not happy with test boil today

[sweetmoomoo]

did a test boil today with my arch in my new shack and the blower hooked up, with the blower on i would not get a full boil on my 2x3 flat pan only the front would boil i was really thinking i was going to get a great rolling boil across the whole pan. tried with the blower on diffrent settings also. i have the blower coming in from the back of the fire box and blowing under the grate. turned the blower off and got a real nice boil on the whole pan with the ash door open. got about 8gph once i was up and running on natraul draft. anyone ever have a problem like this with there blower? also found out my coupala is to small.
http://i942.photobucket.com/albums/ad269/hpmud/0301151308.jpg (http://s942.photobucket.com/user/hpmud/media/0301151308.jpg.html)

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[Sugarmaker]

Sounds like you may have too much air going in the bottom. A damper may help? Did you try the AUF after you had a good boil?
Regards,
Chris

[Ausable]

I just use natural draft on my home made arch. But - I operated boilers - years ago. Sounds like you are messing up the draft flow - from fire box to stack - with where You have the blower located. Air from the front - under the grates - about where Your ash door is located - would work better. I'm sure some of the other guys and gals - that use forced draft - will chime in.

[asknupp]

I made an airtight arch this year and have boiled a couple times already. The arch is auf/aof but I only run the auf probably 20% open and aof 70%. Sounds to me like your pushing all your heat up the stack.

[CampHamp]

Did the wood burn much faster? Did the smoke coming out of the stack look different?

My smoke goes from black to clear when I use the blower and I need to feed it twice as often.

Can you make it even blow even lower by blocking the inlet to see how she burns? Is the air blowing towards the door or straight up the grates?

[sweetmoomoo]

i have the blower on a variable speed controller and from lowest to highest no good, i did notice that the front of the arch got very hot and there was some air blowing out around the door and ash door. im going to try blowing in from the front of the fire box to see if that makes a difference .i could here the fire roaring and it was eating more wood but no boil. im going to keep tinkering with it, thats half of the fun.

[CampHamp]

I like fiddling with this kind of stuff too... It would be nice to have the blower tucked underneath. If it's blowing forward now, maybe you could cap it and drill holes shooting upwards?

[5050racing]

My blower enters from middle of the bottom 12" back from door but. Have 8" flue pipe with a damper 30" up what size pipe u using? My blower enters thru a 2" hole spaced 2" above the hole is a 8" disc of 1/4" steel plate to diffuse air like a burner on a stove look I boil 2 pans that r 2'by2' n they boil hard blower has 3 speeds most time on med

[Sugarmaker]

i have the blower on a variable speed controller and from lowest to highest no good, i did notice that the front of the arch got very hot and there was some air blowing out around the door and ash door. im going to try blowing in from the front of the fire box to see if that makes a difference .i could here the fire roaring and it was eating more wood but no boil. im going to keep tinkering with it, thats half of the fun.
Hi,
Not sure how big your blower is? But if you have air coming out the front and the door when on the lowest speed then you probably have too much air. For a rig this size you might not need much more than a big hair drier? do you have a damper on the inlet?
The other thing is that if it boils like crazy with natural draft I would use it that way. All rigs are different. One thing that may be a slight diss advantage is that large area for heat in back of your boiling pan that is half as big as the fire box and lots of heat may be in that area and not under your pans?
Regards,
Chris

[CampHamp]

I think I can picture what you're describing. Somehow, even with more burning in the firebox, you have cooler air hitting the back of your pan with the blower on. The blower is either introducing too much cold air or it's making the heat pass further underneath the back of the pan. Make sure there is only a small gap under that back pan and the arch floor, get your fire as big as you can with thin dry wood, then see if adding air is helping or not... I agree with SugarMaker, it could be that you have a strong natural draft in you system already and may not need the blower. Let us know how you go!

[sweetmoomoo]

going to get started on some mods to my arch today, first of im am going to cut off the rear top section of the arch where the stove pipe comes out to reduce the amount of space that heat can be trapped in like sugar maker pointed out . i would like to cut it all off in order to fit a longer pan one day but dont know how i would pre heat my sap, so for now i am just cutting off the top rounded section. second on my to do list is to move the blower to the front and blow in threw the ash door. seemed like i was loosing to much heat out the front of the arch. think i have a few days before i get a good run of sap to get this thing dialed in.

[psparr]

Don't cut off the rounded part! That helps spread the fire out under the pan before going up the stack. If you just have the stack and not the rounded part, you'll funnel the heat to the center of the arch away from the edges of the pan. Make sure you only have about 1-1/2" of space under the pan after the ramp. That will force the heat up under the pan. Good luck.

[sweetmoomoo]

update on my mods to the arch, i cut off the back rounded top part of the oil tank ( saw that psparr advised me not to after i had allready cut into it) and raised the fire bricks closer to the pan by adding ceramic blanket under them, i now have about a 1 in. gap under the back of the pan. i also added a 2 in. pipe to the blower into the fire box and capped it off, cut slots with my angle grinder along the top of the pipe so the air is blowing stirght up under the fire.test boil today went real good ,almost all of the pan had a good rolling boil just one back corner was a little slow on the boil but i timed it out and did just about 10 gph running the blower and eating alot of wood. ready for next week.
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