GPH on a 18 X 60 drop flue?

[Zamkev]

Can anyone out there give me a rough idea what kind of gph I might expect to get from a drop flue pan set for my 18 X 60 arch? Some long days this yr have me believing that I ought to look into an upgrade from my continuous flow flat pan.

I only want to do 100 taps, so before everyone suggests it - moving up to a 2X6 is not really something that I think I ought to do. I just want to be more efficient on my current set-up.

Any insight is appreciated. Also - if anyone is upgrading and has a 18 X 60 pan set they are wanting to part with, please do let me know.

Thx!

[Zamkev]

Also wondering what the main differences are between a drop flue vs a raised flue are. Which is more efficient? Easier to clean? Easier to drain? etc etc.

Thanks.

[Big_Eddy]

I have a home built 18x60 with 6@5" drop flues. At the beginning of the season I can get 20gph - once the soot builds up I can consistently run 16gph. This is with natural draft feeding small wood every 6-8 minutes. I run 3/4" - 1" deep, shallower when its' really rocking as my float box gets behind.

I comfortably keep up with 100- 150 trees boiling 60-80 gals at a time.

I can't talk to advantages or disadvantages - I've only ever run my drop flue pan.

[Zamkev]

Thanks Big Eddy. That's a pretty decent gph. Do you have a syrup pan as well? If so, do you keep everything running at the same depth?

Also - how far are your flues from the ramp?

THanks a lot.

[Big_Eddy]

My flue pan is 18x39 and my syrup pan is 18x24 for a total length of 63". 2 lengthwise dividers in the flue pan and 2 crosswise dividers in the syrup pan.
My flues are 1" wide x 5" deep and spaced 1" apart.
I have less than 1/4" gap in the arch below the flues.

My firebox is the first 18" of the arch and the ramp runs another 16" or so levelling out about 10" into the flue pan. Nothing scientific - I just eyeballed it and built it.

I have a single float box controlling depth, set at 1 1/2". I have 3/4" pipe connecting the float box to flue pan and the flue pan to syrup pan.
As soon as I get boiling, the depth will drop to 1" and even lower sometimes as the float box struggles to keep up with the evaporation. The 3/4" pipe is not large enough. I have the arch tilted to be 1/4" lower at the front (syrup) than back to help the flow and keep more depth in the syrup pan.

[Zamkev]

That's very useful info - especially re the 3/4 feeder.

Given that I'm probably going to have a pan set made, do you think a second hot float box be useful - or not really needed if the pipe was larger?

thx.