New idea for pre heater, opinions?

[rookie]

I want your opinions
I am making a new evaporator and my idea for a preheater is as follows:


the evap is a vertical 275 oil tank, a copper pipe (1/2 0r 3/4) will enter the top of the back where the stack comes out, it will make a couple zig zags then enter out the front of my stack area above the pan on a valve so i can regulate the flow,
my questions are these,

1.will the solder on the 90's melt cause of the heat?
2. does any one under stand what im talking about?

the idea behind this is to not have a condensation drip back into the pan.

[Ecnerwal]

Understand what you're talking about pretty well, but don't think it's a good idea.

So long as there's liquid sap in the tube, the solder won't melt.

But - you stand good chance of boiling the sap in the preheat tube this way - and then the solder can melt, the sap won't flow, etc....

Also, if at any point you stop feeding sap in (run out or can't boil fast enough, etc) the solder will melt.

(Steam) Preheat condensation should be caught and directed outside the pan (many save it as a handy source of clean hot distilled water for cleaning things.) Pre-heating with steam has the advantage of not overheating the preheater when sap flow is slow or stopped.

If you want to preheat something in your flue, preheat the air from your blower (blower first, then preheat, then feed to fire - don't preheat it before the blower or the blower will be unhappy.)

Some folks do use a coil of soft copper outside the flue for sap preheat - no joints to melt and not quite as hot.

[Jec]

Yeah I agree the steam comming out of the pan is 212F. So if a preheater is there with no sap it won't melt. Also the steam will preheat it from 160F to 180F. That is a good temp to not have the sap evaporate too much and it won't kill the boil. You can always put a drip tray under the preheater so any condensation will drip into that then run into your drip edge in your hood. The stack is too hot for sap.