"coking" the wood?

[zmender]

I'm wondering if y'all experienced something similar...

Starting with a really thick layer of coal bed and time for reload. However to not let the stove runaway, I turn the primary down to 25%, 50%, which is enough for the logs to start gassing and get a really rigorous secondary burn going. However if look closely at the log near front... it's not hot. The small splits are not catching and 15, 30min later, still with really rigorous secondary burning, I notice the log face near front is barely charred.

Come back an hour, even hour and half later... secondaries are now pretty much dead, my coal bed is pretty much dead, and all the logs I tossed in are just gigantic chunks of black charcoal that's smoldering away without any flame, and I don't have enough coals to relight.

Did I end up with a couple of wetter-than-rest logs? Or I turned down primary too early?

 

[begreen]

Could be poorly seasoned wood, or perhaps the air was turned down a tad too much. Is this with E/W loading or N/S?

 

[zmender]

E/W, and annodoctaly happens more often with the larger, "squarish" splits 4, 5in

 

[begreen]

E/W fires can be slower to burn because the front log acts as a barrier to the air from the airwash. If the wood is not well seasoned, the drier outer part of the wood may burn briskly, but the damper inner core may need more air to sustain combustion.

 

[Jags]

Yep, either wet wood or lack of combustion air.
With a fresh reload I typically open the air fully till my stovetop gets close to my operating temp. Then I pinch it down.

 

[Poindexter]

I can get mounds of charcoal left behind in my catalytic stove two ways, one turning the throttle down "too soon" and two turning the throttle down "too low."

The other controlling variable is how cold is the outdoor ambient air. In colder weather total draft of the chimney system will be 'more,' so the settings to get charcoal left behind are different.

I don't sweat it. The primary purpose of my stove is to keep the house warm. With that goal met, I occasionally in the shoulder seasons have to burn down some charcoal to clear out the firebox.

If you are in a prolonged weather pattern that has you making a lot of charcoal you could pull some of it out of the stove into a metal bucket, then dump it into a snowbank outdoors somewhere. Come spring melt, when the charcoal is demonstrably not on fire, grind it up and add it too your compost heap if you are running behind on brown, or add it directly to your garden beds. Charcoal made from wood is an excellent soil amendment.

 

[stoveliker]

Or you put it in your ash bucket, and put it back in the stove at a cold start. Charcoal works nicely to establish a hot fire core.

 

[zmender]

Using an insert and no good way of gauging STT / FT, I worry overfiring the stove.

For fellow insert users… how do you measure temp of the stove?

 

[begreen]

Using an insert and no good way of gauging STT / FT, I worry overfiring the stove.

For fellow insert users… how do you measure temp of the stove?

What insert brand/model?

 

[zmender]

VC Montpelier

 

[j7art2]

I've been experiencing similar in my Osburn, especially on warmer shoulder season days. My solution before this stove, and now currently with it has been to use more softwoods during the shoulder season months and saving more of my hardwood for winter. I generally do 2-3 hardwood splits or rounds in the center of my stove with a piece of pine slab on each side. Once I run out of pine, I'll switch over to poplar. It's been working well for me.

 

[BotWoogy]

Using an insert and no good way of gauging STT / FT, I worry overfiring the stove.

For fellow insert users… how do you measure temp of the stove?

I shoot a laser in between the fireplace and the chimney, it’s a 2-3 inch gap at the top. I read the temp of the exhaust gases there. It’s through what I believe would be double wall pipe. I also shoot the laser at the top of the fire place. For the temp on the stove I try and stay under 500. For the temp on the chimney I try and stay at 500. 400 is ok. But 600 and up I turn the fans on to cool it down. So, use a laser and find a spot to point it.

 

[Corey]

... Did I end up with a couple of wetter-than-rest logs? Or I turned down primary too early?

I would say either one, but it sounds like the latter for sure. When you throw a fresh load of wood in, that is a lot of mass to warm up. Fortunately it also has a lot of very volatile gasses to 'boil' off. So you can still get pretty good secondary flames for a while. When gasses coming off have flash points of 100, 200°F, they can light off no problem. Eventually those are gone and you start getting into heavier gasses with higher flash points. If you haven't gotten 'ahead of the curve' at this point. (Meaning you don't have an active wood fire / coal bed feeding heat to the secondaries) then the whole cycle is going to die out.

On several occasions (when I goof up) I've looked into my stove and it seems like 'nothing' is happening. I open the ash door just a bit to get some air into the coal bed, a small flame pops up around the wood and 'WHOOSH!!' the secondaries light off in a spectacular light show. Well, all that smoke gas was already there... going up the flue...it just needed that extra bit of heat/flame to actually light off. This can actually happen in a more violent way called a 'backpuff' where a fresh load of wood fills the whole stove with very light/flammable gasses and they all light at once with anything from a pronounced 'WHOOF!' to somewhat of a muffled 'BOOM!' and usually spew smoke and ash back into the room.

So bottom line, when you reload, work to keep a decent fire going on the wood itself and close down air in stages so the wood keeps burning. That way you are still feeding heat to the secondaries and always have a 'pilot light' of fire to light any secondary fire / flammable gasses.

