Leaky stove or too much draft?

[Troutchaser]

So how can you tell?
Extreme draft will pull air through every possible space and build the fire, right? I had some runaway fires, refitted a door and it helped. Still had too much flaming and went ahead and regasketed the doors. Still too much flaming when downdrafting. Not runaway by any means, but burning too fast, which builds the flu temps, which increases the draft, which increases the fire.
Here's the caveat. If I kill all primary air, I lose the secondary combustion within 15 - 20 minutes.

Filled the stove with smoke on a warmish day last weekend and saw smoke coming from most every corner and cranny-except the gasketed seals. Just how much air leakage should a stove have as a part of its construction? Should I try this again and pinpoint for leakage? (cleared it out quick the other day because the family was gagging). $1 test passes every time.

Still a first year burner and trying to learn. Very frustrating. You've all been helping me a lot this season.

21foot straight up pipe. 8 feet ouside and 13 inside the house.

 

[karri0n]

You seem to be relating that, with the air open a bit, the temp continues to rise.That's really not surprising in an EPA stove, as they are designed to be able to have the air turned all the way down, and continue to rise in temp or at least hold a steady temp through secondary combustion. I wouldn't necessarily condemn the stove for air leaks nor the chimney for too strong a draft in this situation. Since you had smoke coming out of the stove, it's not likely that too much draft is an issue.

The issue of the fire going out when the air is closed sounds like a fuel issue. How long has your wood been split and stacked?

I'm very surprised you had smoke coming out of the stove. That is a definite sign of either a very poor draft(not likely in this case) or a negative pressure situation. Negative pressure could also be one of the culprits causing the fire to go out when the primary air is closed.

How tight is your house? Have you tried opening a window by a crack near the stove, then shutting down the primary air? Make sure you don't have a clothes dryer, exhaust fan, or upstairs window turned on. You also said it was a warm day. Did you establish a bit of a fire to create some draft in the chimney before "filling it with smoke"?

How did you fill the stove with smoke?

 

[Troutchaser]

I have little doubt of why I filled with smoke. Weather had been warm all day (high 40's). Was cooling down at dark when I lit the stove from cold. Just had a cold pocket in the flue (actually disassembled the flue that day for a check).

My real issue here is that in full downdraft mode I don't think I'm supposed to see much flaming on the splits. But as the flue temp. increases (800-900-1000), thus goes the draft, and it's pulling air from somewhere. I can't find a cruise.
I have bought packaged wood with the same result. If it's the wood, why does it want to burn so much with just a little air? Then snuff when I completely close the primary? All my experiments here seem to get comflicting results.

As a test, I put a piece of foil with a hole in it over the air intake when it starting increasing temps last night. Suction held it in place. Eventually killed the fire. Not sure what this tells me other than the hole wasn't large enough.

 

[karri0n]

are you sure the fire is completely snuffing out when you close the primary?

I was under the assumption that the lopi is a downdraft unit, and the secondary combustion happens behind the refractory package and is invisible from the front of the stove. When the fire snuffs all the way out, do you have a thick plume of smoke coming from the chimney? If not, then it's fair to assume the stove is running in secondary combustion effectively.


Yhere's a good possibility you are closing the air down too soon if you are paying too much attention to flue temps. When you say 1000 degrees, is this with a probe thermometer? There have recently been several threads on the inaccuracy of the condar flue probes, especially in regards to them reading hundreds of degrees higher than the actual temperature. What is the stovetop temp at when you are closing down the air? It should be 450-500 on the stovetop when you begin turning the air down. turn the air down in a few stages, closing it by 50% each time - I.e., full open, stove is at 500, turn it down to about 50%. wait 5 minutes, if the flames are still going well, turn it down to 25%, after another 5 minutes, if still strong flames, turn it down a bit more until you get it all the way closed.

 

[Troutchaser]

KarriON
Thanks for the help. I came home tonight and went over the gaskets again. Cause it just wasn't making sense. Found two problems. After taking a piece of magazine paper and cutting it down to a two inch strip, I found a very loose spot in the ash pan and one door hinge side that I had just regasketed. But I remember having to stretch the gasket on that side of the door in order to get it to complete the fit. I slightly tightened up ash pan and pulled out the door gasket a little.

Two hours later I'm downdrafting. No flames. 600 stove top and 750 flue temps. Cruising.

Man I didn't think I had a gasket problem. I can't believe what a difference a little air makes.

Thank you for your kind responses. I'll still follow your advice on reducing air. It's been a he!! of a burning season.

 

[tcassavaugh]

if you don't have on in your pipe, a damper might help. i've always put one in my single wall. in my humble opinion it helps regulate the air flow even better used in conjunction with the stove controls.
glad you found the gasket problem. i konw when i have my ash pan open on my jotul it really takes off.....matter of fact its sometimes part of my starting procedure or to help kick-start it a little when i load on new wood on an old fire.

cass