Preheater around the stack

[Johnjenner]

Just bought a leader 2x6 wse and needing to add a preheater. Currently does not have a hood (may build one) and wondering if anyone has had success using copper pipe around the stack as a preheater. Good/bad???

[mol1jb]

Just bought a leader 2x6 wse and needing to add a preheater. Currently does not have a hood (may build one) and wondering if anyone has had success using copper pipe around the stack as a preheater. Good/bad???

I have heard of mixed results doing this. Since a stack can reach very hot temps you must be careful not to scourch the sap in the preheater tube. And you can also boil the sap in the tube which increases chances of vapor lock. To get the best and most consistent results build the traditional parallel flow preheater and hood.

[Haynes Forest Products]

As long as you keep the sap moving at a good speed you can get some heat transfer but there is a point like mentioned vapor lock right before a steam spewing stack rumbling power washer overwhelms your float valve backing up into the head tank belching sap all over the place. With a few safe guards you can over come it.

what I have learned is keep the sap moving have a way to flush the sap out with clear water as you shut down and the smaller the tube less forgiving it is.

[Super Sapper]

With a 2 x 6 I am not sure how much you will be able to heat the sap as it will be flowing at a pretty good rate. If you do try it I would suggest having the sap come in at the bottom of the spiral and out the top. This should help with any vapor lock.

[maple flats]

If you want to use the stack method, look at this: http://flickr.com/photos/57535094@N0...7601539320490/
It is by member Johnny Cuervo. He has a post telling how he made it. It is very effective at 17-18 gph, you may need more feet to do 25-30 gph if you want 160-170F sap. On the other hand 110-120F is still far better than 35F.

[Michael Greer]

Steam is a much better heat transfer medium without the risk of burning anything.

[Johnny Yooper]

Just bought a leader 2x6 wse and needing to add a preheater. Currently does not have a hood (may build one) and wondering if anyone has had success using copper pipe around the stack as a preheater. Good/bad???

I've been doing this for several years - copper tubing wrapped around the stack, 40F sap in, 160F sap out, haven't had issues with burning or vapor lock so far.

[wobbletop]

If you want to use the stack method, look at this: http://flickr.com/photos/57535094@N0...7601539320490/
It is by member Johnny Cuervo. He has a post telling how he made it. It is very effective at 17-18 gph, you may need more feet to do 25-30 gph if you want 160-170F sap. On the other hand 110-120F is still far better than 35F.

Link no workie... :)