false wall

[steve J]

Last year was first year with new evaporator and I built a false wall without a lot of thought.But I think I may not have built it high enough or far enough back. The back of the false wall was 6 to 7 inches in front of the stove pipe connection and I was probably 6 inches from bottom of the pan. Any thoughts on this?

[Haynes Forest Products]

Man this is when a picture is worth a thousand Maple Trader Threads. Most false walls I build are floor to celing and have a grow room behind it:o

[maple flats]

For a woodburning stove single wall stack you must be 36" from any combustible surface. I don't know if you burn gas or oil. The 36" can be reduced by layers of tin or other non combustibles. To do that the tin must be spaced out 1" on non combustible spacers, doing this cuts the requirement in half, do it a second time, again 1+ and another layer of tin you again cut it by 50%. Thus, no tin=36", 1 layer=18" and 2 layers=9" and 3 layers =4.5". So if you have the wall 6 or 7" away you need 3 layers, each spaced on 1" non combustible spacers. The issue is not when the wall or combustible is new, but over time the heat drives out wood gases and will create charcoal. Charcoal ignites at about 300 degrees, your stack can be over 1000 degrees.

[3rdgen.maple]

Guys I think he is referring to the ramp he built inside his arch. Without knowing what size arch or what kind of pans we all will be shooting in the dark on this one, but the basic setup is the ramp starts at the end of the firebox and angles back toward you sap pan and ends about 10 inches from the begining of the sap pan, minimal clearance between the top of the ramp back is good, no more than say an inch and then depending on the arch or if its a flat pan or drop flue pan or raised flue pan you might have to have the ramp drop back down before the stack to let gasses escape. But more details on the setup would help alot.

[C.Wilcox]

The real test for whether that arrangement is right boils down to how well the back of your pan performed (pun intended of course). Did the back half of the pan boil well?

[Cake O' Maple]

Man this is when a picture is worth a thousand Maple Trader Threads. Most false walls I build are floor to celing and have a grow room behind it:o

Bwahahahahahahaha!!!

[maple flats]

Sorry, I mis-understood the question. If you have A Mason evaporator, ask Bill Mason. If the directions that came with it don't say, he can clarify. I now believe you are either asking about a ramp or a wall behind the firebox, whichever design Bill suggests. Bill is the expert on his products, and he is a member on here.

[Ed K]

I have been fighting with this question every yr since I bought the setup.Last yrs experiment was to ramp up to the raised flue,right up to the bottom of the pan.I filled in with brick and sand to 4" of the end of the flue,about 8" from where the stack go up.
This didn't work,think I chocked it way to much. This is why I'm rebuilding the arch to use air injection,air under-air over.

[foursapssyrup]

on our 2x6, with flat pans, we had the best boil on our sap pan with the "false wall" built about 6 inches from the back of the pan, leaving ~3" to the bottom of the pan. this can vary with each setup (raised flue, drop flue, how much wood you put in, how much draft you have, what size flue you have, etc. etc.)

you could lay the false wall without any mortar (if its bricks) about halfway down your sap pan, and then move it back a little at a time to see what gives the best results.

[3rdgen.maple]

And dont forget stack height will effect how well the arch draws air. Now does Bills arches not come with the ramp or wall already setup on them? If ones running flat pans a bigger space under the back pan would be necessary as there no passage for the gasses to go through the flues, if your running flues the closer to them the better and I stand strong on the statement that a ramp angled up from the end of the firebox to the about 10 inches back from the front of the sap pan is a great starting point if not the ideal setup.

[Haynes Forest Products]

My arch doesn't have a false wall because it was built to the desired conture. Now if you build a box and then reconfigure the inside of the arch to the needed specs then I guess a false wall or BAFFLES would be needed.

[maple flats]

When I first did the wall on my 3x8, I went up straight to 4" below the pans, then sloped up to 1/4" below the flues in about 12' distance. Too fast, too high. It forced so much heat to the top of the wall, before the ramp that I had to slow the fire or the geysers would not stay in the pan. I got lots of sweet out the hood drain because the geysers landed in the hood gutter. The next year I lowered it so my wall now ends 6" down and the ramp is the same angle. Works good now.

[steve J]

Sorry for the confusing yes talking about a false wall in evaporator mine is a 2x4 with blower. The unit has a fire box approx. 2 ft deep then a stright wall that goes up about 8 inches then flat floor back to the back of the evaporator. Its a flat pan.

[3rdgen.maple]

Sorry for the confusing yes talking about a false wall in evaporator mine is a 2x4 with blower. The unit has a fire box approx. 2 ft deep then a street all that goes up about 8 inches then flat floor back to the back of the evaporator. Its a flat pan.

Okay Im back to confused again. Sorry but I guess Im not understanding what you are asking at this point. Your arch has a wall and is goes up to 8 inches under the pans right? So what are you asking? Did your arch not come with the ramp/wall and you had to build it yourself? Are you asking if this is right? Let me ask this how did it boil and what GPH did you get out of that setup? I think without the GPH and how well it boiled its hard to say if it can be improved or not. Off the top of my head 8 inches might be a tad bit much on the flat pan. Best thing to do is experiment and throw a row of full bricks on the top and get it down to 6 inches and see if your gph goes up or down. Then proceed from there.

[steve J]

There is no ramp there is a fire box then short wall of 8 inches then flat bottom back Like a step on a stairway. That flat to the back is 2ft in length and its 10-12 inches below the bottom of the pan. I was averageing 14 to 15 gal per hour with blower half throttle if I ran at full the stack got cherry red at the elbow. I did build a false wall last year but it was thrown together hastly.

[Stamford sugarmaker]

Your 2 X 4 sounds very similar to the one I just bought and I'm trying to figure out the best way to firebrick, etc.

I think from what I've been reading is that you only want about one inch clearance through the "tunnel" that goes from the back of the firebox to the stack. You describe what I'm calling the tunnel as being 10- 12 inches below the bottom of the (back) pan. I'm thinking if there's only about an inch of clearance all the way through you wouldn't need a false wall. You could fill in the vertical space of the tunnel with firebrick and sand, and leave about a one inch gap. I hope that makes sense, folks who have done something like this please point out the error of my thinking if need be!

How were you able to control the speed of your blower? That seems like a good idea to me. My arch doesn't have an elbow, it just goes straight up.

Peter

[steve J]

I put a 3 speed switch on the cord to the blower and ran it on the 2nd speed a high was to hot for stack.

[Brent]

take a look at the instructions on Leader's web site for thier Half Pint evaporator. They detail where the wall should be and what height.

[rookie]

How were you able to control the speed of your blower?
Peter[/QUOTE]


mine is a switch designed for a table lamp as a dimmer, you have infinite control. it plugs into the wall and the blower plugs into that