Defiant wood stove grill problem

[davidj]

This past winter, my defiant stove "puffed" one night (flame failed to start after filling the stove with wood and it smoldered until catching). This sometimes happens if I do not wait for flame to occur prior to shutting down the damper for slow burn. The stove will puff out smoke due to the start of combustion. Not a major problem. But this one time, the puff was enough to actually lift the grill up high enough so it did not come straight down and left ca. a one inch or so opening across the entire back section of the grill. No problems with the rest of the burn, but I was just a bit concerned when I found it that way the next morning.To prevent, I layered several splitting wedges on the grill where they remained for the burn season.
In order to prevent this from happening again, I am planning on screwing a long piece of metal to the bottom of the grill, long enough to reach over the edges of the opening. This would then secure the grill to the top of the stove.
My question is; has anyone else experienced this? And if so, what did you do. And, does anyone know why I should not do this. Thanks.

 

[fraxinus]

If your Defiant is one of the older, original models and the grill you refer to is the oval griddle in the middle of the top, your experience is a fairly common and often unforgettable one - I once saw the griddle plate go up a good two feet and drop straight down into the fire. The design of the stove relies on the weight of the griddle to keep it in firm contact with the gasket around the oval opening. When you get a sudden shot of oxygen, the gasses produced by a smoldering fire ignite and release an impressive amount of energy. Fixing the griddle to the top of the stove as you propose would force this energy to escape somewhere else, potentially causing more serious damage elsewhere. Far better to avoid smoldering fires than to alter the original design, in my opinion.

 

[Jags]

Locking that lid down is effectively creating a potential bomb. So is smoldering that stove. Its called flashback. It has similar qualities to pouring gas on a smoldering camp fire. Ignition is impressive.

Don't do it, and keep that stove rolling. No smoldering.

(Frax - where the heck have you been?)

 

[HotCoals]

Locking that lid down is effectively creating a potential bomb.

What?

I must not be understanding the situation.

Sounds like the stove can be loaded at the top by taking out a griddle/lid or whatever you want to call it.

My stove is only loaded through a secure door in the front. So are you saying my stove is going to blow up on me because I don't have a lid that will release the pressure from a spontaneous combustion episode.

Noway would I want the top cover to be able to be blown off.
I must be understanding this all wrong?

 

[Jags]

I must be understanding this all wrong?

No - I think you probably have it correct. Smoldering a stove to the point of oxygen starvation creates a very serious issue. When the stove gets to a certain point it can and will pull oxygen down the stack if it can't get it from somewhere else. When it does - BOOM. I have had it happen to me ONCE. It was my own stupidity...I used the ashpan door to get a rolling fire going. Not realizing that all the other controls were shut down to bare min. when I closed the ashpan door it only took a minute or two and BOOM. I thought I was going to have to retrieve the stove from my basement.

On that very day I made a couple of observations that have never been lost.
1. NEVER EVER use an ash pan door for startup of a stove.
2. Always have 3 screws in EVERY pipe joint.
3. Realize when there is a potential gas buildup in the stove and fix the issue.
4. Always have a clean pair of skivvies near by.

The OP is creating the same type of environment with one exception - he has a circuit breaker - the lid. It can minimize the force of the BOOM by giving away first. BUT it is far better to not create this situation in the first place. DON'T Smolder the stove. This isn't the first Defiant that I have heard of do this (as Frax above can confirm).

 

[HotCoals]

I understand what you're saying Jags but that's a crummy pressure relief valve (lid).
He(Frax) says it could rise up and fall into the fire on the way back down..good Lord. If I had that stove and it did that it would be scrap,I would not even sell it to anybody else.
If I had to keep it I also would find a way to secure it.
I don't think you could ever blow a stove apart,seems the flue is a better relief system then a lid.
I concur on the screws!

 

[begreen]

I had the same experience as Jags with the Castine when I was first learning to run it. My error, I did the exact same thing. A big flashback/puffback is not one you forget. I was very grateful that the flue system was proper and had 3 screws at every joint.

 

[Jags]

If I had that stove and it did that it would be scrap,I would not even sell it to anybody else.

Wise words. I will leave it at that.

 

[peakbagger]

Many stoves do it, the Defiant just happens to do it with style . If this happens to you more than a couple of times you are not running the stove correctly. Don't blame the stove, blame the operator. More than a few folks sit a trivet and a cast iron tea kettle on top of the griddle. Defiants in general are very high BTU devices and many are installed in spaces that are far too small. Thus the temptation is to get them running, bank them up with wood and then crank down the damper for it to run all night long. This is perfect setup up for booming to occur. Its also a major hint that you are setting yourself up for creosote accumulation. If the stove is too large for the house, then you are stuck with feeding a small fire with small loads on a frequent basis. Defiants were and are real popular with folks in VT with large drafty homes but stick them in small well insulated house and they are just to darn large. Before my wood boiler I had mine installed in a basement. I could run it hard for several hours and it would carry the house over night. It was rare that I didn't have to relight it in the morning as it would burn everything down to ash. Once I figured out that banking it up and cranking down the air wasn't an option I didn't have any issues.

