how much is too much flame?

[drewmo]

Here's the scenario: You've got a cold stove, cleaned of all it's ashes. You want to warm the house up quick, so you build a raging fire with small, dry bits, allowing you to quickly increase the size of the fire. Next thing you know, your box is full of flame and the stove is heating up quite nicely. You look to your wife, and she has a smile on her face.

But, what I want to know is, does more flame mean more heat? Or does more flame mean more heat wasted up the chimney? Does flame mean heat at all???? How do you know when heat transmitted from the stove is at it's most economical in terms of amount of wood burned inside?

(As a side note, I had a friend tell me I had too much flame the other day, and he took the liberty of dampering the stove down. Within the hour, all my coals were dead and I had a smoldering log. Took me some time to build it back up again. Obviously, some flame is a good thing.)

 

[Highbeam]

[quote author="drewmo" date="1168393710"]your box is full of flame and the stove is heating up quite nicely. You look to your wife, and she has a smile on her face.
quote]

Given the above, especially the smiling wife, I would say that you are indeed producing the maximum amount of heat in the shortest amount of time. I do the same thing to start a fire and then load larger pieces atop the somewhat burnt out kindling and hot stove to provide the long term heat. I desire a hot stove as soon as possible and see no benefit to slowly raising the stove temps as would happen if you lessened the flame. The high flame stage of starting the fire is such a small percentage of the total burn that the efficiency during this stage is of little concern.

It bugs the bajeepers out of me when someone throttles down my fire while I leave the room. If you're hot, tell me you're hot and I can adjust the fire.

 

[Roospike]

When i start a fresh fire and would like to have quick heat i run smaller splits and after the fire gets going and the splits catch fire i still turn down the damper to at least 80% after about only ten minutes otherwise instead of getting a hot stove you'll get a hot chimney.

my .02

 

[wg_bent]

I'm with Spike on this. Once the stove is up to temp to the point of secondary burn, I damper down. The stove temp increases just as fast and doesn't burn the wood as quick. A good secondary burn produces a lot of heat, and you'll notice that very little of the flame goes up and around the baffle, whereas a big primary will often go up and around the baffle and up the chinmey.

 

[laynes69]

Once the stoves up to temp, if you have an open draft, alot of heat will go up the chimney. Once I'm in the good with a charred bed of wood, I will damper down. I lose 75% of my flames, but the flames I do have will turn blue instead of dark orange. Then with a slower draft, it gives the flames a longer time and a distance to travel around the baffle. This will extract more heat this way. I used to burn it full, but in alot of cases, too much flame is a waste of wood.

 

[Mike Wilson]

I'm with Roo & Warren on this. I let it get to full flame and see secondary starting, and then damper down. My theory, in addition to what is mentioned above, is that less cold air now comes in the primary air supply, and more heated air comes out of the secondary. The reduction of cold air coming into the firebox helps to increase heat, as does the increase in secondary combustion. The secondary also reduces smoke, and thus creosote. When I am not interested in heat, and want to clean things out, I leave the air full on and let her rage for a while, then damper down and let it rage for another while.

-- Mike

 

[Highbeam]

To clarify.... Are you referring to getting the stove from zero to say 300 degrees or are you talking about sustaining the operating temp with a few small splits flaming (and wide open primary) vs. a nice stack of larger pieces glowing red(and a more closed primary)?

Getting it from zero up to decent secondary temps quickly and cleanly is best done with small pieces and vigorous flamage in my experience, then dampering down with a large fuel load to sustain the temps. So really your question has different answers depending on which phase you are referring to. Lots of flame in a cold box and less flame in a hot box is just the way it works out and is not really a goal of mine.

Imagine when the stoves had no viewing glass.

 

[suematteva]

Am with mike, roospike and warren...

 

[Corey]

I'm with those guys. I don't have any sources or specific evidence to back up, but to me, the stove is a balancing act. You need fresh air to burn the wood, but fresh air also cools off the stove and lets the heat go up the flue. You also need a certain amount of air for good combustion, but you want the combustion products to stay in the stove as long as possible to transfer heat into the stove...but you don't want them to cool down so much that they can't pull an effective draft. It's a wonder it ever works at all

My 'feeling' is that the best efficiency comes when you warm up the stove with a fire of small splits, then throw bigger splits in, let them light off, then damper down to the point where you have secondary combustion and there are blue/white flames sort of glowing and dancing in the air above the wood. This is when heat output really seems to kick in and wood consumption is low to moderate.

Corey

 

[Gooserider]

If you start seeing red parts that weren't painted whorehouse red from the beginning, you have to much flame! :lol:

I tend to run my pre-EPA monster with the door spinner and draft wide open until the blower kicks in. The door spinner sends the air in at the very base of the fire and gets things going like a blowtorch, I will go from stone cold stove to having the blower kick on (150*F snap switch clamped to flue connector on the heavy metal stove body) in about 15 minutes from a dead cold stove.

Once the blower cuts in, I start damping down. I like to get the flue pipe up to several hundred degrees (~500 or so per the surface dial thermometer) to burn out any crud buildup, then cut it back down to almost off.

Gooserider