lsucet
Minister of Fire
Just follow their recommend way of how to burn and in no time you will be enjoying nice secondary burn. Start from scratch following their instructions.
Can be. First and foremost, check your wood, the lower the MC the better (and no more than 20% anyway!), then learn how your stove reacts when you close the primary air in small increments. The pic you posted in the other thread shows good secondaries (maybe a bit too yellow, but that can be due to wood species) and if they went out seconds after the pic was taken, you should have given a pinch of air more... that’s learning your stove, pipe, wood and weather. Don’t overthink it, as someone on the forum said... it’s just a fire, burn it!..for a second i felt a huge weight of relief when i read what you wrote
but that picture was taken at just the right time. seconds later all the flames went out completely so i definitely didnt have a secondary burn
i may be confusing what a secondary burn actually is. perhaps with the F55, the flame doesnt actually shoot out of the small holes?
I have a f55 and it shoots out the holes...in fact pretty vigorously with good dry wood but the stove can be finicky in terms of shutting down too early....the stove reacts quickly to air adjustments. It take patience. What is your stove top temp when you shut the air down? This stove requires incremental adjustments from my experience.
The flames do no actually shoot out of the holes, but the at times give off that appearance. Air comes out of those holes and quickly ignites the gases in top of firebox.i think the top is around 450F when i start to shut it down.
so you actually see flames coming out those holes?
Secondary tube stove combustion works like this: main fire burns, when the internal temps hit approx. 1,100deg f the flue gases separate above the baffle, the hotter flue gasses (complete burnt stuff) rises and goes out the chimney while the heavier cooler flue gases recycle back into the stove through those air tubs, while going through the tubes they mix with the secondary room air, once back in the hot firebox they get re-burnt completing the cycle.The flames do no actually shoot out of the holes, but the at times give off that appearance. Air comes out of those holes and quickly ignites the gases in top of firebox.
Secondary tube stove combustion works like this: main fire burns, when the internal temps hit approx. 1,100deg f the flue gases separate above the baffle, the hotter flue gasses (complete burnt stuff) rises and goes out the chimney while the heavier cooler flue gases recycle back into the stove through those air tubs, while going through the tubes they mix with the secondary room air, once back in the hot firebox they get re-burnt completing the cycle.
It is important at the initial fire to get it hot enough before shutting down the main air, 500deg stove tops work with most stoves, once you start shutting the air down the actual fire box temp will get warmer because the draft if forced to slow a little keeping more heat in the firebox, on cold stove starts with good dry wood it should take approx. 30min before you can shut it down, sometimes even longer if there is no ash on the bottom brick, (ash acts like an additional layer of insulation, minimum 1" of ash is recommended on the bottom of the firebox for normal operation)
This is not actually correct. The hot flue gases do not recycle back through the air tubes. The air direction through the tubes is one way only, there is no recirc. As the primary air is closed the draft forms a vacuum in the firebox. This draws air from the secondary air intake through the tubes. That air turbulates hot gases at the top of the firebox and reburns them.Secondary tube stove combustion works like this: main fire burns, when the internal temps hit approx. 1,100deg f the flue gases separate above the baffle, the hotter flue gasses (complete burnt stuff) rises and goes out the chimney while the heavier cooler flue gases recycle back into the stove through those air tubs, while going through the tubes they mix with the secondary room air, once back in the hot firebox they get re-burnt completing the cycle.
It is important at the initial fire to get it hot enough before shutting down the main air, 500deg stove tops work with most stoves, once you start shutting the air down the actual fire box temp will get warmer because the draft if forced to slow a little keeping more heat in the firebox, on cold stove starts with good dry wood it should take approx. 30min before you can shut it down, sometimes even longer if there is no ash on the bottom brick, (ash acts like an additional layer of insulation, minimum 1" of ash is recommended on the bottom of the firebox for normal operation)
Yea, I really butchered that one, I thought I knew what was up.This is not actually correct. The hot flue gases do not recycle back through the air tubes. The air direction through the tubes is one way only, there is no recirc. As the primary air is closed the draft forms a vacuum in the firebox. This draws air from the secondary air intake through the tubes. That air turbulates hot gases at the top of the firebox and reburns them.
Additionally, waiting for a 500F stove top temp can lead to excessively high flue temps, especially on a cold start. In our stove secondary combustion is already happening with a 250º stove top on a cold start. (On our Jotul F400 this was around 300º.) It takes time for the mass of the stove to heat up, even though the firebox is already up to temperature. Waiting too long to start turning down the air wastes fuel and can cause flue temps that may exceed the pipe rating. It's better going with flue temp than stove top temp. Start turning down the air when the probe flue temp is around 400-500º. (Surface flue thermometer temp around 250ºF) If it's not possible to read flue temp then one should use their eyes to determine when to start closing down the air.