Cherry red stack

[steve J]

I cam close to having a stack melt down. I had blower running on high my rig only has 6 inch pipe. If I use 8 inch would this prevent this or would I just push all the hot air up stack.

[Brent]

Someone should report you for carbon emisions. You're blowing more heat up the stack than you're boiling with.
Bin der ... dun dat :D

[500592]

How bout a damper in the pipe

[GramaCindy]

I cam close to having a stack melt down. I had blower running on high my rig only has 6 inch pipe. If I use 8 inch would this prevent this or would I just push all the hot air up stack.

Steve, only my first boil, but I too have a Mason, but a 2x4 and we have the 6" stack, I used a "blower" on low but we did install a damper and I had it at 45* or half closed when firing at high. Worked great for me so far, hope this helps.

[TapME]

I cam close to having a stack melt down. I had blower running on high my rig only has 6 inch pipe. If I use 8 inch would this prevent this or would I just push all the hot air up stack.

When you can see through the stack you know you have a problem (white hot). Turn the blower down a little so the heat stays closer to the pans. But isn't something when you can do that.

[steve J]

If I put a damper in the pipe would that not force it to get even hotter? Also I did build a false wall about 8 inches from the rear but I did it sort of in a hurry and I suspect I could have built it a bit higher would that not help some. I have not issue running the blower on low or med but when I was able to run it on high I was getting 17 gal per hour evaporation on med I am between 14 and 15. I need all the evaporation I can get as I am pulling more sap then I can boil.

[500592]

Put the damper as close to the bottom of the stack as possible

[Starting Small]

I know the rule of thumb is to have your stack twice the length of your pans. Why is this? Would their be any benefit to having it longer than 2X?

[Jec]

It is for a good draft. You need a good pull for starting a fire and keeping it roaring. 2x the lengh is perfect for good draft but not too much. You can go a little higher if needed.

[BoarsNest]

I've had mine glowing red and it seemed to be just fine. My preheater tank wrapped around the stack and I had put insulation around the stack to keep it from burning the sap in the preheater. Everything worked great......until I took everything down and found about a big hole in my stack behind the insulation. I would watch it closely.

[maple marc]

I think you're wasting heat up the stack--way too hot, probably 1600 degrees. Part of the problem is your short evaporator--they just don't operate as efficiently as longer ones. You're not gaining any boiling rate after a certain temperature, just wasting wood. Back off the blower, or even shut it off. I went through this phase the first year with my 2x4. I didn't know better. With a tall 10" stack I had to run with the draft door completely shut so I wouldn't over-heat. Also depends on your wood--you may have really nice dry stuff.

[Starting Small]

What exactly is a damper and what is its purpose?

[maple flats]

A damper is a flat piece, usually cast iron, that it in the stack. turning it to block or slow the movement of smoke (and gasses). I have never had a damper in the stack on an evaporator.

[wiam]

It makes no sense to me to put in a blower and a damper.

[mapleack]

It makes no sense to me to put in a blower and a damper.
Exactly. You don't want a damper in a wood fired evaporator. If the stack is getting too hot either slow down your blower if possible, or install a diverter in the blower duct to cut down on your airflow. It sounds like you're after the fastest evaporation rate, not wood efficiency. I've been there too. If it were me I'd just run it flat out and look for a bigger rig for next year!

[Brent]

If you brouse all .... ALL the evaporator manufacturer's catalogs, you will not see a damper in any of them.
None, not one.

[Ausable]

I cam close to having a stack melt down. I had blower running on high my rig only has 6 inch pipe. If I use 8 inch would this prevent this or would I just push all the hot air up stack.

Steve - You have already been told this - but you need less forced draft. Electric Generating Plant Boilers have louvers on both the Forced and Induced Draft Fans - to allow for the most efficient combustion of the fuel - inside the boiler. If You keep the forced draft the same on your rig and add an 8" stack - You are right - less back pressure - but - more heat up the stack. If you put a damper in your stack and close it a little and have the same amount of forced draft you have now - the back pressure will be even higher and smoke will be coming out every hole and crack in the arch. So --- Easy solution - restrict the air flow from your forced draft Blower until you get a good hot fire in the arch - it will vary some with the amount and type of wood you are burning - but - you will find a good all around air setting that works most of the time. ------Mike---