Just Over Fed My Cat

I suppose one is expected to do all the dumb stuff in the first year of burning a new stove, so mark one more off my list. Wood box was almost empty and had a bunch of small diameter rounds/splits in it; decided to load them in the stove since EPA stoves like small stuff (well, I remember reading that somewhere). Everything is going fine until the off gassing peaked. This is when I noticed what sounded like a plane flying outside over the house ... nope ... the noise was coming from the stove. Sounded a bit like a big torch was inside the top of the stove and part of the stove pipe.

Stove pipe was in the normal temp range and the STT never exceeded 550, but for several minutes I did not enjoy the theatrics of catalytic wood burning 101. Went outside and for the first time saw a very small amount of smoke coming from the chimney. After another minute or two the show was over and the blow torch sound stopped; stealth burning mode resumed and my blood pressure slowly returned to normal as I contemplated the event.

My take away from this:

• split big - everything will season with a 5 year plan
• no more than a few pieces of the small stuff in any load
• the hybrid design would likely avoid this scenario - perhaps I should be more open about them

 

You know Jon Arbuckle?
Or Odie...maybe Nermal?

 

Now I do thanks to google. Odie rang a bell, but not the other characters. Did Garfield pop into your head when you saw the title of the thread ... or did I do something worthy of a cartoon character ?

 

Gotta watch over feeding!

 

This isn't the first time I have experienced the blow torch effect ... only the first time with the new stove. My old Hearthstone would occasionally do this and like your stove it was not at all air tight.
Always a rather tense time for me even though there probably isn't much to it other than being out of the ordinary. Always seems to be over pretty quickly. Wasn't sure if having a 28 foot SS chimney made this happen more or less infrequently than others with shorter stacks.

 

Well, it really does not sound like anything really happened anyway. And as to dumb stuff, not really seeing that either- you are merely learning about your stove on your chimney with your wood, just like all the rest of us I think. An important thing to remember is that no two wood fires are exactly alike so what you experienced sounds more like a quick, hot fire rather than anything wrong.

The only thing that is a bit off- putting is the loud 'plane' sound; woodstoves are not usually loud, even when over- fired. The age- 0ld thing that does make a lot of noise is a chimney fire, and that is always a concern. You may have had a small amount of creosote burn inside the chimney- I would suggest checking the inside of the chimney (from the clean- out door, with a mirror and a strong light) fairly quickly. You also may have had a bit of a creoste fire in either the smoke pipe and / or the thimble if it was very loud in the house. But aside from that, I think all is well with your experience.

As far as a stove "running away", that was basically much more of a problem with older stoves as they had leaks, gaps and were just not all that well sealed usually. A pot belly, cast iron stove is a perfect example: all closed down they really were not really closed down. Modern stoves, be they secondary burn, pure cat. stoves or hybrids, typically do close much more tightly than the old stuff. So shutting all the air input is usually pretty successful although of course no EPA approved stove that I know of can actually be really 'closed' so they do not smolder. But you can take steps to address even that by finding and manually blocking any / all aux. air inputs in a pinch to cool a 'too hot' stove until it is back under control and at a reasonable temperature.

Brian

 

Yup!

 

Oh yes, a tall, well- insulated chimney exacerbates the problem due to excessive draft. I went from a ~20' masonry chimney to a ~28' stainless steel, insulated chimney and my Ideal Steel has become a bit of a beast to run. The new 'low' is far more aggressive than the old 'low'- I am even thinking about installing one of the dreaded stove pipe dampers although I am not sure that would really address the problem either as they still pass a lot of air when fully 'closed'.

Brian

 

Actually, it wasn't loud at all. I have exceptional hearing and happen to notice sounds out of ordinary - this was simply that - first thing that came to mind was a plane. Just inspected the stove connector pipe and top perhaps a week ago and there was only a bit of fly ash and certainly no creosote. Chimney was swept at stove install and I have run about 1 cord through the stove. I have experienced the blow torch sound with my old stove, so I'm not totally unfamiliar with it.

