Need advice - why is my fire acting very weird

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joefrompa

Minister of Fire
Sep 7, 2010
810
SE PA
Hi all,

For the past 3 days, both my wife and I have been struggling to get even marginal fires going. We're using the same wood, good kindling, and plenty of newspaper. Hell, I even tossed in 1/2 a super cedar today AFTER 20 minutes of the fire struggling and it didn't do anything. However, I was able to get it going good....

The thing that is getting me is the behaviour. It doesn't make any sense to me, and I only have one theory. Here's what's going on:

1. Plenty of draft - the fires may even start out very healthy and "roaring" but then dies down. If I shut the door within 15-20 minutes of starting the fire, it immediately dies off and doesn't ever really recover. Leaving the door open it just dies slower...

2. Same wood - Semi-seasoned, absolutely, but I've been using it for like 40 new fires without a problem. Further, it's ash that's been seasoned for a few months + pine - two of the best woods for burning semi-seasoned. I've got PINE that won't fire up.

3. Stacking is done in the same way as always. I bundle up like 6-8 pieces of newspaper (ALOT) and put light kindling on top of it progressing to heavier on top. I haven't found the top-down method works well for me yet on thiss tove, but the normal bottom-up has. I then put newspaper in the middle of the pile and on top. I light it up and it goes all inferno...then dies off....

So here's the weird part: It dies off to the point where the small pieces are mostly gone or smoldering, and the large pieces are solidly lit in very specific areas but kinda just sit there with a steady flame licking upwards. The fire doesn't grow and doesn't change (and this is on pine and ash, mind you). The stove stays at or under 300 degrees.

Now here's the weirdest part: Multiple times now I've been able to get it roaring within 15 minutes from that stage by merely re-arranging the lit medium splits and ADDING to the firebox until it's stacked to the top with new medium splits.

This morning I had a smoldering fire going for 30-45 minutes - stove top at 250-275 and door open. I got sick of it and re-arranged the wood and shoved tons more on top. Within 2-3 minutes, the firebox was roaring. I shut the door and took a shower. Came back down in 10 minutes and the stove top was 500 degrees with good secondaries going.

what is going on there?

Here are my only working theories so far:

1. I'm "learning the stove" - I don't really believe this because I've begin extremely successful and its suddenly happened for 3 straight days to both my wife and I, using identical wood.
2. "Heat sink"? - The past 3 days the outdoor temps have dropped to the coldest yet - around 20-25 degrees. My stove is in an exterior chimney and because we haven't had strong fires, I'm sure all that masonry has gotten really cold. Is it possible that the fires are dying off after a strong start because the stove is just not heating up? This seems a little ridiculous, but I do know that my fires will die off if my fan is too high too soon and it sucks all the heat off the surface, so I imagine a really cold chimney could kill the fire off too?

Looking for that helpful hearth.com wisdom :)

Joe

P.s. I have no block-off plate nor insulation behind the stove...I'm going to be buying firebatts (safe to 2700 degrees) and shoving them up around the 6" flue pipe and around the back of the stove, then covering the surfaces of the insulation with heavy duty aluminum foil.
 
either you have gotten into wet wood or else perhaps your chimney cap is plugged.

pen
 
pen said:
either you have gotten into wet wood or else perhaps your chimney cap is plugged.

pen

Draft is great - wood could be wet, but it DOES suddenly fire up after I re-arrange it.
 
Couple ?'s as I read it sounds like an air starvation situation.

1. This is a new insert , are you sure you have the draft control open? ie To me it reads like you are starting the fire with the door open, leaving it open for a bit, then when the fire is established closing the door, and the fire goes out.

2. If the fire rages with the door open, then, you can pretty much rule out obstruction of the chimney and chimney cap.

3. If the fire rages with the door open, then dies when the door is closed, sounds like either poor draft, or obstructed air inlet (double check position of draft control). Is there an OAK? If yes, could the supply tube be kinked off during the install or moving of the unit. If not OAK, could something be blocking the air inlet?
 
Wow! Difficult to say… this type of situation usually is caused by either the wood or the draft.

For what you’re explaining, I definitely think that there’s a strong connection between the colder temperatures, the outside chimney and the “weird” fire. You say your draft is great… are you having any smoke trying to get out of the door?
 
If that is a tile line chimney then the first batch of wood is just almost getting those flue tiles warmed up about the time it finishes outgassing and then there is insufficient draft to burn it through the next stage of the burn. Then when you toss on the new wood it finishes the job of heating up the chimney and kick starting a good draft and you are off and running.

Try this. Split up a bunch of small stuff and start a fire with that. When it has created a nice coal bed then put splits on top of it. It should take off running from there since the flue should be pretty warm by then.
 
Check all of your airflow control, there is something going on somewhere. have you tried using different wood, just to rule that factor out? get one of those $5 bundles from the gas station/supermarket and see if the issue persists. If the fire is fine when the door is open but then starts to die out when you close it, then something somewhere is starting your fire.
 
