the end I just let a propane torch sit on stove aiming at pipe and let it warm up.
Took everything out. Redoing the pipe. 2 adjustable 45s with a 15 inch rise from stove. Second 45 at the thimble so it pretty much eliminated a 2 foot horizontal run. Has a 13 inch section of pipe between the 45s.
It “looks” like it’ll help but idk.
I guess my next best option is to go straight up through roof but that’s over my head and one estimate I got was 2800 just for labor lol. I was like “ok”. Lol. Chest still palpitating just thinking about it.

 

[Microduck17]

I hope you don't have to go the through the roof route. If it worked last year it should work this year.

Are all the air inlets on the stove clean and un-obstructed?
Is the wood dry?
Is there a new appliance in the house that could be pulling a vacuum on the house by pumping air outside?
Did you seal anything off over the summer?
Power vent water heater?
New windows or doors?
Attic vent fan running?
Do you have a radon mitigation system?

If there are trees close to the house and they still have leaves that could make a diffrence in the airflow near the house.

Just brainstorming here, sometimes the problem comes from an unexpected source.

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[kennyp2339]

Temps in PA have only dipped into the 30's a few times so far this year, the majority of the time its been just in the 40's at night 50's / 60's during the day, natural daft is weak this time of year and will improve as temps get colder and more stable, also with the stormy conditions low pressure systems effect draft to by slowing things down a little and with marginal conditions it could create or exacerbate the smoke spillage.
Trading out the 90 deg elbow for (2) 45's is a great idea, it will help improve flow by decreasing the turbulence the air creates by going hard up (think buzz saw effect)
If the chimney has been cleaned and you are sure there are no restrictions in the chimney or cap, check and make sure the baffle board in the stove is pushed all the way to the rear of the stove.

 

[vanubee]

Temps in PA have only dipped into the 30's a few times so far this year, the majority of the time its been just in the 40's at night 50's / 60's during the day, natural daft is weak this time of year and will improve as temps get colder and more stable, also with the stormy conditions low pressure systems effect draft to by slowing things down a little and with marginal conditions it could create or exacerbate the smoke spillage.
Trading out the 90 deg elbow for (2) 45's is a great idea, it will help improve flow by decreasing the turbulence the air creates by going hard up (think buzz saw effect)
If the chimney has been cleaned and you are sure there are no restrictions in the chimney or cap, check and make sure the baffle board in the stove is pushed all the way to the rear of the stove.

Piggybacking on the baffle board tip - make sure the ceramic insulation (if there is one) on top of the baffle board is also pushed back. I have a US stove/Vogelzang. I ordered a replacement insulation blanket from the manufacturer a couple of years ago. Installed it and fired up the stove and filled up the entire house with smoke. Turns out that the ceramic insulation blanket wasn't cut properly and was obstructing flow into the chimney.

 

[xman23]

That's a classic plugged cap screen story.

 

[manooti]

Everyone has awesome tips. Thank you.

still leaves on trees here. Rain all day and most of them coming down but not completely. Didn’t seal anything. Nothing really changed except the boiler. I have the tool that wires in on the valves or zones to circulate the water. Forgot the name of it. The boiler stopped working so there is literally no heat in house except from stove.

only thing I can think of is the residual heat from baseboards when it worked helped with draft. I’m also 2000 ft above sea level. I read on one of the other stove manufacturers manual that elevation requires more height?

just finished the 45 install. It looks so butchered. I can never do stove pipe right. Cleaned the chimney and yeah I’ll admit I did get caked with some fine chocolate powder.

I’m also running hot sticks kiln dried wood and throw in some regular cord wood. A neighbor gave me some wood and it sounded hollow but the dark wood released some sizzling liquid. Wasn’t a lot of that stuff used because I mainly use the hot sticks stuff. Tomorrow gonna be cold low 30s so crossing fingers

 

[manooti]

The clean chimney brought it back the way I remember it. The 2 45 elbows replacing the 90 made a huge difference as well. Seems like I have more control over fire and maintains flame and barely any smoke.

my wife is planning on me doing the weather sealing on windows lol. Is that going to screw with draft too? windows on second floor. Stove on 1st but facing the stairs.

 

[Microduck17]

A clean pipe makes all the difference sometimes. Think of your home as a closed container the stove and chimney pull air out of your home and it is replaced by air that leaks in through gaps around doors and windows and other openings. One way to get back draft is to have your home sealed up so tight that the air your stove is pulling out can't be replaced quickly enough by the leaks to equalize the inside and outside air pressure. When this imbalance gets to a point where the draft on the chimney cannot keep lowering the pressure in the house any more then the flow of air (and smoke) up the chimney is reversed as the pressure tries to equlize. Kind of like a bottle will glug when poured too fast. Normally a house will have enough air leaks to balance the draft of a stove. If opening a window immediately stops the back draft then it would indicate that you need to let some air into the house. Cracking a basement or ground floor window is usually all that's needed.

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