Changed Nozzle in EKO 25 This morning

[Fred61]

Last evening when I was raking the ashes out for my daily burn I found a piece of cement in the ashes. Curious as to where it came from I looked into the lower chamber and couldn't see any thin out of the ordinary. Of course it's difficult to see in there with the U blocks in the way so I reached up through the nozzle and felt a lot of ragged edges. Fearing that the nozzle had eroded the sides enough to cause erosion on the refractory block itself, I decided to replace the nozzle today. I went ahead and lit my fire anyway.

Fearing a big job ahead of me I started on the job about 9:00 AM. That's first thing in the morning for me I removed all the ashes and vacuumed all the dust out and upon inspection I decided the best course of action would be to chip the old one out. It was still surprisingly tough but once I got a good crack along one side I was able to wiggle and crack the remaining portion and remove it.

Upon inspection I found something I didn't expect. The nozzle actually mates up with a shelf molded into the refractory. I don't know why it's there but I can only assume it's a dam to stop any secondary air from taking a shortcut instead of entering the throat of the nozzle. It's certainly not needed to stop the nozzle from falling through what with the extreme taper. I concluded that the piece of refractory I found in the ashes was a piece of that shelf

Anyhow, with advance warning from info picked up here I knew more or less what I was facing. The single plane taper was obvious wrong but I first needed to try the fit in the well and it protruded above the refractory about an inch. I set up a rip fence on my wet saw and trimmed the nozzle on all four sides. Left and right dimensions came out fine but it was too long for the opening by quite a bit. This meant I needed to grind off both ends in order to stay lined up with the secondary air openings.

Everything fit fine and I had all the tools picked up by 11:30 and I'm happy with the results

 

[Fred61]

Sorry about the duplicate photos but you're dealing with a senior citizen here.

 

[rkusek]

Nice work. Your old one looks more worn than mine but I'm getting a lot of small coals falling through. I'm still thinking of trying just the patch job. Are your u blocks original?

 

[Coal Reaper]

why cant they sell these things to drop right in without "cut as needed"? appears there is a chamfer for secondary air channel to account for misalignment. looks good but where is the before picture of the old nozzle? what is the dimensions of the nozzle "slot"?

 

[Fred61]

Actually you're not looking at my old nozzle in the photo above. My old nozzle is laying in the bottom of a bucket in pieces. The photo is of the cavity that receives the nozzle. I took it to show the deterioration of the shelf below.

Yes, my U blocks are still the originals.

 

[Fred61]

why cant they sell these things to drop right in without "cut as needed"? appears there is a chamfer for secondary air channel to account for misalignment. looks good but where is the before picture of the old nozzle? what is the dimensions of the nozzle "slot"?

Dunno! I cut the chamfers in the secondary air channels with the angle grinder for peace of mind. I probed around in there and everything appeared to line up but I wanted a little more assurance. I felt that cutting the chamfers wouldn't have any negative effect on the life of the nozzle. I meant to mention that in my original post.

I forgot to photograph the old nozzle before removing it. It actually didn't look as bad on top because I had protected it with the brick overlay for the last three seasons however there was erosion taking place further down in the throat contributing to the erosion of the shelf.

 

[Donl]

Would it be easier to just pour a new one in place? Has any one tried to do their own pour? What refractory cement is best for the job. Others have fabricated steel plates to protect the refractory slot from deteriorating. How is that working out?

 

[Coal Reaper]

Dunno! I cut the chamfers in the secondary air channels with the angle grinder for peace of mind. I probed around in there and everything appeared to line up but I wanted a little more assurance. I felt that cutting the chamfers wouldn't have any negative effect on the life of the nozzle. I meant to mention that in my original post.

and here i thought THEY did something smart!

 

[Fred61]

Would it be easier to just pour a new one in place? Has any one tried to do their own pour? What refractory cement is best for the job. Others have fabricated steel plates to protect the refractory slot from deteriorating. How is that working out?

