Copper Tubing Preheater

[scw]

Just wondering if anyone has had any experience using copper tubing wrapped around the stove pipe as a pre-heater. I used 50’ of ½” copper around 8” pipe, and in a test boil, it hardly warmed the water that was coming through. I am going to add another 20’ of copper to see if that will do it. Maybe I did not give the system enough time to heat up. Any suggestions?

[nmerritt]

Watch that the sap doesn't start to change inside the copper pipe. If you aren't drawing off quick enough, that could cause some problems.

[VA maple guy]

Hi SCW, If you look under homeade maple equipment and click on (preheater) Johnny Cuervo posted some pictures of his copper tubing
preheater. He states his sap comes out at about 140 F.
I plan on building one this year similar to his.
If your letting the sap flow through the 1/2 pipe unrestricted,
it won't have enough time to get hot. Try putting a ball valve
on the pipe and play with how far you have the valve open.
Just don't close it so much that the sap boiles in the pipe.
You may also think about attatching the pipe to the stack
a different way. You can't change how much pipe is contacting
the stack when you wrap it arround it. You may need to
change the amount of contact while in the middel of a boil.
Gerry

[ontario guy]

Hi,

My neighbour and i have both done this... his is 1/2 inch and mine is 3/8. He half inch is harder to bend and keep a tight radius on the pipe. ( and it kinks very easily. i would recommend putting a valve on the bottom. so you keep your pipe full and have just a trickle going into the pan. If you start fresh try bending it around a 7 inch pipe then unscrew it from the 7 and screw/thread it onto the 8 inch. This will make a nice tight fit and should work better. (we found this out by trial and error.)

We both have nice warm sap, and mine boils in the pipe on occasion.

Mark

[WESTVIRGINIAMAPLER]

One year I ran a piece of 1/2" copper tubing thru the entire 7' length of my firebox and had a coupling about 2 feet above the rear of the pan. This way the sap was boiling and when it came into the pan and when I wasn't feeding the pan, I unhooked the coupling and poured aproximately a quart of water thru it to flush out any left over sap so it would scorch. This was the last year I had my backyard setup! :D

[scw]

Well, I tried 3/8 and unrestricted, it only flowed 20 gallons/hour and the 2x6 should boil 25 gal/hour. Math does not add up quite right. I had an elbow in there and was using Tygon to make the connections though. I have already abandoned that and gone to 1/2" with compression fittings and no Tygon. It was hard to wrap it around the pipe tight and it does have limited contact with the pipe itself. I did a test boil with water, and, unrestricted, it rocketed through (at 60 gal/hour) and did not heat up at all. I have since added another 20' of tubing, and wrapped the tubing and stack with some fiberglass insulation with a reflective pipe wrap over that. Next year I will try to wrap it around the 7" pipe before. Ball valve at the float is going in tonight. Thanks for the advice. We will see what happens, if winter ever comes and goes. I should have tapped 3 weeks ago here. . .

[RUSTYBUCKET]

We've never tried this but a friend experimented with a coil of copper around his stack. Initially, the syrup got so hot he said it was exiting the tubing as little pellets. :(