Hi guys, good to be back. I have had my Jotul F500 Oslo for 3 winters, and I made a great discovery this week. In the past, when I would shut the air down, I would try to leave just a tiny (1/8" or less) gap instead of pushing the air all the way tight. I thought this would help it burn hotter. So this week, I decided to try pushing it all the way closed, with no gap at all. Great results! Much better secondary burn, and longer burn times. Love it! I guess that is the way the newer stoves are designed to run, right? Thoughts?
Pretty much! "Shut down" isn't "closed." If the wood is good, and it's installed properly....she'll burn good.
Just remember folks, all stoves and all installs are not the same. One good example is with our stove. We find that we typically have the draft much lower than others do who have the same stove. So just because one guy does it does not mean it will work for all. Experiment with it only when you can be with the stove for a long period of time, like on weekends.
^ very true! I could have a pipe length twice what you do or vice versa and draft/ burn behaviors would be muuuuuch different. Wood quality comes in to play as well. Lots to think about...
I totally agree Backwoods. Some people might need to leave a little bit of air flowing, and like you said, experiment with it only on weekends when you can keep an eye on your temperature gauge. And as always, wood seasoning affects everything. Thanks for your input guys!
Optimal burn requires different settings on my stove depending on species as well. For example, early on, pine seems to need a bit more air than gum in order to get clean burn.
"How low can you go." As a general principle, the lowest airflow you can achieve for the desired temperature (heat output) should be the most efficient burn.
Okay, normally, on my Alderlea insert, once I get it up to speed at half-way open, I can turn it down almost all the way; I "closed" it up last night, and saw not appreciable change, either in burn time or temp retention.
You can't completely shut down the air with a modern stove. In my stove the doghouse air is not affected by the primary air control, nor is the secondary air. So if I shut down the primary air, I still get air coming into the stove, and the amount of air depends on the weather and the flue setup I have. For my stove I can't shut the air all the way down without smouldering, but if I had a better flue maybe I could. For my stove I can't get much beyond half closed, but my flue isn't very good as far as I can tell.
My Jotul would run most of the time fully shut down, and still burn too hot. It'd cruise often at 700-800F on full load of bl and air closed off, so there wasn't much choice in leaving the air open unless you wanted to be overfiring. I plugged the doghouse air, but unfortunately could not access the secondary air intake so it is always wide open. But to the point of the title, unless there is specific reason to leave the air open (poor wood, or burning coals down, etc) it stands to reason the slower you can slow down the flue gasses the more heat your going to extract. Of course you need some heat in the flue to maintain proper draft and prevent creosote, etc. I'm finding my new stove to be very efficient to load it fully and throttle down to fully closed, as opposed to a smaller load run with the air open a bit more.
This would be considered the primary air, air that takes a direct path from the air intake, and not routed through a hot area to heat the air within. When you open your stove door, to the front and down, should be what guys call the doghouse.
There are the few basic rules of how things should run, but I'm in agreement with Backwoods Savage, it's not a one size fits all situation. He mentions having a lower draft, where as we have anywhere from sluggish to incredible draft, depending on the weather here. I use different air settings depending on the weather. How I burn at 40-45 F is much different even than how I burn at -20 or -30 F. You just have to be smarter than that big black steel box, and adjust for the situation. If the air is cut back, and you're getting the most of your fire, then it's where it needs to be.
Well I may be using the wrong term, but what I meant by doghouse air are the unrestricted air hole(s) that feed into the coal bed through the hump in the middle (the doghouse). That is seperate than primary air which has a control and enters from the top of the door.
Yes of course I don't think anyone is saying choking the air to a smouldering fire is most efficient (unless your talking a cat stove but even then you don't want to stall the cat). I think the main point is slowing the burn down to the minimum amount and maintaining a proper burn, will generally be more efficient. Depending on your heating demands and other factors, this may not be possible of course.
I'm guessing our stoves are two different creatures. My primary comes through the doghouse and is regulated by the air control lever.
Fully in agreement with you there. I find a flue probe is really handy to dial in that "sweet spot" for me. I tinkered with my air control lever, and now my stove is a bit more restrictive. But...I can run the stove about 75 F cooler (500-540 F) while dropping the flue probe temp over 200 F from the previous full shutdown setting.
Sorry to bring this up but isn't this basically the thing NOT to do in the case of temps this high? Im not a stove burner yet but hearing the advice of many on here, wouldn't this be best on a mixture of wood and not a straight up one species that is typically known for its hot fires? I'm only reading these history threads here to learn and do the things that don't put your stove at risk but if it was within the limits of the stove, you're good. My stove temps are not to exceed 700F so naturally I already have the info in my head to say "wait a min, full loads have not been typically good to do with one kind of wood that racks up temps" but I would guess that any full load can do that and especially if the air is wide open. To me that would be asking for trouble!I often see cruising temps between 600-800 and people close it off but then the only way that fire is going to die down is if its green. Please take this with respect intended, Im only asking because when you got your stove shut down and running that high, I wonder if that's "normal". Learning how to do this before I start doing it is better to be asking dumb "wtf happened??" Questions in the middle of Winter. My wood will be plenty dry by fall, more than enough too. Your post will educate me so I appreciate that you have said this.
