What's going on??

[jstaples]

I recently purchased a 2x4 evaporator that is rated at 9-12gph...with me doing the math i'm only getting 5.5gph. My raw sap is about 47 degrees when it's coming out of my warmer into the pan. The arch is bricked all around with a double stack to push the flame up to the pan. I'm burning dry 2x4's but just can't seem to get about 5.5gph. Any help would be great.

[backyard sugaring]

The theory is 1 gallon for every sq. ft. on a flat pan. good luck,Lee

[jstaples]

I forgot to mention that the pan is a sectional pan for syrup density.

[Maplehobbyist]

It's probably the 47 degree sap going in that's the culprit. That's cold enough to kill the boil in part of your pan, so you're effective area is less than your actual area. If you don't have sap going in the the pan, do you get a boil everywhere?

[Schiefe4]

Is the arch insulated with arch board or ceramic blanket? (Between the arch and firebrick) Have you considered using a pre-heater?(I have personally found a pre-heater to raise sap temperatures to the upper 180F before sap enters the divided pan) What is the liquid level in your pan and is it a consistent level? (Maybe try 1"-1.5")

[jstaples]

If I don't have sap coming out of my preheater into my pan I do have a pretty good boil all over entire pan but mostly up over the fire box. The arch is not insulated, just bricked. I have been running the liquid about 2" to 2.5".

[Starting Small]

I get about 10GPH with a 2X3. I have arch paper but the big difference maker is the blower. When I turn the blower off to feed wood, it takes seconds for the boil rate and steam level to drop like a rock in between turning the blower off and opening the door. So I know it is the blower and not the door opening. I also pack as much wood into the evaporator as I can fit. I go through alot of wood and lose heat out the stack but I burn alot quicker and for me speed is more important than wood consumption. My wood is free. I also take the preheating/warmer and slide it back an inch or two. When I did that it warms the sap quite high where it is almost too hot to touch as it gets down to 1/4 full. Of course with the blower my stack is glowing orange. For 150 bucks I would get a blower from Bill Mason. Good luck,
-Dave

[Ren]

Try running it at 1". Just have a stand by pail of sap on the ready. I think your problems is the 2 to 2.5" depth of sap.

[Dill]

Are you inside a building?
And is there a breeze hitting your pan?

[bowtie]

not having archboard should not make a big deal, try running sap at most 1 1/2 " . do you have a blower? if not you will have to "fire" at just the right time to as not kill the boil. my 2x4 with blower and dry pallet wood will boil at 15-17 gph but i go through a lot of wood and i keep the stack glowing red! my pre-heater maybe gets my sap up to luke warm to warm so i do not gain a bunch but every bit helps. if you run shallower you should get the 9-12 gph, if you can add a blower this helps a ton. if you experiement with it you should get you boil up better. if you can add some hardwood in you will get more btu's and will not fire it as much, like i said when you fire the arch it will slow your boil down some, especially with a smaller arch.

[jstaples]

Thanks for all the help. The only thing that i see about running around an inch in the pan is that my pan thermometer is at about 1.5 inches....not sure if I'll get a good reading with that low level of sap...but that' minor i guess. I think I will try and burn some hardwood and try and find some type of blower that's not going to rake me....thanks again.

[Lazarus]

If your thermometer is that height, you might consider getting one with a longer stalk. Check out Bascom Maple's website. They have all different lengths.
I had this problem when I went from a 2x3 Mason with a short stalk to my GBM 2x6. I was told I could use my same thermometer but then I had to run pans at 2". Made a lot of coal tar before I figured out a much longer stalk on a new thermometer got me a lot closer to the pan bottom.