Raised or Drop Flue?

[YoungFamilyFarm]

So the plan is an AA Metal shop evaporator between a 2x10 and 30x12. Whatever size I decide on, I want to be efficient with wood and draw from the rear of the pan. So a four channel syrup pan, opposite side reversing. Now, I looked at a brand new Leader American drop flue 3x10 at a dealer today. I planned on a raised flue, but forgot how simple reversing is on those "old school" single float set-ups. Just plug em off/on and switch sides. As tempting as it was to just buy that one.... Well, never mind I can't afford it! What do you guys have to say about it? Why the modern push toward raised flue? Is it purely to run lower levels in the flue pan to increase rate? Is there a reason I shouldn't look at going the "traditional" drop flue route? I appreciate all input!

[Thompson's Tree Farm]

I never knew one was more traditional than the other, Both have been around for over 100 years. I grew up with a raised flue and prefer a raised flue. Someone that cut their teeth on a drop flue probably prefers that. Evaporation rates are about =. It is easier to put raised flue pans on and off the arch and there is less chance of hitting the flues with a chunk of wood. You can manage sap depth separately because of 2 floats.

[TRAILGUY]

my first was raised now droped, the raise was much easier to drain for cleaning flue pan

[rayi]

I have a drop flu. I think if I had it to do over I would go with a raised simply because you can control both pans at different levels

[Tweegs]

I have a drop flue.
I’ve heard it said that the flues are easier to clean between firings (fire side, not sap side). I wouldn’t know as this one is my first.

Still, I think I’d give up that…ahem…”luxury” for the chance to control levels in both pans independently.

[maple flats]

My 2x6 was a drop flue, then my 3x8 came as a raised flue, and later on I had new pans made with 10" tall flues and that is also raised flue. Having used both, I definitely like raised better. I run my flues pan at 1/4-1/2" over the flues and run the syrup pan at 1" deep. My wife runs the flues pan at 3/4" over the flues and 1.5" in the syrup pan. I get slightly more production per hr, but not by a huge margin. Running 10% concentrate I get 8-8.5 gph of syrup and she gets 7.5-8.0. We both run fueling every 9 minutes and both run the AUF/AOF full time, from start to finish. We could push is even faster but like the speed we now get, it is less stressful and lowering the depth and firing every 8 minutes. However, when we do that we get about 1/2 more syrup/hr. That's the hardest I ever pushed it, some out there might choose to push even harder.

[VT_K9]

About 7 years ago we went from a raise flue 2x6 to a drop flue 2x6. Draining the sap from a raised flue is easier. The drop flue is easier to clean the under side. I don't feel as though the drop flue has the evaporation rate as our raised flue.

Mike