Question about draft.....

[dtabor]

I think this issue has to do with draft but you can correct me if Im wrong.....

I believe my draft is pretty good, I have a new Defiant NC installed just prior to this heating season, pipe comes out back for about 4 feet or so, 90* and straight up one piece SS liner close to 25'.

I have seen two issues that seem to contradict themselves. I have loaded up with a good bed of coals, charred/heated it all up to 650* plus and flipped the lever for the damper and the roar starts. After a bit I see that there is just a glow inside and every few seconds there will be a secondary type flame flare up. Sometimes when it does this, smoke wisps (sometimes puffs) out of the griddle area and sometimes around the doors. Gaskets are only a couple months old (new stove), door has been checked and tightened when needed.

Now comes issue #2. Load up for an overnight burn, packed to the gills with wood. Open it all up so its gets burning and up to temp. Came back a few minutes later to see if it was up to temp yet and notice that the stovetop temp isnt even up to 500* yet but the flame is being sucked into the stovepipe and causing that temp to fly off the handle, to the point I saw a glow on the pipe itself in just one little section of less than a foot. I dont have an internal stovepipe thermometer, just an older stovetop type that I set on the perpendicular section. It was way up there. It has never happened before but has happened 2x in the past 3 days. I flip the damper and it settles right down.

Are these issues due to draft or something else and am I doing something wrong that I should deal with? Neither of these things happens every burn.

D

 

[Hogwildz]

Could be wet wood, and 4' or Horizontal pipe before the 90? Sounds a bit much and must be pitched up a lil as heads towards the 90.

 

[dtabor]

Wood has been stacked since last winter so shouldnt be too wet.

Im guesstimating 4', might be a bit shorter. This was how the installers put it in. If they shouldnt have done this, I'll call them and have them make it right. I was trusting their knowledge as I dont have any on the install. My stove has the option of straight up or straight back out of the stove and my setup location only allowed for the straight back option. It is sitting in front of and going up thru an existing brick flue that used to be a fireplace (in the center of the house).

Just checked the manual, it shows the same setup as mine when going into an existing fireplace. Straight out to the 90 then up into chimney.

 

[Hogwildz]

Ok so its sitting in front of a fireplace and ran back into the existing chimney? I can see it needing the extra length then. From what I have read, it still should be pitched up slightly between the stove & the old chimney.
When the flames are being sucked up the pipe, is the air closed all the way or open or ?
It doesn't compute you have serious flames being sucked up the chimney yet the stove is staying kind of cool. Seems almost impossible to me. Where is the air set at when this is happening?
As far as the puffs, that don't sound good either, as you said in revers of the other problem, sounds like poor draft. Any chance the chimney might be partially clogged? Have you checked the caps for creosote buildup etc?

 

[Todd]

As far as the high pipe temps go, I think that is normal when in the bypass mode. All the heat gets sucked right up the flue. My stove has a bypass and if I don't watch the air my stack temps can peg out easily. Then if you shut down the air too fast and engage that could be causing the back puffing due to the pressure from gas and smoke buildup. Does that horizontal run have slight rise as it goes through the wall? 4' ft is about max for horizontal from what I have read.

 

[swestall]

HI, see you are still having some problems. The first item: It sounds like you are getting a pretty good secondary burn and the flames you see are the smoke/gasses igniting. I had this backpuffing problem on my VC also and I've heard of it on others. I could see the smoke coming from the griddle and one of the doors. I replaced the griddle gasket right away and that problem went away. I didn't replace the door gasket in the one place it is leaking and it still is leaking a bit. My symptom included the area around the leak getting white as well. So, you can have gaskets that seem to be good but are flattened out and leak.

The second problem is also not surprising. What happens when you load (the Defiant, Encore or other top loading stoves) up to the top, is that the wood provides a degree of heat sheilding to the griddle while the flame is actually sucked up in back of the wood to the stove pipe. You should go by the stovepipe temp under these conditions, this NC stove will fire off at 500 pretty easy. You do seem to have a pretty good draft. I have acutally had some luck in getting the secondary burner engaged at 300 on the stovepipe. The rumble on these stoves can be very loud or not so loud; no smoke out the stack is always a sign it is engaged.

