rule of thumb for bricking under raised flue

[PerryFamily]

What is the rule of thumb for bricking up under a raised flue pan?
How much pan is open before the ramp ?
How much space between the rear dam and the Stack?
Its a 5' raised flue pan.

[Scribner's Mountain Maple]

Not sure I know for certain, but did insulate mine this spring and it worked great.

I didn't use brick though, I used vermiculite, and ceramic blanket. I have a 10' flue pan and left about 15-18" of the pan open to the ramp from the firebox. Then about the same amount of space in the rear to send the heat down and up the stack.

I think you wouldn't want less than 12" of space open to the firebox. Then another 12" to the stack. Leaving 3' of space to fill in the middle. That is where the vermiculite and blanket came in. I also used chimney tile, 8" to create a space on either end of the flue that would act as the high point of the ramps and hold the vermiculite. When filling with vermiculite, I let it overflow a little creating a nice slope. I then covered that all with blanket and secured it down with bricks.

Blanket is expensive, but so are bricks. However, blanket is light and bricks weigh a ton.

You may get some better information, but this worked fine for me and felt it was very easy to do.

Ben

[Flat Lander Sugaring]

no need for bricks they dont insulate unless you plan on using a flue brush which I dont think you can because its a raised flue.
When I built my arch I went around to the dealers and measured points in their arches went home and built mine. Find a dealer who has a raised flue hopefully with the syrup pan off and start measuring it.

[PerryFamily]

W rig I bought is already bricked but I think its wrong. I think the "gap" in the front is closer to 2',With the raised section at 2' and the rear @ 1'.
My 2x6 was 1' , 2'6" , 6" and it boiled hard.
I want to change it before it goes in if its not right.

[PARKER MAPLE]

The rule of thumb I have used for the last three arches I have had is take the size of the rear flue collar for the stack and that is the opening you need under then pan in the back. As for the for the front. Then it should be right up tight to the under side of the flues to force the fire up and inside them. Do this and the sap will be jumping out of the pan lol. Come look at mine if you want..

Parker Maple