Looking for some advice and help with my new 2x6 evaporator.

[SmellsLikeSyrupNH]

Pictures may need to be posted in 2-3 threads but I'll try my best to explain each part.

So this weekend I got my new float box and wanted to install it and get the arch setup and boil water in it so that I can clean up everything, cover it, and get it ready for the end of the winter and put this project to bed.

I purchased 2" ceramic fire blanket and my plan was to use that throughout the arch with some fire brick.

I will explain each step:

I placed firebrick against the side of the back portion of the arch and filled the evaporator with playground sand to fill in the space. the tinfoil stuff you see against the stack is actually backed with ceramic fire blanket. I thought that would help with the scorching of the back pan from the stack heat.
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I then laid the fireblanket down over the sand and against the brick and extended it down into the fire box above the port that the blower shoots its air into:
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I finished by lining the fire box with the blanket as well as placing firebrick and standard bricks in the bottom below the grates to take up space and direct the airflow upwards onto the fire from the blower. You will notice the bar of metal that would be where the 2 pans meet was a little bent, I did the best I could do to straighten it. I also put gasket around the perimeter. I placed the pans on and checked for spacing etc...it all seemed to sit pretty flush.
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I added my pans and connected my preheater rig and connected that to the float box:
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No my issues:

Not really an issue, but took about 6 minutes to get the front pan to boil once i had the fire going and turned the blower on with about 2" of water in the pan. I am happy with that time frame.
Ran the Arch for about 1 hour, in that time my far back section barely got to a boil. As soon as I opened the door to load wood, that shut right back down and took a while to come back to a boil.
The metal bar that goes between the front and back pan, seems to have melted :-( picture below
I could open the door without turning the blower off and it didnt seem to blow anything back out at me, it says its 1/45th HP. Im thinking its just too small to have a real effect on a firebox that is 24x20x29"



Ive hit my picture limit, so I will post a picture of the melted bar in a reply to this thread.

My concerns are:
Why would that piece of metal basically melt?
If the blower and fire were hot enough to cause that, why was my back section of the pan barely boiling? This also seemed to limit the capabilities of the preheater which is near the back of the arch as I wasn't getting a hard enough boil to really effect the copper. I will saw the sap was "warm" going into the float box as opposed to the cold water I filled my tank with, but I just expected more.
My stack height is the Arch connector, which I believe is 3ft, plus 9ft and is 6" in diameter. So 12ft of total height from the arch.

Thanks in advance for any and all advice.
-Scott

[SmellsLikeSyrupNH]

The melted bar.
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The evaporator boiling away
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[asknupp]

That strap that melted looks really thin from the pics. 6 mins for the front pan to start boiling is pretty decent. The blower/motor is pretty small but the way it's being explained it sounds like your blowing all the heat up the stack. Can you take a stack temp? Or even explain what's coming out of the stack from the time you start up to everytime you added wood. I have to shut blower down everytime I add or risk burning everything down. What type of blower? Also I wonder if you had a ramp from fire box extending under the rear pans might be a factor as well.

[SmellsLikeSyrupNH]

I could adjust the sand under the blanket to make more of a ramp as opposed to just being "flat" I was trying to reduce the space under the pan, so the blanket and sand idea seems to work, but I do not have it sloped from the front to the back, its pretty level.

My old evaporator with my old blower was also VERY strong, if I didn't turn it off it would blowing everything all over the place.

I agree the metal seems thin, its what came on the arch though, so perhaps I just need something thicker.

This is a picture of the label on the blower, sorry for the quality:
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[psparr]

What is the gap under the back pan? Closing it up a little might help. Asknupp, when talking about the ramp, was referring to the straight up wall at the back of the fire box. If you could angle that a little more it might help as well.
As for the back pan, you're feeding cold sap into it. That will make it hard to get a great boil there. You'll need a hood over the back pan to force the steam to heat the preheater pipes.

[asknupp]

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A gradual ramp from fire box to the back pan area.

[n8hutch]

First question did you Brick over your ceramic blanket? It looks like there is nothing protecting your back wall? Not sure what size blower you have therenough but you want probably 300 to 400 cfm. What gauge stainless steel are the pans? The look like they are a little on the rugged side. Which has its benefits and it's draw backs just like anything. Your only going to want a 1 to 1.5 inches air space under your back pans I'm not sure what you have now. I kinda doubt you are blowing the heat out the smoke stack 6" is kinda undersized for a 2x6.

[madmapler]

It looks like you could dam up the area behind the pans and before it shoots up the chimney in order to hold back some of the heat. I'd try stacking up some bricks and necking that area down a bit and see what happens. Maybe close off the middle and send it around the sides. I have auf and aof combined on a 4x12 and my opening is smaller than yours. The blower seems a little small from what I can see. I'd get rid of that piece of metal and put blanket between the pans. That's what most evaporators do.

[whity]

Looks like you need a dam about an inch past the back pan and an inch above the bottom of the pan with a slight angle to it. We keep about an inch space between our pans and insulation in back. You could use 1/4 in arch board to protect the insulation blanket also. As for the metal bar, If it has heated up and bend once it will always bend under heat. Cut it out and just put insulation between the pans. We run a half hp motor for our blower on a rheostat to control the air flow. One way we keep the back pan from scorching from the stack heat is a 1/4 arch board between the 2