Pre heater Questions

[Jerome]

I will adding a pre-heater to my 2X4 this season. it will be 8 inches wide and 48 long, I was hopping to install it 4 inches from the far side giving me 12 inches of access on the accessible side to clear foam etc. Will this work or does it need to be centered?
Also if I was to feed it from one side would the sap be evenly distributed or would one run do most of the work?
Thanks

[NYScott]

First I am in no means an expert. But I do try and do my research. From what I understand and this actually surprised me when I heard it, your preheater should be plumbed in parallel and the sap should be forced to run uphill. I guess the ones made by leader use 1-1/4" copper headers on both ends and 3/4" copper runs down the length. This will be my first season tapping and boiling. The evaporator I purchased had a steam hood and preheater on it. I think the steam hood was made by leader. The preheater is homemade. You will need a damper in the pipe letting steam out of the hood. You will need a drip pan under the preheater. On my rig in 6ft. the preheater runs uphill 1", I also put a vent in this just in case I build up pressure in the preheater and create a vapor lock situation that would starve the back pan.
Happy tapping

[smitty76]

First I am in no means an expert. But I do try and do my research. From what I understand and this actually surprised me when I heard it, your preheater should be plumbed in parallel and the sap should be forced to run uphill. I guess the ones made by leader use 1-1/4" copper headers on both ends and 3/4" copper runs down the length. This will be my first season tapping and boiling. The evaporator I purchased had a steam hood and preheater on it. I think the steam hood was made by leader. The preheater is homemade. You will need a damper in the pipe letting steam out of the hood. You will need a drip pan under the preheater. On my rig in 6ft. the preheater runs uphill 1", I also put a vent in this just in case I build up pressure in the preheater and create a vapor lock situation that would starve the back pan.
Happy tapping
I am no expert either, but I can not understand why the sap runs up hill in the prehearter. Our preheater and hoods are home made as well. The preheater does not run up but we do have it vented to prevent air/vapor lock and we also have a drip pan under it. It also has a thermameter and preheated sap temps run about 140 degs. We would like to add to it and get the sap temp up as much as we can.

[NYScott]

I really can't tell you why on this one. I'm taking this as gospel from "Leader Evaporator" and a local distributor. My preheater was plumbed uphill and after I made some mods to it both entities said straight up "make sure the sap runs up hill through it" I was lucky and had not altered that particular aspect, I'm going to be working on finishing up my steam stack today. I might be able to take some pics if you'de like. Or heck call "Leader" over in VT. and ask them yourself.

[smitty76]

Yes, I would be interesrted in pics, take all you can.

[Big_Eddy]

My understanding.

If it runs uphill and boils - steam will rise towards the outlet and exit
the preheater at the valve. As the flue pan level does not change, the valve will remain open until all the steam has escaped and more sap flows in from behind.

It if is running downhill and it boils, the steam will rise back into the piping, creating a vapour lock and no matter how long the valve calls for sap, any sap that gets by the lock will boil off in the hot empty tubes before it gets to the flue pan.

The runs are in parallel because if they were in series, then the sap would have to flow downhill on the second run - causing the same issue to occur.

[Haynes Forest Products]

Big Eddy: You have put it into words that I understand............My dang ADD, ADHD, HD, HDTV was keeping me from the total concept of the parellel and slight slope. Now I need one more thing from you. Can you get along with a single drip tray on the bottom pipe? Im thinking the drips will run down the pipes or does it form to fast and drop to early.

[Sugarmaker]

We use a concept called drip channels, 1 under each pipe and it works well and does not restrict steam heat flow to the pipes. It does drip off all along the sloped tubs. We get about 7 gal per hour off the drip channels.

Chris