 

[begreen]

Based on other owner comments I think that this may be a matter of getting used to the new stove. The new VC everburn stoves take a bit of extra finesse to get burning right. Symptom one appears to be backpuffing. This is caused when there is an excess of wood gas in the firebox and is suddenly ignites (the wisp of secondary). There are several ways this can happen. One might be adding new wood too early in the burn cycle, causing a massive increase in wood outgassing. But often this happens when closing off the air supply too quickly after new wood has been added. Leaks are another way, but it appears this has been checked.

The second issue sounds like strong draft. Has the temp outside dropped a lot recently? Is the wood being added at that time a different species or particularly dry?

 

[kevin fitzsimmons]

Is your defiant using the everburn system Ie diverting the flame path through the bottom of the stove at the back and trying to achieve secondary burn in the ceramic materials. If so, … you should search the posts for the everburn thread and add your issues to the ongoing list. I had a vc nc, and when it worked it worked very well, it was just very finicky and everything had to be just so. only problem was, I never really figured out what just so was. So, I bit the bullet and bough a set and forget it PE. Bye the way, I have very good draft and may even put in a inline damper.

 

[webbie]

dta, I think you may also have the problem of waiting too long to go into downdraft mode! Too many gases to burn. Please see:
https://www.hearth.com/econtent/index.php/wiki/flashback/

and the two threads referenced at the bottom of that article.

 

[dtabor]

Swestall, sounds like you've hit it again. I'll change the gasket on the griddle. Seems awful soon to have to do that though. Now that you mention it, there is a small white section about an inch long on the door gasket about midway down. I'll recheck it with the dollar to make sure. Maybe its just a matter of tightening the door latch?? Also looks true about the wood piling and blocking the heat from the top. I notice that daily that it is burning from bottom up and the temps dont start to go up very fast until the upper wood starts up. Im wondering if I should add it incrementally until I have it full when I have time to do so?

Hogwildz, I'll bring that issue of angle up with the shop. When that fire is sucked up, the air is fully open. I havent tried just shutting that when its happening as I want to get it settled asap. I was just up on the roof shoveling and checked the cap when up there and it appears all clear. That was my first thought was plugged but I think Im ok.

BeGreen, You may be right on adding wood too soon. There are times when Im headed for bed or out for the day when it is coals but still up in temp when I load up as its in between and I want it full. Maybe thats part of it. I sure know about the "finesse" you speak. Im still learning thats for sure! Wish Id have found this site BEFORE buying the stove.....As far as the wood, nothing I have is overly dry, just right or borderline Id say. It is a mixture of species all the time, maple, birch, ash, beech....Temps have hovered around 30 give or take for awhile now. We had a warm spell when my draft went to hell but seems ok of late. Its 8 today and supposed to be well below zero tonite and single digits tomorrow....guess we'll see on that draft!!

Thanks to ALL of you who have replied.

 

[dtabor]

Craig,

If you follow the manual, it says 450* but that never seems to take off. Ive had others on here say get it up to 600*+ and have the wood well charred so thats what Ive been doing. Maybe I'll try it sooner the next few days and see what happens.

Thanks for the heads up.

D

 

[webbie]

I think the bed of coals at the bottom is much more important than the actual surface temp of the stove. Any instructions they give are just an indication.

Remember that in EPA testing, they are not allowed too much leeway at time of loading, so the stove must perform with a short load period and then immediately placed into downdraft.

 

[swestall]

Very true Craig; also it really seems to help to have an air path front to back. (I usually try to have it on the right side so air can pull under the ends of the splits and to the coals in front of the opening. I've had times when I thought it was perfect and it'd not light off, then I rearranged the splits so it could get a front to back pull and off it went. I'm thinking of making a little channel out of box stock and putting it in there front to back to see if it has an effect on consistency of the secondary burn.
Coals and draft do seem to be the deal, plus the ability of the burn chamber to pull in the gasses, it doesn't do much good trying to pull in gasses if the wood is blocking the opening....
I think this is where the design is failing; who in their right mind wants to fiddle with the stove until things are just right. Most of us want a load, watch, engage and go stove. I'd bet $$$$ the folks at VC are aware that it is an issue and I hope they are working on it. Looks like the Equinox or Mansfield for us next year.....
Steve.