parralel flow preheater questions

[markct]

i want to make up a copper preheater to go in my steam hood for this season, i already have the drip pan in there and all just gota make the copper part itself. i plan to simply do it with 3/4 tees on each end and half inch copper running the lenthwise runs, now i have heard different stuff about pitching it up towards the outlet end i think it was? or was it the inlet higher? and what about venting it? needed or does the proper pitch make that unneccesary?

[WESTVIRGINIAMAPLER]

Mark,

I didn't vent mine and have about 3 to 4 inches of rise from low end where sap comes in to high end where it goes out. I have some pics in my weblink below that might help you some. Better stick with 3/4" instead of 1/2" at least feeding the evaporator. Go with the thin walled copper pipe too and Fred and some of the others have used the copper pipe with fins on it and it appears to work a lot better but I have never tried it. I usually run 170 to 175 degrees with damper open.

[NH Maplemaker]

I modeled mine after Brandons and I did haft to vent it as it kept locking up. I used 1" thin walled copper.
I also have a 3" to 4" rise at feed end ! If you add a vent make sure the top of it is higher than your head tank ! Jim L.

[WESTVIRGINIAMAPLER]

I run my evaporator about 1.5 to 2 inches deep and maybe it has something to do with the Leader float boxes because even when my vapor locks a little, when the level drops down a touch in the evaporator, it purges itself of all the steam and vapor and takes right off. Be interested to know if maybe it has something to do with the design of the float boxes by different manufactures that are more suseptible to vapor lock vs others.

[KenWP]

Just for curiosity what is this finned copper pipe actually called.

[Gary R]

Stick with the 3/4" Type "M" is thin wall. Outlet needs to be higher than inlet or the cold sap would run right through. I do not have a float. My vent is only about 1" above the preheater. If you have floats, you'll need to vent above your head tank as mentioned.

[cncaboose]

I believe it is just called fin tubing. I used 4' sections of it that I ordered from a plumbing supply store. Not very expensive since it is what is used in baseboard hot water heat installations and isn't really a specialty item.

[Fred Henderson]

Stick with the 3/4" Type "M" is thin wall. Outlet needs to be higher than inlet or the cold sap would run right through. I do not have a float. My vent is only about 1" above the preheater. If you have floats, you'll need to vent above your head tank as mentioned.

"M" is thin but not the thinest. The tubing used in baseboard radiation is thinner.

[Fred Henderson]

I believe it is just called fin tubing. I used 4' sections of it that I ordered from a plumbing supply store. Not very expensive since it is what is used in baseboard hot water heat installations and isn't really a specialty item.

If yoy can buy wholesale from a plumbibg suppy house you can get it in 10 foot lenghts.