7' versus 6' flue pan for 3x10 cross flow?

[ryan marquette]

I am getting a new set of smokey lake pans next year. I'm going with 3x10 cross flow with a 7' flue pan. My question for the pros is what are the reasons someone would go with a 6' flue pan? Is it to make the evaps cheaper or is there another benefit I am not seeing? I just don't want to go with a 7' and learn the reason when its too late.
Thanks Ryan

[Sugarmaker]

Generally the longer the flue pan the faster the rig will boil sap. That's where the hard boiling evaporation is done. More surface area in the flue pan, more GPH boiled. So in general a 7 foot flue pan would be better than a 6 foot. I run a old antique King arch and pans, they are 5 foot flue and 5 foot syrup pan. Not as efficient. But still gets the job done:)
Regards,
Chris

[lpakiz]

I can chime in here. I have a 2 X 10 that has 8 feet of drop flues and 2 feet of syrup pan. Works great, and I highly recommend this ratio. If you think some day you will boil concentrate from an RO, the recommendation is OFF. Atho several people, more experienced than me, have assured me I would be OK boiling concentrate, it seems to me that you might be too near to syrup before liquid leaves the flue pan, potentially causing a foam-up in the flue pan. BTW, the 2 X 10 gets between 90 and 100 GPH.

[ryan marquette]

Thanks guys, Ipakiz thats what I am wondering with an ro & 7' flue can there be issues in the syrup pan.

[madmapler]

Another possibility is with the longer flue pan(drop flue) there is a tendancy to damage the end of the flue pan by slamming wood into it. This was the case with the one I bought(2.5x10). In speaking with a guy at Bascoms, he said it was common thing so some manufacturers started to build them shorter. I switched to a raised flue

[lpakiz]

That is an issue, for sure. Ryan Marquette, are you thinking drop flue or raised? With a raised, the wood damage problem disappears. That said, we use pretty small wood, and there is no "throwing" of wood into mine. Welders gloves and wood is placed in the arch, sometimes contacting the drop flues, but never "hitting" them. We cut wood to 20 inches, but occasionally it ends up longer. We pre-stage our wood on a 3-compartment rack and if we notice longer pieces, they get put into the arch in the first double handful, well under the drop flues. The grates are 39 inches long, so plenty of room for the first bundle of wood.

[ryan marquette]

Sorry guys I should have mentioned I have raised flue. Sean thats a good point & it would make sense that the big oem pan builders would make 6' the standard for raised & drop flues rather than making the raised 7' & drops 6'.

[Sugarmaker]

Give Jim a call and confirm the 3x7 raised flue. You should be real happy with that! Tell him I said hi:)
Regards,
Chris

[Bruce L]

I would go with a raised flue, 8' if not too much difference in price, you will see a big difference in evaporation rate, cutting down on boiling time and wood usage.