This process has given us plenty to talk about but in reality it wasn't that difficult. In my mind, pouring one would be more difficult and time consuming.

 

[Tennman]

Fascinating to see the difference in design from the BioMass. The nozzles are similar but the four side plates on the BioMass are about 1" thick resting on the steel manifold feeding the nozzle injector ports. In my early seasons I had a good nozzle but crappy wood. Got it all going this season (except my storage sadly) but amazing difference. I'll always use something now to protect that crisp nozzle opening... We'll see how long the steel plate lasts. You planning on fire brick, steel or something over that new nozzle? I had to use a hand grinder to trim my new nozzle but not a big deal once every five years. You should see a big improvement in performance. Good job on all the pics showing the process.

 

[Tennman]

Agree Fred on casting your own. Those injector ports really complicate the casting process on a relatively inexpensive part.

 

[Fred61]

You planning on fire brick, steel or something over that new nozzle?

I positioned a new cut out brick overlay to protect the opening but I learned and I hope others learned from my experience that erosion is still taking place further down in the throat.

 

[mr.fixit]

Dunno! I cut the chamfers in the secondary air channels with the angle grinder for peace of mind. I probed around in there and everything appeared to line up but I wanted a little more assurance. I felt that cutting the chamfers wouldn't have any negative effect on the life of the nozzle. I meant to mention that in my original post.

I forgot to photograph the old nozzle before removing it. It actually didn't look as bad on top because I had protected it with the brick overlay for the last three seasons however there was erosion taking place further down in the throat contributing to the erosion of the shelf.

That shelf you refer to looks like casting overcast from when they cast the refractory that surrounds the secondary air tubes.
The upper curved firebrick looks separate from the rest,anyone know if you can buy these?
With the overlay over the new nozzle,it should last considerably longer.

 

[Fred61]

That shelf you refer to looks like casting overcast from when they cast the refractory that surrounds the secondary air tubes.
The upper curved firebrick looks separate from the rest,anyone know if you can buy these?
With the overlay over the new nozzle,it should last considerably longer.

That's a possibility. That shelf serves no function in my mind. I would say the guy to ask about the "curved firebrick" would be Zenon. I had always assumed that the refractory was cast in large chunks and installed in sections. Thanks for pointing that out. If they can be replaced it gives me more confidence about the life of the boiler barring corrosion or fractured welds.

 

[stee6043]

I fear I may have to just buy a new boiler if/when my nozzle gives it up. I surely do not have the tools to cut a new nozzle on-site. Knock on wood....mine has shown minimal wear so far in 6 seasons +/-...

Cool thread though. Thanks for sharing!

 

[Fred61]

I fear I may have to just buy a new boiler if/when my nozzle gives it up. I surely do not have the tools to cut a new nozzle on-site. Knock on wood....mine has shown minimal wear so far in 6 seasons +/-...

Cool thread though. Thanks for sharing!

Tile wet saw: $88.00 at HD. Good tile saw didn't even work, Four inch diamond blade for angle grinder: $2.75 at junk tool stores. I think you just want a new boiler. Didn't we catch you swooning over one of these high end boilers a while back?

 

[huffdawg]

Where do you position your u-blocks tight against the back or do you pull them forward a few inches?

 

[Fred61]

Where do you position your u-blocks tight against the back or do you pull them forward a few inches?

I have them pushed all the way back but every time I look at them I think they should be pulled forward but I don't do it because I have my reservations on that location also. I've considered, and I might do this sooner than later, removing one block and centering the remaining one directly under the nozzle. The only logic I've used when having them all the way back is that most of the heat won't be concentrated on the fire tubes in the center.

When the blocks are free of ash I can squint down the center and see about a 3/8 inch gap between the bottom of the U and the bottom of the firetube housing. For all I know, I'm now starving the center fire tubes of heat.

I assume you are as confused about this as I am. Is that why you asked?

