Smoke reversion on cold starts

[DonTee]

Since the temps have been dropping the past few mornings I’ve had an issue with the stove workings backwards on start up. I assume it’s sucking air down the chimney because it’s smoking out the intake on the stove. It does this while trying to start the stove. Once the fire is going at all it straightens itself out and smokes starts coming out of the chimney again. This goes on for a couple minutes because it’s hard to keep the newspaper lit while this is happening.

Outside temps in the teens, and inside temp is in the 50’s. At the time of starting the woodstove is cold to the touch.

I’ve been using this stove setup since November without this issue. It usually starts just fine. I have just checked the chimney and stove pipe to make sure it’s clean, and it looks good.

Is there a way to preheat the flue without getting smoke in the house?

To be clear, I have no issues with the stove back puffing once it’s going unless it’s a very windy day. And even then it’s only when the wind changes directions a lot. I have the regular Dura vent cap on the chimney with a course screen.

 

[stoveliker]

Get a propane torch and use that a few minutes up the flue.

 

[DonTee]

Ok I have one of those.

Is this semi normal though for a cold stove on a cold day? It seems like if there was an issue with the setup it would have showed itself before now, when it was warmer out.

 

[DonTee]

Typically I would have the stove going 24/7 if I was staying inside overnight. But I let the stove die down before I leave the place at night. And don’t come back until the morning.

 

[kennyp2339]

Ok I have one of those.

Is this semi normal though for a cold stove on a cold day? It seems like if there was an issue with the setup it would have showed itself before now, when it was warmer out.

Depending on your house setup, negative drafts can be an issue due to house to property orientation, prevailing winds, stack effect, house tightness, open sill plates, ect.

 

[DonTee]

My chimney is on the back corner of the house, and typically the wind hits the house about head on.
The chimney is about 4’ feet above the roof where it’s at. I need to measure and see if it’s legal though, because I have an 8/12 roof and it might not be tall enough from the roof 10’ away. I do have another 3’ section of chimney I can add if I need to.

I’ve been working on tightening up the house. I actually have another thread going on about that right now.

 

[kennyp2339]

You might have an air foil / loop effect coming off the peak of the roof, height might be beneficial, just remember anything after 4ft needs a brace.

 

[Sailrmike]

My chimney is on the back corner of the house, and typically the wind hits the house about head on.
The chimney is about 4’ feet above the roof where it’s at. I need to measure and see if it’s legal though, because I have an 8/12 roof and it might not be tall enough from the roof 10’ away. I do have another 3’ section of chimney I can add if I need to.

I’ve been working on tightening up the house. I actually have another thread going on about that right now.

I have this issue too, and it got worse after replacing ext doors and windows. What I do on a cold start is I open a window near the stove about 4" open. Then I use a propane torch or hairdryer to get the draft going up from within the stove before lighting the fire. Hope this helps

 

[stoveliker]

Also,.with colder weather,.you might simply have a cold ""stack of air" sitting in your chimney. (Cold air collects at low points and can't get out, especially if the air outside has warmed up a tiny bit from when it cooled the air in the chimney.)
Open your stove and it'll stream out like water. Preheat it with the torch and it reverses before you make smoke with a fire

 

[DonTee]

I took off the stove pipe this morning to inspect the pipe and chimney. Once I had the pipe off it was shooting out cold air pretty good. So that makes sense then why it’s operating backwards until the flue is warmed up.

I’ve noticed the house is tight enough that when I turn the clothes dryer on it slows the woodstove way down. I can turn the air all the way up on it and it won’t get above 400 degrees. Once the dryer is off it goes back to normal 500-600 degrees.
I’m going to install an OAK as soon as I get all the parts for it.

When I have both the woodstove and dryer on if I open a window a pretty decent breeze comes in. And the woodstove operates better with the window open in that situation.

I have a heat gun that would probably work great for preheating the chimney. I hadn’t thought of that until you mentioned the hair dryer. I’ll try it tomorrow morning.

I just glanced up and it looks like I almost two complete sections of chimney above the roof. So just short of 6’. I did install braces about halfway up the last piece. With the winds we get here I didn’t want to take any chances.

 

[NorMi]

A heat gun is how I always started my wood furnace in the shop, since the building was always cold, there was no heat to send up the chimney to get any draft going. I attached a long steel tube that I put on one of the nozzles that came with the heat gun so I could start the fire through the ash door and leave the load door shut so there would be no means of escape for any smoke.

 

[Seanbear]

I had this same problem. I just bought a small space heater, and I sit it right at the door to the stove. The heater has a small blower in it, so it warms up the flue in about 5 to 10 mins. After that I have no cold air problems. I have also used a hair dryer.

 

[DonTee]

That’s also a good idea. I have one of those Stanley brand heaters that also has a blower. I could put that right in front of the stove doors.

 

[lml999]

As you make your house tighter, the problem gets worse, not better. You will either need to preheat your stove, as discussed above, or crack a nearby window, or both...

 

[Trevor Tahclep]

If my wife turns on the kitchen stove fan while I am removing ashes some of that ash comes back in to the room from the down draft, if the stove is cold and we turn on a bathroom or the kitchen stove fan cold air comes right down the chimney, I then need to open a window 5-6 inches to slowly reverse it. When I build a fire I start it up with lots and lots of dry kindling so the chimney heats up and draws quickly.

 

[10-cc]

May need a draft inducer or a Draw Collar

View attachment 289331

 

[10-cc]

look for Draw Collar

 

[Trevor Tahclep]

Now I simply ensure that no fan gets turned on until the stove temp reaches 250° - 300° which alleviates the downdraft problem. The wife knows no fan use when removing ash, she does not appreciate having to dust everything off a couple of times per week.

 

[DonTee]

I have the parts to build an OAK for my stove. I think that should help too. In regards to the house getting tighter.

I just need to get the piece that will mount on the outside of the house. And some kind of mesh to keep critters out.

Also this time of year I’m keeping the fire going all night more often. So the chimney is at least still warm in the morning.

I woke up to -8 degrees outside today. Weather said it was supposed to be 5 for the low. You know how that works.

 

[DonTee]

I’m copying the VC OAK with my own parts. This is part of the install sheet for my stove.