Oak nozzle erosion on EKO 40

[mr.fixit]

This is what the nozzle in the EKO looks like after a pre-season clean-out. A little more erosion than I would like to see.
This is going to be the 3rd season on it and 90% of the 10 cords of wood a season was oak.
Also I should note that during the heating season this thing runs almost nonstop (heating over 4000 sq. ft. in 4 different buildings)
So to try to extend its life I cut some standard firebrick and formed a new nozzle opening in the upper chamber.
So far on the couple times I've burned it this way it works fine,maybe even a little better but with the width of the nozzle narrower (maybe closer now to what it was when new)coals don't seem to fall through as easily. Any way we'll run it this way for a while and see how it goes.
Also I shot a picture of one of the lower chamber blocks. They were replaced at the beginning of last season.Next time I will cast my own or try to make something out of standard firebrick that you can buy locally.
To you guys making your own boilers,Make the nozzle and refractories Easy To Replace!

 

[timberr]

Did you leave ash in your firebox sine last burn season? Last season was my 3rd with a Eko 25 I usually clean out the fire box 1/month during the season. And th nozzle looked pretty good. This past spring I let the ash sit in the firebox for 4 to 6 weeks (lazy..) when I finally got around to cleaning out the firebox I noticed deterioration around the nozzle that I swear wasn't there the last cleaning.

I am wondering if some moisture and wood ash is acidic and causes the problem. Personally I won't be lazt again.

Any thought out there?

 

[mr.fixit]

No,I don't leave alot of ash in it. I use the boiler on and off during the summer for DHW when the solar is lacking so I don't think the ash does it.
There has been post on here about oak and corrosion but I couldn't find them. If I remember correctly one manufacturer discourages the use of oak.
Now ,I believe some erosion is normal especially with heavy use. Pretty hostile environment in there.

 

[Clarkbug]

Here is the one you are thinking of:

https://www.hearth.com/econtent/index.php/forums/viewthread/52943/

They dont discourage the use of oak, just the burning of any oak that hasnt been completely seasoned. Any moisture left that is burned out is acidic, and can lead to the nozzle wear. How long was your oak seasoned for?

 

[mr.fixit]

That's the thread I was thinking about. Thanks Clarkbug.
The first season I did have some that was only seasoned 1 year,but last season everything was seasoned 2 years and 20%mc or less.
I noticed little erosion the first year(if memory serves)but should of took a picture when the boiler was new so I had something to go by.
The original lower blocks didn't erode,they just cracked into several pieces and it made it difficult to remove them to clean the ashes.
Like I stated earlier this thing has had 20+ cords go through it in 2 years.That might be 3 or 4 years of use for someone with less heatload.

 

[woodsmaster]

Mr fixit What did you use to cut the brick?

 

[mr.fixit]

They cut easily with a diamond blade in a small angle grinder.
I think I got the blade at Menards for under 20$.
It helps to trickle some water on the brick as you cut it.

 

[woodsmaster]

Has it seemed to help with the erosion ?

 

[mr.fixit]

Won't really know for sure until I remove the firebrick overlay, but I think it helped alot.
The fire brick shows some erosion so I believe it's taking the brunt of it.
Now I wish that I would of done the overlay sooner.
I'll see if I can get a picture of the firebrick now.

 

[mr.fixit]

Here's a picture of the firebrick overlay today.Some erosion on the edges and and minor surface flaking on a couple of the bricks.It's had approx.5 full cords of wood go thru it since the firebrick install in Sept.
I plan on replacing the firebrick overlay at the beginning of each heating season,to extend the life of the factory cast in place nozzle.
Really now not so sure that the oak has so much to do with the erosion.

 

[Medman]

I am noticing the same erosion on my EKO 25 now, and I burn less than 10% oak. I think its just the nature of the refractory. I plan to install your firebrick overlay at the next full cleaning, whenever it gets warm enough outside to have the boiler down for a day.
Any difference in performance with the new brick installed? I am thinking my unit will run a bit better since so many of the large coals now fall down through the widened nozzle.

Ryan

 

[mr.fixit]

Medman,I think the boiler works just as good if not better.
With the new nozzle slot slightly narrower and shorter (probably even than when new)less coals fall through and I can run the fan @ 50% and still get smoke free burns.I could never do this before at 50%,always had to run at least at 60% fan speed.
It seems to be easier to get gasification going when starting also but this may also be due to experience on my part.