On the units with two nozzles, do they line up three u blocks or how to they get positioned?

 

[huffdawg]

Ya I had them pulled away from the back but it seemed ash would build up and then block the 2 centre tubes.. but it might have been because my chain turbs were too long . I just cut 3 links off each turb with my new plasma cutter. (great tool ). I have the u-tubes pushed to the back now.

 

[ihookem]

What does a bad refractory look like? Does anyone have a pic of their bad ones? Mine doesn't look so good anymore but not sure it need replacing yet. Also, how much are they? How long did it take to replace?

 

[huffdawg]

When I replaced my first refractory bricks, they were cracked and broken into about three pieces each. One of my current bricks has a crack in it but has not broken apart yet

View attachment 122029 View attachment 122030 View attachment 122029 View attachment 122030 Last evening when I was raking the ashes out for my daily burn I found a piece of cement in the ashes. Curious as to where it came from I looked into the lower chamber and couldn't see any thin out of the ordinary. Of course it's difficult to see in there with the U blocks in the way so I reached up through the nozzle and felt a lot of ragged edges. Fearing that the nozzle had eroded the sides enough to cause erosion on the refractory block itself, I decided to replace the nozzle today. I went ahead and lit my fire anyway.

Fearing a big job ahead of me I started on the job about 9:00 AM. That's first thing in the morning for me I removed all the ashes and vacuumed all the dust out and upon inspection I decided the best course of action would be to chip the old one out. It was still surprisingly tough but once I got a good crack along one side I was able to wiggle and crack the remaining portion and remove it.

Upon inspection I found something I didn't expect. The nozzle actually mates up with a shelf molded into the refractory. I don't know why it's there but I can only assume it's a dam to stop any secondary air from taking a shortcut instead of entering the throat of the nozzle. It's certainly not needed to stop the nozzle from falling through what with the extreme taper. I concluded that the piece of refractory I found in the ashes was a piece of that shelf

Anyhow, with advance warning from info picked up here I knew more or less what I was facing. The single plane taper was obvious wrong but I first needed to try the fit in the well and it protruded above the refractory about an inch. I set up a rip fence on my wet saw and trimmed the nozzle on all four sides. Left and right dimensions came out fine but it was too long for the opening by quite a bit. This meant I needed to grind off both ends in order to stay lined up with the secondary air openings.

Everything fit fine and I had all the tools picked up by 11:30 and I'm happy with the results

View attachment 122029 View attachment 122029 View attachment 122030 View attachment 122029 View attachment 122030

I have found a few chunks broken off from the top edge of the refractory liner inside of primary chamber.
.

 

[Fred61]

If you're talking about the U blocks I would just overlook the looks of them and evaluate in my mind whether they are doing the job for which they were intended.

 

[rkusek]

Mine are also deteriorated but I last moved them 3 years ago during a thorough cleaning during which I caused a hairline crack in one of them. I have not moved them since and instead use a shop vac to clean behind them. Both my U blocks and nozzle are in bad shape now and will be replaced after this season. Is anyone using the fire bricks were mentioned in another thread?

 

[rkusek]

I've read about the nozzle change outs, patch jobs, the pour in place that others have done and shared here. I surprised nobody here or even the boiler makers have not cast a nozzle with a T shaped drop in "wear item" replacement to make this much easier and less costly to keep the boiler at peak performance and reduce the ash generated. Instead of the steel inserts brick overlays the T shaped wear item would cover all the wear that occurs on the bottom side too.

 

[mr.fixit]

I cast mine in place and it really went good. Next time I am going to do it when the refractory mix can cure longer. I poured it one day and only let it cure 2 days before firing. It's holding up fine but the edges around the nozzle opening are wearing a bit.

Also next time,instead of 3/4" foam to form the opening I am going to use 1". The 3/4" opening is a bit narrow,its difficult to sift the ashes down when cleaning. The narrower opening does put out a nice tight flame though!