 

I had Woodstock install one in my 1 foot pipe "just in case"; certainly needed it with the hearthstone, but have not used it with the Fireview. May use it when it gets real cold and windy, but turning down the air has always been sufficient with this stove where it had little impact with my old one.

 

Thanks.

 

So it sounded like a jet engine. Any cat stove is going to have a separate air supply feeding to the combustor along with the smoke so it can do its magic. A secondary combustion stove burns volatiles by introducing fresh air (typically via tubes) to the gasses when they get to 1100° f. So, what's to stop secondary combustion from happening in a cat only stove when volatiles (at 1100° f.) meet the fresh cat air? Secondary combustion - the gasses ignite before they go through the cat and sound like a blow torch. My old Encore 2550 cat stove did that pretty often and the IS sometimes gets 'sled flames' hovering upstream of the cat. It's no problem to the stove, the cat just has a little less work to do.

 

Perhaps a very small jet. I would like to see what is actually happening under the top - just not curious enough to open the lid when it is happening. I plan on it not happening again if at all possible; won't be from loading too many small pieces.

 

Prior to the fireview our down draft stove would honk, growl and sound like a jet, but you would observe it with temperature readings. I've never experienced a jet sound from our fireview or blow torch effect. I have heard the stove pipe and air inlet whistle though.

It's possible like others have said you had a small amount of creosote burn in the connector piper or under the top lid?

I've found the fireview exceptional at burning small and large pieces alike, my favorite part of the stove is having only one air inlet that can darn near be shut tight. A lot of other stoves have unregulated secondary air which is terribly problematic with when you have a very tall stack that pulls like a freight train. (at least in my experiences).

 

I had that same thing happen once with the stove stuffed full of small rounds and splits. No chimney fire, no creosote and made it through it just fine.

 

I will believe this is possible if someone can explain to me how this creosote could form in the hottest part of the chimney from burning just under a cord of wood in the mid to high teens in MC in an EPA 1.3 g emission certified stove. It would be more plausible for creosote to form at the top of a 28 foot chimney as it cools down, but this doesn't even seem plausible considering the stove I am using and the amount of wood burned. I've been burning 24/7 for a month now, so the cat is almost always engaged; on cold starts I use a top down fire - there just appears no way for creosote to form. But, if I am wrong about that, there is a bigger problem - if it can form in these conditions - what is any reasonable burner to do to prevent it?

This seems to be related to my tall chimney as it has now happened once with the Fireview but occurred many times a year with my old down draft Hearthstone. My sweep always reported good results from our cleanings and I have no reason to think he would be telling me anything other than the truth.

Here are some pictures from two weeks ago. The connector pipe and key damper looked good, but I did not snap a picture - only looked at them using a flashlight. I don't consider the carbon on the lid to be creosote.

 

I like an assortment of 4"-6" splits, so I can pack the box full. With only 16' of stack, I can burn pretty small stuff and still have enough air control to select my burn rate. I've never heard that "blowtorch" sound since the old days when I had wet wood and chimney fires. You may have to split a bit bigger than I do with your tall stack.

Yep, with the lighter stuff more wood will get gassing quicker than with dense woods.

I'm thinking a small stack fire could possibly have happened. Did you see any flaky stuff on the ground, that may have blown out the top of the stack during this event? But I don't know; If it wasn't loud, maybe smoke was getting into the stack and igniting there somehow. Seems unlikely, though, as does a chimney fire. Maybe it is something to do with the tall stack. At any rate, I wouldn't worry about it too much, and I bet it doesn't happen again unless you were to load a bunch of small stuff...

The Fireview, Keystone and Buck 91 don't have dedicated cat air, they just feed on air wash air.

Agree, if anything you would have a little creo at the top where the stack exits the house and it is much cooler.

 

Do you have single wall pipe or double wall going to the thimble?