I suppose the actual btu output is less with the smaller nozzle but it's hard to tell with this mild winter, and the boiler has been keeping up just fine.

 

[ohbie1]

Mr. Fixit, I saw your post in Sept. and my nozzle was pretty worn. Following your idea, I lined the bottom of the upper chamber with fire brick. It has worked great this year with no noticeable wear to the brick. The brick was about $20 as compared to $300 for a new casting. So let me take this opportunity to say THANKS for sharing that idea.

 

[mr.fixit]

You are welcome,ohbie

 

[Adios Pantalones]

Did you leave ash in your firebox sine last burn season? Last season was my 3rd with a Eko 25 I usually clean out the fire box 1/month during the season. And th nozzle looked pretty good. This past spring I let the ash sit in the firebox for 4 to 6 weeks (lazy..) when I finally got around to cleaning out the firebox I noticed deterioration around the nozzle that I swear wasn't there the last cleaning.

I am wondering if some moisture and wood ash is acidic and causes the problem. Personally I won't be lazt again.

Any thought out there?

Wood ash is actually highly basic, not acidic.

I cut a lot of firebrick for kiln building and use a diamond blade in my worm drive Skil Saw. I highly suggest soaking bricks in water for 15-30 minutes first- it helps cool the cut and keeps dust down. Wear a mask and EAR PROTECTION. Man is that loud.

Super Duty firebrick will withstand erosion much better than High Heat Duty. I assume there's no issue with swapping between the types, but I would check first- super duty conducts heat better than high heat duty.

 

[woodsmaster]

Good tips. Thanks for sharing.

 

[barnartist]

I have the older style EKO 60. It has a flat (not tapered) upper chamber. I want to try and put a layer of firebricks into that chamber, my nozzle is worn down to the inner air intakes (the secondary air). I have seen that the new nozzles do not fit the openings from the factory, so I am just trying to see if I can avoid that project for now.
In using the layer of firebricks and raising the wood level off the nozzles by the width of the firebricks, does this still mix the air correctly for the gassification process? You all must be happy with it so I am guessing that is a yes.
I am growing tired of all the good coals falling through the nozzle before they have been fully consumed.

I see this post is older now, so Id like to hear some updates on how the firebricks have held up for you all.

 

[Fred61]

There's another thread running parallel with this one titled EKO 25 nozzle. A few testimonials on the success of overlays there too.

It's interesting how some folks have early wear on the nozzle while having less wear on the target bricks and vice versa. My nozzle showed excessive wear after three seasons but after five seasons, my target bricks look like new. As I said in the other thread, I'm starting my third season with the overlay and I haven't added any wear to the nozzle.

When I do install the spare nozzle, I will be running it through the ceramic tile wet saw to add the top angle.

 

[maple1]

I'd bet the ones with high target brick wear keep their target bricks pretty well clean of ashes.

 

[mr.fixit]

I'd bet the ones with high target brick wear keep their target bricks pretty well clean of ashes.

I leave a layer of ash on the bottom portion of the blocks,its the upper portion that take the brunt.
A well tuned boiler with a good flame,running steady most of the winter is hard on target blocks also.

 

[Fred61]

I'd bet the ones with high target brick wear keep their target bricks pretty well clean of ashes.

Actually I batch burn and completely remove the ashes from the blocks before each fire with a tool I made that has the same radius as the blocks. My thoughts are that I want to have even heat on them and not insulate the lower portion with ash while the top is completely naked causing the upper part to be hotter. As I said, they are like new at this time.

 

[goosegunner]

I sure would like to see some kind of metal cover for the nozzle to reduce wear. The Froling has a some type of metal plate for its firebox side of the nozzle.

gg

 

[maple1]

Actually I batch burn and completely remove the ashes from the blocks before each fire with a tool I made that has the same radius as the blocks. My thoughts are that I want to have even heat on them and not insulate the lower portion with ash while the top is completely naked causing the upper part to be hotter. As I said, they are like new at this time.

Well that's interesting. I leave an even thin layer of ash on mine - makes a pretty good abrasion insulator. That area is a very hostile environment for anything, for sure.

 

[Fred61]

Well that's interesting. I leave an even thin layer of ash on mine - makes a pretty good abrasion insulator. That area is a very hostile environment for anything, for sure.

This doesn't pertain to your unit but I have the fan speed spooled way down to about 50% so my flame is pretty lazy compared to probably the majority here. When I tuned it about five years ago my goal was to have the smallest flame possible and still have the nice red/blue clean flame.