 

[EJL923]

i have e/w setup, and my question would be do you have doghouse air jets on the front bottom? I have two, one plugged, and 99% of the time that jet will laser a hole right through no matter what there is in front. I use it to my advantage frequently. If im saving a fire i will pile up what little coals there are right in front of that air hole and let it do its thing on a split.

Basically, most often i dont worry about having to get the logs up to temp, i keep the primary air closed and let the jet work. IF you have one, could be beneficial. Pipe has been fine for 10 years doing it this way. I have very good draft as well. Just a thought.

 

[zmender]

Thanks Corey for the insightful response. BotWoogy I haven't thought of the laser before... I'll keep an eye out for one on sale.

​

@EJL923 - doghouse air jets? What are those? I have the 3 primary air intake holes at front bottom. Are you referring to these?

 

[EJL923]

Thanks Corey for the insightful response. BotWoogy I haven't thought of the laser before... I'll keep an eye out for one on sale.

​

@EJL923 - doghouse air jets? What are those? I have the 3 primary air intake holes at front bottom. Are you referring to these?

dont know what stove you have or what the intakes are, but on mine there are 3 in total. Primary, comes in from the top of the stove and washes over the glass towards the bottom of the fire, secondary inlet in the back provides air for the secondary tubes, and air coming in front, bottom, center. I believe people call these doghouse or zipper air. I think its to stop fires from smoldering. On mine, its not adjustable, two 1/8 diameter holes that with great draft shoot directly at the coal bed. I stuck a screw in one because they really eat away at the fire with good draft.

 

[Fod01]

In my experience, the Montpelier doesn't have the efficient secondaries of other stoves. Many times I turn the air control to half, but I'll see smoke coming out the flue even with decently active flames in the firebox. I usually swear a bit and open the air back up until the wood is better involved.

For a temp reading, I hit the top of the door with a laser thermometer, about 4" left of center. What is considered a 'good temp' is by experience. On a cold day, and the stove is doing its job well, hit the door with the thermometer and remember the reading.

Conversely, when the stove is low on coals, a temp in the low-mid 200's tells me that I'm going to have a rough time just chucking logs in for a reload. I'll usually pile the coals up on the left side with a bit of kindling to ensure it lights off quickly.

You didnt mention if you rake those coals forward or not. When there are lots of coals, rake them forward, but not so tight as to block the air intakes. Treat the coals like the first log. Load in back of them, and put a small log on top.

Black coals are cool, and indicative of less that optimum wood. I've got that. If thats the issue, dont load as tight, and give it more primary air.

Hope some of this is useful.

 

[zmender]

Just bought a $18 laser thermometer.

Yeah I rake my coals to the very front right over the primary air. This gives me more space in the back to load larger wood and on a good day I can rekindle a small pink/blue flame from the coals on a hot enough bed, or able to bring dead coals back to a pile of red glowing coals.

This stove is definitely a PITA to operate.... and loses so much efficiency and burn time once I turn the throttle up. In couple years when it's finally time to replace the stove, I want something that can burn 20k-30k BTU range steady, steady, steady.

 

[Fod01]

.

This stove is definitely a PITA to operate.... and loses so much efficiency and burn time once I turn the throttle up. In couple years when it's finally time to replace the stove, I want something that can burn 20k-30k BTU range steady, steady, steady.

Easy enough to operate, for me anyway. Feed it dry wood and I'm very happy. Not so dry and I have to take more time adjusting air, and cleaning glass.

Right now that fan is rattling a bit, and getting on my nerves. I haven't found an easy way to replace the bearings, so I just stick in some lube where I can.

 

[zmender]

@Fod01 How often / any tips you have for keeping the glass clean on this stove? Even when I'm burning driest wood (2~3 years locust), the top 1/3 of the glass gets clouded, as it seems where the secondary tube burner directs the air.

Where do you typically operate this stove in terms of throttle? I feel anything >50% I don't really get much more heat since most of it is going up the flute.

 

[Fod01]

@Fod01 How often / any tips you have for keeping the glass clean on this stove? Even when I'm burning driest wood (2~3 years locust), the top 1/3 of the glass gets clouded, as it seems where the secondary tube burner directs the air.

Where do you typically operate this stove in terms of throttle? I feel anything >50% I don't really get much more heat since most of it is going up the flute.

When you say >50% you mean left of center? Then yes I agree, the heat is going up the flue. Most everyone runs their stoves 'shut down' as much as possible. Keeps the heat in the box.

When the stove is cruising, my air control is about an inch from the right. I've rarely done full right without getting some clouding.
This can change of course. If its not that cold out, if the wood isn't great and I've packed it too tightly, then I may have to let it sit in the middle.

Interesting that the top of your glass gets clouded, usually its the hinge side for me. Check for smoke coming out the chimney. My guess is that you just need to let the wood get charred a bit more before before shutting the air.

 

[begreen]

Air controls are rarely linear. Wide open to 50% on many is just for starting a fire. On our stove, once the fire is burning well, the control is in the last 1/2" of travel.

 

[zmender]

Laser thermometer just arrived, yay new toy!

"STT" the portion where stove top branches to flue is at 300~350 right around a hot reload. 15min after, the same area is around 450~480. This is typically when I turn down the air readying for bedtime.