Flue pan/flat pan size ratio

[Tomhop]

Hi, I have recently had a flue pan made(30 by 48) and it boils pretty well. I think I made a major blunder, however, when I installed two 12 by 30 crossflow flat pans for syrup pans. The flat pans don't seem to keep up with the output from the flue pan. Is there a formula for figuring the correct size for the flat pans? I am going to have a new flat pan made, and I want to make sure this one is the correct size.
Thanks, Tom Hopkins

[powerdub]

I am not sure what you mean by the flat pans don't seem to keep up with the output from the flue pan. Could you give us a little more info? Maybe an example. Does the back pan make syrup?

[syrupmaker]

Tomhop....Might not have to make a new set of pans yet.How are you flowing the sap between the two pans?Float box or tube, flue pan to front pan? :? If you have any pictures of it could you post them on here so we can look and get a better idea of what you have.If you are not able to post them here can you send them to me at SYRUPMAKR@AOL.COM

I'll take a look and see what can be suggested from there.

Rick

[Tomhop]

Hi Guys,
Thanks for the replies. My 30in by 48in flue pan boils so fast that the two 12in by 30in pans cannot handle the output. The flue pan is in the front, followed by a 12 by 30 crossflow flat pan, then another 12 by 30 crossflow. All three pans are connected by freeflowing pipe connections. The flow is in one direction only(at this time) from pan 1 to pan 2 to pan 3 to outlet. I had hoped to draw off from pan 3 after the sap was 'on the float'. I wanted the sap to be almost syrup at draw off to save time in my propane fired finish pan.
The problem is the two flat pans don't boil fast enough to get the sap to the float stage (in the flat pans) before the sap in the flue pan has gotten dark. I suspect that my flat pans aren't large enough, and that my crossflow setup is the wrong way to go. Are my suspicions correct, or have I been drinking too much sassafrass tea? Thanks, Tom

[syrupmaker]

Tom...The manufactured rigs have a means of controling sap level in the pans ,usually by a float set up. Sounds like you are useing the same pans as us,What we have is a valve between the flue and sap pan and run the sap pan 4-5" deep. The syrup pans run around 3/4" and we regulate the valve to keep a constant levle on the thermometer.When it's time to draw we crack the valve a bit more and the flue pan levle pushes the syrup pan to the draw off. Once you start your draw the valve can be left cracked ,keep the fire to it and let the pans work for you. Send me your e-mail address and i'll send you pictures of ours.

Rick

[powerdub]

You want the back pan to do most of the boiling for you. If you were looking to get your first draw with all fresh sap out of the front pans in 30 minutes it aint going to happen. I would be patient, and try some of the things suggested here. The sap will darken some in the back pan no matter what size it is. Hang in there and give it a little time. No two evaps run the same no matter how close to the same they are.