View Full Version : Steam hood Problem - Stack undersized or not tall enough?
twofer
03-03-2011, 10:38 AM
Did our first boil last night and promptly turned the sugarhouse into steamshack. The steam hood over the syrup pan is 30"x36" and has a 6" stack. The stack is through the middle of the roof ~2' but does not clear the peak. After the test boil produced too much steam we lowered it down to 9" above the syrup pan and it still had steam bellowing out the bottom and into the sugarhouse.
This is a wood fired arch and this is my first time running it so I'm worried about not being able to see the middle partitions and don't want to drop the hood down on the pan.
Need some help here from the MapleTrader brain trust. Is the stack undersized? Do I need to add more stack and get it higher to maybe increase draft? Am I SOL?
TIA
Did our first boil last night and promptly turned the sugarhouse into steamshack. The steam hood over the syrup pan is 30"x36" and has a 6" stack. The stack is through the middle of the roof ~2' but does not clear the peak. After the test boil produced too much steam we lowered it down to 9" above the syrup pan and it still had steam bellowing out the bottom and into the sugarhouse.
This is a wood fired arch and this is my first time running it so I'm worried about not being able to see the middle partitions and don't want to drop the hood down on the pan.
Need some help here from the MapleTrader brain trust. Is the stack undersized? Do I need to add more stack and get it higher to maybe increase draft? Am I SOL?
TIA
Interesting, are you sure there isnt anythign in the pipe! Second, I wonder what the outside temp was and if the pipe was cold. Like whe nI start my woodstove from a cold start, if my chimney is cold, it takes awhile for the cold air in the chimney column to be replaced with the warm air, ofter Iwill get smoke coming back into the house. Now I jsut burn one piece of paper first and it usually works ok
twofer
03-03-2011, 10:56 AM
Interesting, are you sure there isnt anythign in the pipe! Second, I wonder what the outside temp was and if the pipe was cold. Like whe nI start my woodstove from a cold start, if my chimney is cold, it takes awhile for the cold air in the chimney column to be replaced with the warm air, ofter Iwill get smoke coming back into the house. Now I jsut burn one piece of paper first and it usually works ok
Even after finishing up at 3am this problem kept me up all night and something possibly being stuck in the pipe kept rolling around in my head. First thing before I headed off to work I weaseled my way between the syrup pan and the hood and took a peek, nothing. I was actually hoping there was something stuck up in there. :)
SSFLLC
03-03-2011, 11:05 AM
I thought these hoods where sappose to sit on the pans. Thats why every body puts windows in them.
Only the flue pan, not he syrup pan
RileySugarbush
03-03-2011, 11:27 AM
Did you have a door or window open to let air in for your arch?
Our hood is the same size and works fine with a 6" stack when it is sitting on the pan. When we open the hood doors steam doesn't come rolling out, so we have good draft.With a raised hood, I bet you do need a bigger stack, or block off a few sides.
Maybe get some polycarbonate sheet and make some hanging panels for the sides to close it up some. Home Depot has it for screen door windows
yeah, I would think that the hood would need to be a few inches if not more wide than the width of your pans right?
twofer
03-03-2011, 11:39 AM
Did you have a door or window open to let air in for your arch?
Our hood is the same size and works fine with a 6" stack when it is sitting on the pan. When we open the hood doors steam doesn't come rolling out, so we have good draft.With a raised hood, I bet you do need a bigger stack, or block off a few sides.
Maybe get some polycarbonate sheet and make some hanging panels for the sides to close it up some. Home Depot has it for screen door windows
Yeah, we had a window cracked and eventually it got so bad that we had all the windows and door open.
interesting, you might need to add some kind of forced chimney draft
morningstarfarm
03-03-2011, 12:56 PM
for my 2x6 this year I built a prototype hood out of 2x2 wood and a poly tarp...made it 4x7 so that condensation would stay out of pan...now, my hood is about 20" above the pans..I like to be able to see into them...my roof is a shed style so I had to put in a power vent fan...works pretty well...got a power vent at home depot and used a piece of 7" and 8" light ductwork to make the 15" stack...this summer I am making it out of stainless, but will add a second vent fan and make the hood deeper to cut down steam rollover...good luck
Ausable
03-03-2011, 03:49 PM
for my 2x6 this year I built a prototype hood out of 2x2 wood and a poly tarp...made it 4x7 so that condensation would stay out of pan...now, my hood is about 20" above the pans..I like to be able to see into them...my roof is a shed style so I had to put in a power vent fan...works pretty well...got a power vent at home depot and used a piece of 7" and 8" light ductwork to make the 15" stack...this summer I am making it out of stainless, but will add a second vent fan and make the hood deeper to cut down steam rollover...good luck
Chris I was wondering how the fan motor holds up against all that moisture - Does the steam seem to bother it any? I was rolling that same idea around and didn't know if it would work -- might do it yet. Did add another 2 feet to my stack today -- Now I gotta wave a magic wand and make some sap ---- Mike
james ferguson
03-03-2011, 04:06 PM
i had same thing with my home made hood steam got so hot we could not breath steam would be two ft off of floor i ended up tacking a 2x2 ft box fan and wired it to top of stack on out side and that worked great rig size was 3x10 oil new one is 3x10 with fact hoods and preheater
Southtowns27
03-03-2011, 05:27 PM
What was the outside temp when you were boiling? We boiled Monday night and I have never had steam so bad in the shack, it was solid all the way down to our knees. I thought about it for awhile then realized that the temps had dropped to the upper teens with high humidity outside. Maybe you had similar weather conditions?
twofer
03-03-2011, 10:20 PM
What was the outside temp when you were boiling? We boiled Monday night and I have never had steam so bad in the shack, it was solid all the way down to our knees. I thought about it for awhile then realized that the temps had dropped to the upper teens with high humidity outside. Maybe you had similar weather conditions?
Yes, it was 16 degrees when we were boiling. It had dropped from a high near 40. You might be onto something. We should be boiling again tomorrow or Saturday so we'll see how it goes before I do anything drastic.
morningstarfarm
03-03-2011, 10:47 PM
its a roof vent fan from home depot..it lasted all last season and is still going strong this year...
Haynes Forest Products
03-03-2011, 10:58 PM
Steam is heavy Real heavy. You need a bigger pipe to get it moving. Skip the fan you will create a new problem you will be posting a new thread about Flue stack fan problems. Cold air flooding into a hot room full of steam can cause a torrent of cold heavy steam that WONT LEAVE. What window you open and how much you open it is an art form that can be the difference between getting the steam out. This will sound strange but there is a big difference between HOT steam And COLD condensate laden air...........WHAT yes at some point the air is so heavy with cold condensate that it wont rise it will fall to the ground. You need a hot sap shack to get the draft you want. You also want makeup air to replace the steam leaving the shack.
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