After an established fire has gone to coal stage and you are adding new fuel, how does it act? Slow to fire back up - raging after a few minutes. Do you need to crack a door on the new fuel load, or will the normal draft control work just fine?

I'm suspecting the "perfect storm". Cold tile (draft) and questionable wood. The colder the outside temps, the longer it takes to heat the flue, lack of draft, the uglier it is to get a good fire going.

I like BroB's idea of starting a "flash" fire to get those tiles warmed up.
 
joefrompa said:
I light it up and it goes all inferno...then dies off....

So here's the weird part: It dies off to the point where the small pieces are mostly gone or smoldering, and the large pieces are solidly lit in very specific areas but kinda just sit there with a steady flame licking upwards. The fire doesn't grow and doesn't change (and this is on pine and ash, mind you).

I'm going to counter the popular wisdom and say the cold weather is giving you a bit too much draft for your marginal wood. It seems you are getting plenty of initial draft, but then your dry paper and kindling is burning up too fast to fully ignite your larger, unseasoned splits. Try splitting your splits smaller and pre-drying a stash just for fire building.

My experience is that pine and ash season more quickly, but that does not equate to them burning well when unseasoned. Green pine is all water weight, very hard to burn. They will burn ok on a well-established fire, but maybe not one you are starting from scratch under certain conditions.

Seems it's a combo of the wood and the weather - the cold either increasing the pressure difference and giving you a draft that's "too good" for your wood, or the cold cooling your flue and stalling the draft. Based on your description, it seems like the former to me, not the latter. Don't have a key damper in your pipe, do you?
 
Jags said:
After an established fire has gone to coal stage and you are adding new fuel, how does it act? Slow to fire back up - raging after a few minutes. Do you need to crack a door on the new fuel load, or will the normal draft control work just fine?

I'm suspecting the "perfect storm". Cold tile (draft) and questionable wood. The colder the outside temps, the longer it takes to heat the flue, lack of draft, the uglier it is to get a good fire going.

I like BroB's idea of starting a "flash" fire to get those tiles warmed up.

+1 - exterior clay tile chimney needs to get warmed up on these colds days. Initial fires should be small splits for hot fires. Are you burning 24/7? If not, you'll be dealing with this situation quite often I think. Perhaps you were doing well earlier due to warmer outside temps and therefore a warmer flue that could get up to temp quicker to produce a better draft sooner. Cheers!
 
This morning I had a smoldering fire going for 30-45 minutes - stove top at 250-275 and door open. I got sick of it and re-arranged the wood and shoved tons more on top. Within 2-3 minutes, the firebox was roaring. I shut the door and took a shower. Came back down in 10 minutes and the stove top was 500 degrees with good secondaries going.

what is going on there?

Maybe you are not "huddling" your wood enough? In other words, if you are criss crossing or otherwise leaving big gaps in between your wood then it won't burn well.

If that's not the case, then you'll find that wet wood will take off a heck of a lot better when it's loaded on top of hot coals. Really, any wood will take off a lot better when loaded on top of hot coals.

pen
 
Hi all,

Good things to consider here. A few thoughts to add:

1. I have a 13' "Forever flex" insulated stainless steel liner going almost straight up (has about a 20 degree bend shortly after coming out of the stove, and then straight shot up). The chimney itself is a brick unit - I don't know if the inside is tile or what.

2. It's definitely possible I need to "huddle" the wood more. Unfortunately, alot of my pieces right now are long. Now, that was working fine for like 40 days - again, the wood I'm using is identical, I have almost no variation in my stock of wood. However, I re-arrange it and it takes off...so perhaps there is a "huddling" component going on here.

More info to come!!!
 
Another thing to consider although it does sound like your cold chimney and marginal wood are the main culprits, all that newspaper you are using may have clogged something up. I saw how much newspaper was in my clean out after my first year of burning and have not used it since.
 
Maybe a negative pressure issue?? Try cracking a window open as close to the stove as possible. See if that changes the way it reacts.

Kinda sounds like it with the first part of the fire taking off, then dieing off.
 
Let's factor in this post from Joe on December 3rd.

"This thread has me concerned: I’ve got a ~13’ insulated SS liner, almost a straight shot up. With my draft wide open and my damper bypass pulled out (opening a straight shot up the liner), when I open the door I’m ok. But when I slowly pull the door open I still get puffs of smoke coming into the room - sometimes large puffs.

This happens pretty much everyday.

Does this mean I have a problem with the draft? It’s worst when wood is smoldering or on fire close to the door, which seems natural, but it happens pretty much all the time unless the fire is roaring (i.e. only time it doesn’t happen is when fire is 500+ degrees). "
 
Just FYI you can get OK draft with the door open, even if the cap is partially plugged. I have seen it.

