hood to steam hood conversion

[Kev]

Hi everyone
As you can see I am pretty new here. not quite as new to sugaring but pretty green at that too. I helped my dad with this hobby/ obbsesion for several years before he called it quits due to health reasons and warm sunny florida in the calling him in the winter.
here are my questions- I am planing to add a preheater in the hood. are more tubes of a smaller size more effective than less large tubes?
my homemade flue heater works great in conjunction with the preheater Dad had made for the back half of the pan. Output from the combined heaters averages 170 degrees, how high is too high? or is there such a thing?
the flue part I can only use when i have a large amount of sap to run thru as I have to keep a large amount of head pressure to keep flow consistant.
once I am down to about 25 gal. of sap I have to shut down, close valves, undo unions drain down flue heater. Then connect supply hose union to union on dads preheater to continue flow into the pan. Then the flush the flue heater with water. If i do not you can imagine the mess involved.
I did this the last year dad was around but no longer "in charge" and he would just comeout to the shack to spell me once in a while. LOL he was impressed with the output temp. but not so impressed with the frantic activity during the transition period. especially sense when he was watching i managed to run spill a bunch of sap all over the back of the arch and pan.:emb:

[Haynes Forest Products]

One big pipe wont allow for enough heat transfer as the sap runs thru the heater. One small pipe will get hotter quicker but will be traveling to fast for good transfer. Think of your pipe as a train track and the water is the train that heat rides on. So if the train is moving to fast heat cant get on so smaller tubes more train tracks. Bigger train more heat can get on but it needs to slow down. I say your better off with smaller tubes and more of them. You can come in with 3/4 and then take it down to 1/2 or smaller. As long as your nor making steam in the preheater your ok. Now the hotter it is the more chance of vapor locking so get to the preheater site and see how people are doing it. You do want a vent pipe as part of the all over design.

[Kev]

Thank you! i guess I had not found the preheater site:emb:
I was sure I needed a balance of volume and flow rate and surface area for max effectiveness. Hence the question lol. With the price of copper today I saw no point in completely reinventinting the wheel with several attempts at trail and error.

[Haynes Forest Products]

Kev what makes you so special and differant that you cant spend a few years throwing money down a s&*(^&% hole:) The slower it moves the better as long as the piping will supply enough liquid. Its the fittings so get them from a good supply house that offers alot of configerations so you cut down on fittings and size. Check the copper wall thickness you dont need heavy thick wall.