Preheater size

[mapleack]

Hi, I'm starting on plans to build a parallel flow preheater for my 3'x7' flue pan. What I'm wondering is what would the ideal dimensions be for a preheater in a pan this size. I'm thinking 18" wide by 5' long with 10 3/4 copper tubes. Any suggestions or advice is appreciated! Thanks!
-Andy

[brookledge]

I have a 3X8 flue pan and I can count mine if you want along with the length
Keith

[Haynes Forest Products]

if your flue pan is 5 ft then I would make it as long and wide as possible and still fit inside the flue pan. I would start with figuring out what the condensate tray size will be and then how it will mount and will it be inside the hood or setting on the pan rails. I think what happens is people get to cutting and soldering pipe and making a nice big heater and then they fight like hell to fit trays under it and then get it to be user friendly when it comes to removing and cleaning the pans.

[Fred Henderson]

I got a 3x5 flue pan. My drip pan is mounted to the hood and the preheater sits in it. When I remove the hood for cleaning of the flue pan off comes the preheater.

[Gary R]

Andy,

Check with Sugarmaker, he made one for his 3X10 and gets 200 degrees. I think you will need to add as many tubes as possible wide. I just made one a couple weeks ago. I only got about 160. But my hood is not tight. Also probably need 1" upper and lower manifold.

Good Luck and let us know how it works!

[Sugarmaker]

Andy,
I had Leader help in designing and building mine. I used 1-1/4 inch cross manifolds and then silver soldered copper nipples to them in 10 places and ran about 4 feet of thin wall copper between them. Then silver soldered them in place. Cold sap in the low end with the high end, outlet raised about 4 inches. I have 3 vents at the top end that run a small constant stream back into the pan. Gary is right if I fire consistently I can get 200 deg. sap entering the float box.
I have a partial damper in the steam outlet pipe. My hood is not real tight.

Regards,
Chris