Custom forced air questions

[sugaringcrazy]

I'm trying to introduce forced air into my arch and here are my questions. I have a homemade arch that used to be a oil burning rig and it has a hole in the door that is covered with a steel plate, but I could easily take it off and attach some sort of piping from a blower outside the sugarhouse. (noise reduction) Or my other thought is to cut a hole in the back of the arch beneath the grates, then just blow air in, or come up with some sort of manifold that distributes air through several nipples right up into the coals. To me, I think the latter solution is the best, but using the hole in the door is certainly the easiest. I do know that AOF is efficient, but I don't think forced air just coming through the door is going to do the trick. Any thoughts are certainly appreciated. I will also note that I'm worried about creating a manifold and using nipples that shoot up through the grates as I think they will melt....

[psparr]

Under the grate is best. Any air will do better than no air. I just run a restricted leaf blower into the ash door and get a great boil.

[RileySugarbush]

Best first step in forced air is a blower into the area under the grate. You won't need much to see a huge improvement. No need for nozzles, I had great results with an opening in the back of the ash area, and a fire brick in the middle to kind of disperse the flow.
Too much air volume up through the grate and you will consume a lot of wood and really heat up your stack!

[maple flats]

No need for nozzles, I run high pressure air in for AUF in a 4X heavy gauge stove pipe. It enters the rear and goes toward the door to 6" before the front. In that pipe I have 3 rows of 5/16" holes, 1 top center and 1 facing each side towards the outer edge of the grates. The holes are 3" apart. With a squirrel cage blower you might find that size holes too small and you may need to remove ash daily but it will work fine.
If you do however decide to go with the nozzle method, they will not burn, in my AOF my nozzles stick out thru the refractory, from 1/2" to about 1 1/4". Years ago I was thinking I'd saw the excess off, but didn't because of the vibration that would generate. Then I said, they will burn back to the brick in time. After several years nothing has burned, they look the same as when newly installed and it gets far hotter just above and in the intense flame than under the grates. I believe the cold air or slightly warmed air keeps then cool enough to prevent burning the nozzles.

[treehugger]

No need for nozzles, I run high pressure air in for AUF in a 4X heavy gauge stove pipe. It enters the rear and goes toward the door to 6" before the front. In that pipe I have 3 rows of 5/16" holes, 1 top center and 1 facing each side towards the outer edge of the grates. The holes are 3" apart. With a squirrel cage blower you might find that size holes too small and you may need to remove ash daily but it will work fine.
If you do however decide to go with the nozzle method, they will not burn, in my AOF my nozzles stick out thru the refractory, from 1/2" to about 1 1/4". Years ago I was thinking I'd saw the excess off, but didn't because of the vibration that would generate. Then I said, they will burn back to the brick in time. After several years nothing has burned, they look the same as when newly installed and it gets far hotter just above and in the intense flame than under the grates. I believe the cold air or slightly warmed air keeps then cool enough to prevent burning the nozzles.


I was just looking at your photo bucket pics of your nozzle system. How do you like the position of you ramp? I just set mine up similar to yours. I showed the pics to the guy that built the evaporator and he said to move the ramp back to 2/3 back. Everything I have read says bring it up to 1/3 past the front of the flue pan. How does your flue pan boil?

[treehugger]

No need for nozzles, I run high pressure air in for AUF in a 4X heavy gauge stove pipe. It enters the rear and goes toward the door to 6" before the front. In that pipe I have 3 rows of 5/16" holes, 1 top center and 1 facing each side towards the outer edge of the grates. The holes are 3" apart. With a squirrel cage blower you might find that size holes too small and you may need to remove ash daily but it will work fine.
If you do however decide to go with the nozzle method, they will not burn, in my AOF my nozzles stick out thru the refractory, from 1/2" to about 1 1/4". Years ago I was thinking I'd saw the excess off, but didn't because of the vibration that would generate. Then I said, they will burn back to the brick in time. After several years nothing has burned, they look the same as when newly installed and it gets far hotter just above and in the intense flame than under the grates. I believe the cold air or slightly warmed air keeps then cool enough to prevent burning the nozzles.

I put pics on the thread air manifold.

[maple flats]

My ramp works good, it boils super hard above the ramp and just past it, from there it is a full rolling boil to the back of the flue pan. I think if you move the ramp back you will not force the heat into the flues as well. But maybe Patrick Phaneuf knows better. My ramp ends at 20" back in the flue pan portion on a 5' long flue pan (1/3).

[treehugger]

My ramp works good, it boils super hard above the ramp and just past it, from there it is a full rolling boil to the back of the flue pan. I think if you move the ramp back you will not force the heat into the flues as well. But maybe Patrick Phaneuf knows better. My ramp ends at 20" back in the flue pan portion on a 5' long flue pan (1/3).

Yeah that's what I have set up now. I appreciate the input. Maybe I'll try it out before I change it.