Help with near over fire, loading for overnight and more

Hi guys,

First season with an insert - I installed a used VC Montpelier that appeared in very good condition. Now I'm having some problems figuring it out and thought I'd post while monitoring my 685 degree fire that is raging away and going to keep me up for the next few hours. It seems to be cruising at this temp now but I can't go to sleep until it settles down more.

So what happened today was I started a fire from cold. I didn't get a very even start on the wood and the fire never got up to 550 like I wanted. I could only get it to cruise around 450.

Well I reloaded on a full bed of coals, all pine that is about 15% or so, and it took off like a bat out of hell. I had the air fully closed within two minutes or less but the wood just off gasses like crazy and the secondaries were insane. I monitored stove top with an IR gun, most areas read about 650-700 but one hot spot got up to 820.

At this point I ran outside and got a wet piece of wood and threw it in.that helped a bit but 10 mins later it was climbing again...725...740...chit, I better do more. So I fetched the pail of ashes and threw some on. That took it down to about 600 and then it has climbed back to about 685 and has been steady for the last 45 minutes.

So a few questions... What did I do wrong and what if anything might be wrong with the insert?

I've never tried to load for an overnight burn before as the insert is a secondary heat source for us, but I thought I'd try it tonight. I've heard to be careful when loading on hot coals but I turned the air all the way down almost immediately. What else could I have done?

Is it always a bad idea to pack the firebox when you have a lot of hot coals?

Was the issue caused by the wood being pine and being quite dry? I haven't burned any hardwoods yet so am not sure how different they off gas or how much more controllable they would be.

Is the issue possibly something wrong with the insert? I can get it down to a very lazy flame and sometimes even snuff the fire (or at least get it to where all visible flames stop) but only ever after the initial 30-45 minutes of intense off gassing. During that phase it seems like I am at the mercy of the wood. It seems like if I am getting too much air - and I'm not sure that I am - it would be from the secondary tubes and not from the door. The intense action is always at the top of the firebox, when I have small primary flames at the bottom of the firebox they are lazy with the air down, no sign of air leaking in through the door. Not sure if a loose gasket somewhere on the Montpelier's body (it is a full cast iron insert) could be the cause??

So, I guess any thoughts as to what I did wrong or how to tame that extremely volatile initial off gassing would really help. Not sure I can get an overnight load on just pine in this 2.1 SF firebox but I think I should be able to...I've had coals 6 or 7 hours later already and that was only with 4 or 5 small/medium splits in there.

Oh some additional details - it's about 15 degrees here (coldest it has been yet since I started burning, thinking that probably increased draft). I've got 17 feet of stack (one three foot piece of flex liner that connects into duravent double wall insulated oval liner) and it's an exterior chimney. Draft has always been real good (or maybe the insert is leaking air somewhere?)


And an update on the fire...almost all flames are gone now (wow that was fast) and it's down to 585 stove top now. Phew!

Hogwildz said:

First off, your temps are nothing to soil your undies about, they are pretty normal.
Many of us cruise at those temps.
You want to reload on a bed of colas hot enough to relight the new load, but not a firebox 1/2 full of coals.
Loading larger splits will also help keep it from going nuclear, especially if you loading pine. Last thing you want to do is load a bunch of small splits of pine on a thick, hot bed of coals.

For excessive coals, pull them forward in the firebox in a pile, and open the air some to get the heat from them, and burn them down. Coals have plenty of heat in them also.

Those temps are fine, nothing I would lose sleep over, and typical cruising temps round here.

Click to expand...

Thanks for the reassurance hogwildz.
It was the 820 peak that had me scared. It was still climbing at that point. I'm not too scared of 675 but with the ball of fire second daries that just kept raging I was worried it would climb again once the ash covered pieces of wood started to ignite again.

Is it normal to not be able to control the secondaries when loading too much dry wood on a big bed of coals?

I was also watching the temp of the piece of flex liner that I can hit with the IR gun (about 6 or 7 inches above stove top) and that was reading at about 460 for most of this time, although it peaked at about 540. Any idea what that roughly translates to for actual flue gas temps and was this dangerously high?

I just saw this video posted in another thread and it showcases what I ran into....however I had my air control all the way closed and the secondaries still looked pretty close to the beginning of this video...is that indicitave of an air leak or is an uncontrollable secondary to be expected with lots of very dry pine on a hot coal bed?

thanks guys. good to know it probably isnt the stoves fault as much as operator error. I'll be careful with this pine and keep my loads smaller and wait til the coals have burned down and the stove is cooler

and yeah i had the blower on high and it wasnt helping much but the design of my insert (vc Montpelier) only has the air flow over the sides of the top and not the center. a decent design to keep it hot under normal conditions, but not so great during a runaway fire

the manual mentions burning softwood...just says to make sure it is dry. no problem there lol.

it says an uncontrollable fire is a sign of too much draft but ive only got 17 feet of pipe (although it is insulated rigid liner so the smooth walls should draft better than corrugated)