Bought my 1st evaporator Friday & have questions about where to add blower fan.

[claystroup]

I am a newbie to maple sugaring and bought a used evaporator Friday night. The guy I bought it from made 12 identical units last winter and I bought the one he used and kept for himself. It has a 36" long x 18" wide x 14" tall burn area under the pan but has a nice 6" tapering to about 4" extension off the back for the chimney to sit on one side and a warming pot on the other side. This extension is 16" in length behind the pan. The pan itself is 20" x 38" x 5" flat open stainless pan with a drain valve on one end. Not quite as nice of a setup as the factory made units but alot better than I could have made myself and the price was right. I would like to add a blower for combustion air to help the boil rate and am looking for suggestions as to the best place to install it. There is no ash tray trough to duct it into, just a flat bottom. It would be easy to add in the back under the 16" tapered extension but harder to add in the front as the door opens all the way to the bottom of unit. Any recommendations would be appreciated. I have 35 sugar maples on my property that I can tap but plan on starting with 12-15 next year so I can learn the system. If all goes well in a couple years and I tap all the trees I would probably upgrade to a Mason 2 x 4 set up. Thanks, Clay

[madmapler]

A few pictures would be helpful but going by your description, having no place under the fire for ashes to drop is a real drawback in that your fire box will steadily shrink during a boil and there's no place to get air underneath it even for natural ventilation let alone forced air. Even if you were to fabricate some sort of grate and set it up on some bricks it would be better although 14.5 " isn't a lot of extra room to play with. At least you could clean it out through the front door which you say goes to the bottom. Most if not all evaporators get their forced air from the back of the firebox so you would want it to come in under the grate in the back. You didn't mention whether the firebox was insulated or not but if it's not then you'll definitely need to do it especially on and around the front door.

[maple flats]

At only 5" tall on the pan, you may not be able to force the fire too much. My syrup pan is 14" tall and has 8" high dividers. When I get the boil going real good, I still get very minor jumping of the sap over the dividers. This is very minimal, but it happens even on 8" dividers. With 5" you might get too much jumping out if the fire really roars. If you try forced draft, be sure to design a damper on the blower inlet to regulate the burn.

[claystroup]

I took some quick measurements last night and I am pretty sure I can make a 8" wide by 5" deep by 30" long fire box and mount underneath what I have and then plasma cut grates into the floor of the present unit. I could then mount a smaller blower ( I have a 110 cfm bath fan out in the shop ) with a 3" round outlet that I could pipe into a 3" round opening/sleeve that I could weld onto the back of the ash pan. Thanks, Clay