flue temperature

[newbie2maple]

Last year we bought an older 2 x 6 grimm lightning evaporator. We had decent sap last year, around 2 for sugar content, but all we could make was dark syrup. Yesterday we made a trial run to see if we could figure out what we were doing wrong. Bought a stack thermometer and found out that we are only getting to a little over 300 degrees, which seems low based on what I've read in other post. Tried installing a damper but doesn't seem to be helping. Any ideas on what i can try to get temperature up.

[wiam]

I don't see how a damper would raise stack temp. It would make less draft=less fire. Is it a probe thermometer? A surface mount will read much lower than a probe. My surface read about 900 and my probe runs about 1300. Do you have a blower? Is the wood very dry?

[newbie2maple]

we have a natural fire arch. The probe is just a surface mount. The reason i put the damper on was because we had problems with the front finishing pan not getting hot enough. The wood is seasoned almost a year.

[BoarsNest]

Is your wood split about wrist size? Are you feeding the fire regularly... Every 5-7 minutes. Last year we ended setting a timer so we stayed on it. Someone on here said to feed it like a freight train.

[shane hickey]

Is your wood split about wrist size? Are you feeding the fire regularly... Every 5-7 minutes. Last year we ended setting a timer so we stayed on it. Someone on here said to feed it like a freight train.g


I would put wood in mine every 3 minutes but never fill it up.
Open one door put wood in open the other put wood in. We burnef
150 full cord a year. We could find enough wood nor had the
Time so i burn ng now. Old barns and pallets burn the best

[lakeview maple]

I Have a lightning arch and pans,2x6 2x3 flue pan and 2x3 syrup pan,and I have had it hot enough to melt the galvanization off the stack,you need to install AUF and it will boil like crazy.The reason your making only dark is its taking too long to reach your boil temp ,add the air and you will see a huge difference,Al

[newbie2maple]

Thanks for all the info everyone. Wood is split to about wrist size and feeding at the rate suggested, it seems like our biggest issue is not getting enough air to the fire. Gonna try and come up with a low budget solution.

[Spanielslovesappin]

Blowers are nice, but if you have 15+ feet of stack and also keep the draft door wide open and it should boil like gang busters. again, stoke only one side at a time with fine split wood. and do it every few min. one side, then a few min later the other side. run syrup pan depth ~ 2" no more. make sure you reach up through the draft door with a poker and scrape out any nails or cold coals plugging your grates. If it dosent look like your looking into hell (if you can look at it without roasting your face off) your not stoking hard enough. Boiled the same evap for a long time they work great! a blower wont fix questionable wood or improper stoking. Also dampers are not the answer!

[Maplebrook]

Newbie2maple,
Is your evaporator inside a building? The first year I boiled with my new evaporator it was in a 3-sided shack with the fire door to the open side. I couldn't get a boil in the front pan with the cold draft from outside on the front of the evaporator. An old-timer looked at it and told me to close in the open side...problem solved. Of course, the only way to close in said side was with an addition!:rolleyes:
Darren

[newbie2maple]

The building is enclosed but small. Only about 10 x 10

[BoarsNest]

If you have electricity for the blower that is probably a great solution. I had to put a 12 volt bilge blower on mine but it made a major difference.

[newbie2maple]

Thanks for all the info everyone. Gonna try again next weekend and hopefully get the problem
worked out before the season starts

[nymapleguy607]

Sounds like you need a hotter fire, make sure your wood is bone dry and you keep the draft door wide open, also cris-cross your wood when you fire this will give you more air flow. I would take out the damper, and make sure you have at least 12ft of stack, If it is 8in pipe then go taller, I think mine is 20ft with 8in stack. Make sure the area under the flue pan is right up to the bottom of the flue pan. You want it to ramp down about 4" from the stack collar, (This should help some with the syrup pan boiling to)
Remember with a natural draft arch you need enough draft to pull the flames back under the flue pan, the hot gases do little to make the flue pan boil. Make sure you have an underside flue brush and clean your flues each time before you boil, if a layer of soot is on the pans that will insulate the pan and won't give very good heat transfer. Give this a try before rigging up a blower it might save you some time, a blower is nice though :)