Newbie with runaway fires - Help!

Hi,

This my first season burning wood and I need help. I had a new Lopi Endeavor installed with double wall pipe that goes straight up (no bends/elbows) through a centralized location of a one story ranch. I am using a new Condor Inferno stove top thermometer to monitor temps.

When I burn with seasoned (18% on my moisture meter) pine I have no problems getting the stove to 550F and then partially closing the air intake and letting the secondaries do their magic. The temp might get to 600 - 650F but I can close the air intake further and the temps start to go down.

The problem I am having is when I burn with red oak and beech. When I get the temp to 500F and partially close the air intake the secondaries go WILD. I close the air intake all the way but the temp quickly spikes to over 700F. At 750F I panic and and cover the air intake holes (even though air intake is closed all the way) with my hearth gloves, sit pots of water on the top of the stove, and point a box fan at full speed on the side of the stove to dissipate the heat. This method still takes me over an hour to get the stove back around to a 500F range because the secondaries won't stop aggressively flaming.

As far as the oak and beech go, they are small splits 2-3". I re-split my wood this small because this is my first year burning and I couldn't find any hardwood under 30% on my moisture meter.

Also, when the runaway fires occur, it happens when I tightly fill the entire firebox with the 2-3" splits of the oak and beech.

I have had three runaway fires in two weeks. Thankfully, I got each one under control after much anxiety and sweat!

This makes me want to only burn with pine which doesn't put off extended heat like hardwood.

What am I doing wrong? Please help

Grisu said:

I am surprised that you don't have problems with the pine, too. When I load my stove with dry pine I have to be careful not to overfire it.

Are those reloads on hot coals or fresh burns? If those are reloads try to move all the coals towards the door. With that the splits in the back will catch fire later. Also, the stove and flue are already warm; no point in waiting to 500 F to close the air. I start closing mine as soon as most/all of the wood is engulfed and I have it mostly closed already around 450 F. I look more for the fire than the temps. As long it is not smoldering and the secondaries are going you are fine. You can always give it a bit more air again if you overdid it.

When you have an overfire: Get a magnet to cover the air intake. No need to sit there the entire time. Another (counterintuitive) option is to open the air all the way open again and crack the door a bit. Since you have a bypass you should also open that one. That way your stove operates more like a fireplace and most of the heat goes up the chimney.

Click to expand...

These are on hot coals. I never thought of opening the bypass damper, I suppose I can give that a try. Last night when this problem happened again, I tried reducing air intake around 400F - 450F and it kept choking. So I gave it more air until 500F and that is when the secondaries go crazy and temps begin to spike.

Sprinter said:

Same here. I think you're waiting too long to start shutting down.


This option makes a lot of sense but I've only heard of one person here who actually tried it. Mainly because it would take some courage to do it...

How tall is your chimney? Could it be that your draft is unusually strong?

Click to expand...

The chimney is about 4 feet. Yes, I was wondering if my draft is too strong as well.

rideau said:

Don't resplit the wood. If you re having run away fires with the resplits, you'll likely be fine with the original larger splits. A stove full of two inch splits is asking for short burn times and excessively high temps. A few smaller splits and the rest large should work just fine.

Click to expand...

My large splits of oak are still around 30% moisture content - that is why I have avoided using them. Perhaps I can use a couple of the larger ones with the smaller splits.

Sprinter said:

Those splits seem pretty small. If you stuff the stove with them, they would want to take off too fast. You may not have that problem with much larger splits. There's too much surface area exposed, causing excessive off-gassing.

Are your pine splits larger?

Click to expand...

Yes, the pine splits are much larger, around 5 -6 inches.

Motor7 said:

It is also possible he has an air leak somewhere...I'd take a close look at the stove & check the draft, it could be excessive..

Click to expand...

Maybe I have a leak, but I don't think so. It is a brand new stove plus when I close the air intake on lower temp fires and on larger pine splits I can choke the fire fairly easily. What other leak situations should I look for?

eclecticcottage said:

I believe you should open it ALL the way instead of cracking it. Cracking it will make the air rush in like a mini turbo charger. If you use this method, be careful of embers popping out.


If you're reloading on coals, try to rake them forward into one spot. Try not to have them spread out.

Don't focus too much on the top temp when shutting it down, watch the fire and it will tell you what you need to know. Once it's established, start shutting it down. If you shut it down a little two fast and it chokes out, open up a bit and it will come right back.

I have the sister stove to your Endeavor, the Republic. They do like to run hot and will take off easily (our flue set up sounds like yours-double wall to the ceiling through a small attic and out). Ours will run up to 750 on a hot reload every time if we don't shut it down quick enough. Even if we do, it will run up to 650-700 pretty quick.

We didn't shut it down quite quick enough last night and it topped at 750, if it had kept climbing we would have been opening the door to break the secondaries. Makes me laugh kinda when people post how they don't want a cat stove because of how scared they are of using the controls, but my take from reading here is they are WAY easier to rein in than tube stoves. Love my stove, but it's a tempermental beastie, it really takes proper care and feeding etiquitte!

Click to expand...

Lopi says not to run my Endeavor over 800F so I panic when it gets in the 700 - 750F range. Perhaps for this stove, it is normal to run this at the 700F range. I just get concerned that it will continue to go up to 800F and beyond and get out of control. At least my stove has not gotten hot enough to where it has started to glow!

lopiliberty said:

700 to 750 is now big deal for the endeavor and can probably cruise there for hours at time I know my liberty does. I'm like you when it starts to climb past 750 that when the air gets shut completely down and blower goes on low and then I just keep and eye on it. My liberty was cruising at 750 last night with the blower on low and the front and middle air tubes where getting pretty red so I get out my two pieces of tin foil to cover the air intake holes and that brought her down to 650

Click to expand...

how do you make your tin foil stick to the air holes without falling off?

jeff_t said:

Sounds like your not so dry wood is getting dried out and off-gassing all at once. Maybe mixing in one or two of the big ones is something to try.

Check your chimney often. Things will get much easier with a good fuel supply.

Click to expand...

I see, wood too moist won't light up at lower temps but then it gasses out and blasts off once the wood gets dried more. I will mix some of the bigger splits and see what happens.