Calm winds = poor boil?

[bison1973]

My evap is really frustrating me this year. I added a blower and it seems to be getting less GPH this year (80-85) than last year with natural draft (90-100). But at least the first week it was acceptable.

Now for the lat two days the GPH rate is terrible (50-60). We've have had no wind to speak of. Could this be hurting things even though I still have a blower running? It's like nothing wants to go up the stack (ash coming out the doors terribly bad). I added a stack therm and I'm getting temps of 300-500 (I don't know what the temps were the first week when it was going better because I didn't have the thermometer then). I know these temps aren't good at all.

What's the recommend space under the back of the flue pan to exit into the stack? I thought for a blower I heard it should be closed up more than natural draft.

Or is it just the lack of wind leading to a poor draw creating all these problems?

[3rdgen.maple]

What size stack is on it? And how high? This season has been a killer for boiling at my place. Never seen the such sparatic boiling. One minute its boiling like I never could even imagine and then bam a lazy boil. Seems like every 10 hours of boiling I have gotten 2 decent hours out of it. Fustrating made no changes to the evaporator at all proir to all this. It is the atmospheric pressure that is causing this for me anyways and I am betting a little of yours as well.

[Flat Lander Sugaring]

I beleive it's the barometric pressure and humidity that seem to determine the boil.

3-31-11 2% sap
Like last night here some stats.
Seemed to be boiling really good a lot of steam
6:15 PM
Temp. 43 deg F
Baro: 29.77 Falling
Humidity: 53%
Dew Point: 27 deg F
Stack temp: just over 1000
Sap entering float: 140 to 160
4 Labatts:cry:

Hardly any steam
9:00 PM
Temp: 39 deg F
Baro: 29.77 Rising
Humidity: 56%
Dew Point: 25 deg F
Stack temp: 1200+
Sap entering float: 180+
2Qt maybe 2.5 Syrup
6 Labatts:lol:

When I noticed steam letting up I started pouring the hardwood to it. Thats why the stack temp and sap temp went up considerably but less steam.

When I shut down at 10:30 if I remember Humidity was towards 60% I just didn't write it down. Real lazy last night with stats just getting burned out.


Here's another night 90 gal sap @ 2.8%
3-24-11
7:45 PM
Temp: 28 deg F
Baro: 29.79 Steady
Humidity: 52%
Dew Point: 16 deg F
Steam was so heavy I had to open doors, you couldn't see across room to other side.
Very Heavy Steam
6 Labatts:lol:

I think for next year I am going to have some one make me up a spread sheet with everything on it including syrup draw, steam amount, stack temp, sap temp and everything else you see above plus any more if think of it.

[bison1973]

It's a 3x10 raised flue. 14" stack I think 13-14 ft in height.

[PerryW]

I always figured no wind would be better for boiling. I seem to get about 90-100 GPH with my 3x10 w/ no blower. My take on a blower is it helps only if you have poor wood.

[PerryW]

I have 20 feet of 15" stack on my 3x10. I always figured no wind would be better for boiling. I seem to get about 90-100 GPH with my 3x10 w/ no blower.

[MilesTeg]

Just a thought I'm not too experienced but is your blower under sized? I put a brick on the ash door to help the ashes from not blowing out.

[Farmboy]

My 2.5X8 has a 14" stack. That might be a little undersized for a 3X10

[bison1973]

Found out what the problem was. I had a buch of arch board type isulation blocking up the area right before the smokestack. I had used it to insulate the inside of the front of the arch. A bunch of it came loose and made it to the back. Things seem back to normal now.