I'm on my second day of burning our new (2019) Lopi Liberty. Never owned a tube burner before. It's been going all afternoon, but with the bypass open. I've got the air control figured out, and have to say it works well. Now I'm on to trying to get to secondary burn, which leads to my question: what should my stack thermometer be doing when I close the bypass? The stove top t'stat will remain constant, but the stack has dropped at each attempt.
Lopi secondary question
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On the Lopi stoves like that when you burn with the bypass open it will put a lot of heat up the chimney so yes it will drop when you close the bypass. What are your temps? The flue should be around 250F and stove top around 600F. I have a Liberty insert I only use a stove top thermometer not a flue temp. I will say the Lopi stoves with that design seem very finicky with wood that is not dry enough.
The current manual indicates bypass closing within 3 to 5 minutes of closing the loading door on start up. I've seen a Liberty bypass plate assembly warped terribly. I know for a fact that unit had been operated with the bypass used incorrectly (open when it should have been closed). Food for thought.
The bypass is only opened for starting a fire. It should be closed soon after the kindling is going. With the bypass open, the stove can not function correctly and secondary burn will not occur. All the heat is heading straight up the flue pipe and being wasted. When the bypass is closed the smoke and wood gases are slowed down by having to go around the baffle. This encourages more complete combustion. Yes, the flue temp will go down, that is a good thing. As the fire grows stronger and the primary air is closed down, the vacuum of the draft pulls air through the secondary tubes. This burns excess wood gases which creates a lot more heat.
Take a moment to read the "Starting a Fire"thread up in the stickies section. It shows what is happening temperature-wise as a fire progresses.
Take a moment to read the "Starting a Fire"thread up in the stickies section. It shows what is happening temperature-wise as a fire progresses.
You can, especially if draft is marginal, but it is not necessary with a good draft.
Winds up to 50 mph cancelled today's experimentation, but we'll try again tomorrow after work. I did get secondary with a stove top temp of 600, but the stack t'stat drop had me worried. I'll take it off or ignore it and just watch the stove top temps. As for 3 to five minutes to close the bypass, I don't see how you could achieve the necessary temps. Hell, you could still have newspaper remnants burning. My manual says you may have to leave bypass open up to 20 minutes.
The bypass connection to the necessary flue temps is a false correlation. Draft varies with the difference between indoor and outdoor temps. Yes, you might need to keep the bypass open when starting a fire on a 50º day so that when you go to add wood, smoke doesn't spill out if there is just a 15' flue. But with a 25' flue and outside temps below freezing that most likely would be unnecessary. The objective is to get the firebox up to proper temp asap, not the flue temp.
Does this stovetop temp vary wildly by stove? I have the Revere and if I have good dry wood I can get a pretty good secondary burn with very little primary flame and clean glass at about 475 stovetop temperature. I see the Liberty that the OP has does classify ~600 as a medium burn though. I do agree with you on the wood, unless it's bone dry, it's kind of a pain the butt.
I'm sorry I said Liberty I have a Freedom insert I can't answer that but I don't think I have been over 650 with it on low burn I do get soot on the window but not at 600
The Liberty is a free-standing stove with a step top. It is possible to get higher and more accurate stovetop readings on the step than one might see with an insert.
I have a revere that sticks out a bit from my old fireplace, I just use a laser on it but it seems to be burning real efficiently at about 475 with clean glass. Are you guessing that it's probably just actually hotter than that?
I've made good progress with the Liberty the past few days. Tonight's startup was 15 minutes to 600 stovetop temp and the closing of the bypass. It held nicely with four splits before starting to fall off after nearly two hours. Unfortunately, I had all my wood cut to 18" before we got the stove. Therefore I have to load east-west and re-split some for a tighter fit for an overnight burn, which is this weekend's big trial.
Begreen, you recommend reading the stove top temp on the upper tier ? Do I read that correctly?
Begreen, you recommend reading the stove top temp on the upper tier ? Do I read that correctly?
It'll be hotter up there. I think I would try on the sloped face for an average stovetop temp, but the stove pipe temp is more telling about how the stove is running.
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