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Post in 'The Boiler Room - Wood Boilers and Furnaces' started by huffdawg, Jan 6, 2013.
What size do you chop your splits to?
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About 5 x 4 inches unless it's a knot that sits there and laughs at me when I try to split it. Then it goes on top of the load and disappears.
I used to make most of my splits REALLY large (almost couldn't get them into the stove), thinking I was doing myself a favor. Then I found this site and I've found out that wood doesn't season as fast or consistantly when it is left in big splits or rounds. Since then, I make most of my splits around 4x4 or 5x5 inches. That helps them season out faster, and it also allows you to pack more in the stove on reloads.
I do, however, make some larger splits (mainly with the silver maple and locust), my main reason for that is the NZ3000 fireplace I just put in. I like to throw a big split in there, every couple of hours, gives off a nice 'ambience' fire, and also throws out a lot of heat. But that said, all of my wood has a minimum of three years to season so those large splits have lots and lots of time to dry out.
I have a mix but I like to keep things 6" or less.
It drys better, it's easier to handle and it stacks better. That was even before I got my Tarm.
Drives my Dad nuts, he likes some big chunks for his furnace. I guess we're going to have to do a better job sorting who gets what.
I usually split mine down to about 4" x 5" on the end, but I've found I can burn some good size stuff if I put a large piece on the very top.
That's what I've found too. Get things rolling with the smaller stuff then pile on the big stuff. So far so good.
I'm going through some big poplar splits right now, probably about as many BTUs as a oak kindling.
I find that for me, 'playing card' seems to be about right for solid hardwood - around 4". I do softwood and poplar a bit bigger.
Too big and it won't maintain full gasification as well. Too small and it will generate too much wood gas and 'puff'.
Now that I'm controlling combustion temp it seems that I can tolerate a wider range of wood types and sizes.
I have had the puffing also but it didn't dawn on me that my splits were half the size as normal and that's what was causing it
What is "puffing"?
My best understanding is this: If you have wood that's too dry and too small, it will outgas too vigorously and cause explosions in the primary chamber. Too little primary air makes it worse.
I think of it as the amount of wood surface area available to burn. Really dry softwood needs to be larger to avoid this problem, probably because it burns faster.
I don't want to jinx my self here but I've never had a problem with puffing or bridging and that with all sizes of splits.
I'm not sure if it's a design thing or just plain luck. I've burned very small splits and very big splits, although I do try and mix the load up.
For the fun of it (I guess it doesn't take much to entertain me) I stuffed my firebox full of large splits last night and let 'er go. I really packed them in too.
It did bridge but it was still gassing, not quite as intense as normal but I did have secondary combustion. I knocked the pile down and she took off.
So it can happen and it's probably happen in the past with out me knowing it. I guess the performance wasn't hindered enough that I noticed.
I usually keep an I on my chimney while firing and when it bridges I go and knock it down. The wife never looks . She burns less wood than I do.
If I weren't obsessively monitoring secondary combustion temperatures I wouldn't realize what was happening either.
Nofossil where do you install your stack pyrometer.
I have three thermocouples - two in the secondary chamber off to the side and away from the actual flame, and one in the flue right at the back of the boiler. I use them as follows:
Secondary combustion #1 - used for blower control
Secondary combustion #2 - used to provide a readout of combustion temp at the boiler
Flue temp - used to detect fire starts
I also look at flue temp as an indicator of when I need to clean the HX tubes.
Can't find any pictures just now - I'll take some more when I get a chance.
How often do you need to clean the hxtubes.
Two or three times per season. I've only had it six years so I'm still learning ;-)
Now that I can get more stable combustion and flue temps by controlling the fan, I should be able to see differences from cleaning the HX tubes more easily. Usually I only have fly ash. Last year I ran most of the season with the primary air set too low and I had some harder deposits that took some scraping to remove.
I recently replaced the original turbulators with 3/8" chains.
I ran them for about a week and thought I would take the cover off and see how they were hanging in there.
Well they were hanging ok, but I was surprised at the amount of ash on the tubes already,since I had cleaned the tubes when I installed the chains.
Do you think that you get an initial layer rather quickly,then it gradually builds over time?
It is so simple to clean the tubes now,pull one chain out,brush that tube,move the next chain over,brush that tube,and so on.
Anyways I think I will be brushing the tubes every other week or so.
It's about once a month for me. My stack temps pretty much tell me when it's time.
Here's my tubes and turbulator after more than a month - just a very light fly ash coating. I have an older Eko with home-brew turbulators.
How does the plate seal on the EKO? Do you use silicone?
I have noticed ash build up around the top of the tubes. I wonder how muc that layer of ash effects flue temp and or heat transfer?
The plate just has a fiberglass rope gasket. There's enough draft that it's a negative pressure under the plate so no leakage even if you opened the plate a bit.
The ash on the horizontal surface builds up immediately. There's very little surface area there so I don't worry about it.
The big deal with the Eko 25 is that it's very short top to bottom, so the HX tubes are really short with not much surface area. If I were designing a boiler, it would have an Eko 25 sized nozzle but an Eko 40 sized firebox and correspondingly longer HX tubes.
According to the New Horizon catalog, all Ekos take the same size nozzle. But I agree with you. The tubes in the 25 are only about 20 inches long. I think it makes enough heat to support longer tubes. If they were another 5 inches long, I think I could wring out more heat without any adverse effects.