EKO 40 Nozzle Erosion - first year report

mhearts,
I was looking at/cleaning my EKO40 today and have not found the erosion that you are talking about. My unit has successfully finished it's third winter heating season. I did find a small amount of erosion in the nozzle in the secondary chamber though. Be sure you are not damaging the nozzle when you are cleaning the unit. Orlan has some refractory cement you can purchase, at least that is what I have been told. Nofossil has the 25 model and has had some problem with erosion. Maybe you can do a search and get some info from him.

mhearts said:

I did my spring cleaning yesterday on my EKO 40 after one full winter of buring, I noticed in the upper chamber that around the top lip of the nozzle a substantial amount of erosion has occured and the top edge now has a radius of probably 1" to 2" . It looks guite rounded and I am concerned that after years 2, 3 and 4 the throat will be worn away . What do you guys think about this level of erosion after one year? Do those EKO 40 owners that have burnt for multiple years have more erosion or does it level off after the first year. I was thinking of installing a metal plate with a nozzle cut into it and placed in the bottom of the upper chamber to take the abuse of the erosion. Has anyone addressed this issue.

Thanks

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Metal will not stand a chance in that environment. That area is near cutting torch temperatures which is why refractory is used in the first place. A metal shield would simply be eaten up.

mhearts,
I should also have included that I use my EKO40 during the summer months to heat dhw as well. My unit has almost had a daily fire in it since Thanksgiving weekend of 07 (edit correction:06). So though I have heard of the erosion of the refractory and it concerns me I think it odd that it has happened. have you sought out a means to replace it? The main vendor to the US supposedly has the ability to get replacements.

I have a little wear on the front nozzle on the bottom. I finally figured out that the refractory is very brittle and I was wearing it down by rubbing the end of the propane torch on it. Now I'm allot more careful and not having a issue anymore.

mhearts said:

Do those EKO 40 owners that have burnt for multiple years have more erosion or does it level off after the first year. I was thinking of installing a metal plate with a nozzle cut into it and placed in the bottom of the upper chamber to take the abuse of the erosion. Has anyone addressed this issue.

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I haven't had any erosion at the nozzle, but I've lost between 1/8 and 1/4 inch of the ceramic material on the lower-chamber door, right where the flame hits it coming out of the refractory bricks. I'm somewhat concerned because the rate of damage seems to be accelerating now that the relatively shiny surface of the tile (when new) has been eroded. EKO 40, burning since October, first noticed the damage in early March. Anyone else seeing this on their door?

Just out of curiosity, mhearts, what type of wood were you burning? I have mostly burned bl walnut but I have also burned oak, pine and other woods in smaller amounts. Also I have to ask about your tuning. Don't get me wrong I am not trying to find fault or "protect" the mfg. But I am curious as to the cause for the erosion like very high btu output or pre-ignition of the upper chamber exhaust gasses, high or low moisture of the wood, that sort of thing. There are some other posts that show even higher degradation to the lower portion of the nozzle and it seems odd that one portion of the refractory is fine but another part only inches away is crumbling away. It's almost like the refractory is inconsistent in its cure or composition quality if there is not a problem in the way the unit is operating.

After cleaning the ash out of the upper chamber (I hadn't done it since January, since the manual suggests leaving the ash in there, and it was about 2" deep all around the nozzle), I found my nozzle to be intact with no erosion. Did you clean your primary chamber often this past winter? I wonder if the ash layer protects it.

I've been burning mostly red maple, with red oak, white ash, and white birch in the mix, all well seasoned. Anyone else having erosion issues with the lower door ceramic? Do people clean that off with each ash removal or just leave the blasted ash on it?

mhearts said:

I burnt mostly ash and silver maple this winter that had been cut a year in advance. It was seasoned pretty well and was intended to be burnt in my wood stove when it was cut so some was on the large size. I would say that I experienced some bridging as a result of that, only occasionally. After the first month of runnign this I had it figured out and had the fan opening closed to less than a inch and have a nice blue lazy flame coming into the lower chamber. I had not problem acheiving gassification. I do not think bridging would cause this type of problem since the gassification basically stops and the temperatures must go down when the bridging takes over. Does this look excesive to you? Would you consider a patch job to repair ?

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No you wouldn't think that the bridging is causing the erosion. It it is possible there is an issue with the refractory composition. But on a not so side note once you have the lazy blue flame you should boost the output a little to get a jetting type flame as the "lazy blue flame" is just an indicator of the (good) gas mix. Some have had standard replacement (locally produced) refractory deterioration because the fire was too hot in the lower chamber for it. Ignition of the volatile gasses is supposed to be in the secondary chamber so there is a remote possibility that you were getting ignition in the primary chamber and the primary refractory is not the same and a weaker composition as the secondary chamber. (All guess work). Since it is your first year you may have some warranty work that needs to be done to get the refractory replaced. I would not want to go into a heating season with a worn nozzle. Please keep us posted.

VeggieFarmer said:

After cleaning the ash out of the upper chamber (I hadn't done it since January, since the manual suggests leaving the ash in there, and it was about 2" deep all around the nozzle), I found my nozzle to be intact with no erosion. Did you clean your primary chamber often this past winter? I wonder if the ash layer protects it.

I've been burning mostly red maple, with red oak, white ash, and white birch in the mix, all well seasoned. Anyone else having erosion issues with the lower door ceramic? Do people clean that off with each ash removal or just leave the blasted ash on it?

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I have surface pitting on the door but nothing that concerns me at this point but I do have a vertical crack in the refractory of the door.

I've wondered if refractory life could be lenghened by metal lining. As was mentioned something like 1018 cold rolled isn't going to stand up to 2000 degree temps. I was thinking Inconel & this would need to be Tig welded. Wood Gun has some nozzle life issues also, about 2 to 3 years I've heard & maybe a jet engine alloy would help. I don't believe 2000 degrees would be any problem for Inconel. Price is a consideration though. Randy

I think recall a few posts that talked about moisture in the refractory going away after several firings. I wonder if some damage occurred at that point. I used to make pottery and have worked a bit with high temp refractory and bricks-moisture and rapid temperature rise can certainly cause problems.
I have also seen inconsistency in high temp bricks from the same factory. Some look brand new, others look a little crumbly and rounded on the edges-like the photo-after the same use. Maybe a bad batch of some material along the way.Seen that a few times with raw materials.

So now I'm wondering, if it takes a few firings to get rid of the moisture in the refractory, how much is it shrinking? Its kind of hard for me to imagine that the refractory hasn't been fired to temp prior to putting these boilers together but I could be missing something.

Noah