Had one where the fire was smouldering inside with the wife in there. The husband and I went up on his snow covered roof IN THE DARK (yay...) and cleaned out his cap. Came back down and his wife was like "what did you do up there??? the fire started going really good all of a sudden".

So have you checked the cap yet?
 
jtp10181 said:
Had one where the fire was smouldering inside with the wife in there.

Against the law in some places. Not to mention the creosote.
 
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joefrompa said:
Hi all,

For the past 3 days, both my wife and I have been struggling to get even marginal fires going. We're using the same wood, good kindling, and plenty of newspaper. Hell, I even tossed in 1/2 a super cedar today AFTER 20 minutes of the fire struggling and it didn't do anything. However, I was able to get it going good....

The thing that is getting me is the behaviour. It doesn't make any sense to me, and I only have one theory. Here's what's going on:

1. Plenty of draft - the fires may even start out very healthy and "roaring" but then dies down. If I shut the door within 15-20 minutes of starting the fire, it immediately dies off and doesn't ever really recover. Leaving the door open it just dies slower...

2. Same wood - Semi-seasoned, absolutely, but I've been using it for like 40 new fires without a problem. Further, it's ash that's been seasoned for a few months + pine - two of the best woods for burning semi-seasoned. I've got PINE that won't fire up.

3. Stacking is done in the same way as always. I bundle up like 6-8 pieces of newspaper (ALOT) and put light kindling on top of it progressing to heavier on top. I haven't found the top-down method works well for me yet on thiss tove, but the normal bottom-up has. I then put newspaper in the middle of the pile and on top. I light it up and it goes all inferno...then dies off....

So here's the weird part: It dies off to the point where the small pieces are mostly gone or smoldering, and the large pieces are solidly lit in very specific areas but kinda just sit there with a steady flame licking upwards. The fire doesn't grow and doesn't change (and this is on pine and ash, mind you). The stove stays at or under 300 degrees.

Now here's the weirdest part: Multiple times now I've been able to get it roaring within 15 minutes from that stage by merely re-arranging the lit medium splits and ADDING to the firebox until it's stacked to the top with new medium splits.

This morning I had a smoldering fire going for 30-45 minutes - stove top at 250-275 and door open. I got sick of it and re-arranged the wood and shoved tons more on top. Within 2-3 minutes, the firebox was roaring. I shut the door and took a shower. Came back down in 10 minutes and the stove top was 500 degrees with good secondaries going.

what is going on there?

Here are my only working theories so far:

1. I'm "learning the stove" - I don't really believe this because I've begin extremely successful and its suddenly happened for 3 straight days to both my wife and I, using identical wood.
2. "Heat sink"? - The past 3 days the outdoor temps have dropped to the coldest yet - around 20-25 degrees. My stove is in an exterior chimney and because we haven't had strong fires, I'm sure all that masonry has gotten really cold. Is it possible that the fires are dying off after a strong start because the stove is just not heating up? This seems a little ridiculous, but I do know that my fires will die off if my fan is too high too soon and it sucks all the heat off the surface, so I imagine a really cold chimney could kill the fire off too?

Looking for that helpful hearth.com wisdom :)

Joe

P.s. I have no block-off plate nor insulation behind the stove...I'm going to be buying firebatts (safe to 2700 degrees) and shoving them up around the 6" flue pipe and around the back of the stove, then covering the surfaces of the insulation with heavy duty aluminum foil.

I've had some issues over the past several days with the strong winds we've been having. Cold starts were a pain, keeping temps up were a pain. Adjusting air control was a pain. Mostly on the Intrepid.

Did your issues ease up today? Because the wind died done around here and all of a sudden the Intrepid went back to burning far more easily.
 
BrotherBart said:
Let's factor in this post from Joe on December 3rd.

"This thread has me concerned: I’ve got a ~13’ insulated SS liner, almost a straight shot up. With my draft wide open and my damper bypass pulled out (opening a straight shot up the liner), when I open the door I’m ok. But when I slowly pull the door open I still get puffs of smoke coming into the room - sometimes large puffs.

This happens pretty much everyday.

Does this mean I have a problem with the draft? It’s worst when wood is smoldering or on fire close to the door, which seems natural, but it happens pretty much all the time unless the fire is roaring (i.e. only time it doesn’t happen is when fire is 500+ degrees). "
This would lead me to believe that he is suffering from Back Puffing, or Whuffing. Good article on it hear. http://chimneysweeponline.com/howhuff.htm
 
You've stated clearly that you have marginal wood this year, so I'll echo the question: have you inspected the chimney cap and liner for creosote? The cap can become plugged very quickly, inhibiting draft and leading to very sluggish fires. I would inspect both right away. We had a member here gum up his system in just 2 weeks by not burning hot enough to achieve clean burns, so it can happen faster than you realize.
 
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