One of the many EPA mods installed on newer wood stoves are hidden air ports so that if a homeowner shuts down the visible air ports there is still enough air for combustion. This could easily be done on a defiant by modifying the air inlet but then the stove will burn loads quickly.

 

[davidj]

Second response; Sorry, did not see all these responses before my first response. Thanks to all. And yes, this was my fault; not the first time I have had the stove puff and it seems to occur more on windy nights, never in the day time, only when stove is on low combustion mode, damper closed down. And usually only in the warmer nights, never when lower than 20 degrees F. There is a port on the stove which I normally leave open for more complete combustion of hot gases (according to stove directions) but I find I get less puffing during the warmer windy nights when I close it off. Probably little more positive pressure in the flue from combustion products
My Defiant is in a big room and open to the rest of the lower floor so not too big for the area. Had a vc Vigilant in an upstairs bedroom when the kids were here, and yes, much too big. Has been replaced with an vc Intrepid . And yes, closed burns do create creosote but I am discharging into a insulated 8 inch flue, so the creosote only forms at the cold top of the pipe and Is cleaned every three months of burn. (8-10 face cord wood/year; wood stacked and covered outside for at least two summers prior to burn, and loaded into garage in July prior to season of burn). Can usually always find enough hot coals to start up in the morning. Leaving the door open a crack really gets the stove active in a hurry.
When this "event" occurred this past winter, the one surprising thing was that none of the smoke detectors went off suggesting that even though the stove was "open", and the damper down, there was still enough draw to keep the combustion products inside the stove/flue.
I will fasten the griddle on and make sure that the fire has started prior to damping down the stove for a night burn from now on. Thanks to all for responding. Nice to know there are other woodburners out there to assist.

 

[fbelec]

i had this happen to me a couple of years ago. it definitely is operator error. you need to go over your manual about secondary combustion. that port you closed should be wide open when you close your damper. that provides the oxygen for secondary fire. if you run with the closed damper and a closed secondary air port (the small one inch round port to the left bottom of the side door) you'll create lots of creosote and the blow back will keep happening via small air leaks from the primary air to the secondary air inlets via cracked cement between the ports. when the blow back occurred on my stove the damper was closed so after it lit off the griddle lifted up the steam dragon and a small coffee maker both full of water and came down crooked because of the weight difference. the plate, coffee maker and griddle ended up inside the stove in the fire. my incident happened because of operator error. it was the last fire of the season for me and i throw in a piece of punky wood that i thought was dry because it weighed the weight of a empty can. the secondary lost fire the when it lit boom woke me out of a sleeping pill sleep and the flame took the shortest route out of the stove. thru the griddle plate hole. jags # 4 is a must. definetly get it going hot before damper closing to start that secondary fire. if you see the flames coming out the top like i did you'll only do it once. run the stove above 600 degree griddle plate so there is no problems bty i did bolt my plate down. in my opinion a must. the later defiants with out the lift top plate for loading were bolted down only the originals were not

frank

 

[davidj]

Thanks Frank, for your response. Secondary air port is open all the time except during some warmer windy nights. If I can hear the damper swinging, I know there are pressures in the stove from the uneven wind pressures at the top of the stack, and I will close that air port; reduces the puffing. (Believe that is according to the manual, but will have to recheck).
Wow! Your incident much more severe than mine. Question I have for you re. bolting the griddle down. How did you do that?. I am planning on running a piece of angle iron two inches longer (on each end) across the bottom of the griddle, and drilling and threading the griddle to attach it to the angle iron underneath. I don't have a lot of thickness to that griddle, and if not thick enough, will have a additional plate welded to the bottom of the griddle to enable me to get more thread depth on the screws. Wondering if you came up with a better way.?? Thanks again for the input. david

 

[fbelec]

your idea is a good one go with it. i used two separate pieces of metal about 1/4 inch thick drilled holes in them and thru the griddle used 1/4 20 bolts into the 1/4 20 threaded holes i put in the pieces of metal. worked perfect. i know what you mean about back puffing when it's windy. if you have to close the secondary air port then open the damper or it will be to cool and smokey and you'll coat your chimney. just run it updraft at about 600 degrees or maybe a tad hotter and it shouldn't back puff. usually when i get that i run it at 650 and there's know problems

 

[fbelec]

the hotter you get your chimney the stronger the wind will have to be to push the smoke back down. if it's warm out the draft will not be good so run a hot shorter fire. if you still have problems your chimney is not very good or to short.