Exhaust fan/hood

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Bad Wolf

Bad Wolf

Minister of Fire
Jun 13, 2008
523
Eastern CT
I'm going to make a second pass at constructing a hood to blow the smoke out of the basement when I open the furnace door. Last year I put together a hood I made from a floor duct and some 4" exhaust tubing and a small in line fan I got at Home Depot. I found I needed to make the hood itself bigger and the plastic blades on the fan tended to get soft with the hot air/smoke coming of the furnace.

Does anyone know of a fan with metal blades? I think I can fix the other problems.

Thanks
 
Greg H said:
I'm going to make a second pass at constructing a hood to blow the smoke out of the basement when I open the furnace door. Last year I put together a hood I made from a floor duct and some 4" exhaust tubing and a small in line fan I got at Home Depot. I found I needed to make the hood itself bigger and the plastic blades on the fan tended to get soft with the hot air/smoke coming of the furnace.

Does anyone know of a fan with metal blades? I think I can fix the other problems.

Thanks
Click to expand...
Radial blade blower. I would look on Ebay as these can get expensive elsewhere. They have good static pressure, the trick is to find a smaller one, good luck, Randy
 
I think "Fantech" make them out of metal; rated to 140 °F. If you have a Grainger by you, take a look at them there.

NOTE : They are Expensive!
 
I use an old blower motor & cage from a forced air furnace. Piped thru the wall with 12x8 duct. It moves the air (and also the heat out of the boiler room). Becarefull, depending what is left in your furnace, it will suck flame out the door.
 
Before fans, hoods, blowers, etc., have you tried just opening a window to provide more natural draft? Also, before opening the firebox door all the way after opening the bypass damper, opening it just a bit and then pausing a few seconds to give the natural bypass draft time to be fully established? It is quite uncommon for my Tarm to spill smoke when I've done these.
 
No window in the basement. Depending on how well the fire is burning I sometimes don't get any smoke but other times I can get quite a bit. I found a different fan on ebay that is rated to 266 degrees rather than the 140 that the Home Depot one was. I was going to add a microswitch on the door so it would come on when ever the door was open.
 
Greg H. I can relate to your smoky problem, my new Harman has the same symptoms. I have a stairwell within six feet of my furnace, sometimes I feel it drafts better than my chimney? I’ve also wondered if I enclosed my furnace room then used a outside air kit or a small fan to the pressurize the furnace room if it would force the smoke up the chimney better when loading the fire box?
 
When I did a little research on industry standard (maybe code also) for a make-up air vent for my Tarm, the minimum standard was a little larger than a 12" x 24" opening, which amazed me, as the draft fan is only 150 cfm. Make-up air is based on boiler hp, not the cfm of the draft fan. When the Tarm is being fired, I open a 24" window about 12", as I assume I have other air infiltration. I have observed that the Tarm burns noticeably better with the window open than with the window closed. As noted above, window open results in little or no smoke emission into my shop when the firebox door is opened.
 
I'm new to running a wood boiler, but wouldn't an exhaust hood with a fan to the outside create a negative pressure in the boiler room causing more smoke to be drawn into the room?
 
When I get my Econoburn running I am going to try Positive Pressure Ventilation.

You will have to be careful when feeding fire fresh air but I can't imagine why it won't work.

1. Open Bypass

2. Open Fire box door

3. Use a Box fan or similar to seal opening of firebox with the exhaust from fan. (It should be several feet from firebox opening)

The Exhaust from the fan will create a positive pressure in the firebox. If the air curtain seals around the edges of the opening the smoke will have no where to go but up the stack.

We use it in Firefighting all the time. Works well, but like I said you need to be careful feeding oxygen to the fire. We need to know where the Fire is and where it is going to exit or it can't be used.

With a Boiler you know both, Its in the Firebox and its exit is out the bypass.

BUT PROCEED WITH CAUTION!!! IT COULD CAUSE A BACK DRAFT IN STOVE IF CONDITIONS ARE RIGHT!!!!

gg
 
goosegunner said:
When I get my Econoburn running I am going to try Positive Pressure Ventilation.

You will have to be careful when feeding fire fresh air but I can't imagine why it won't work.

1. Open Bypass

2. Open Fire box door

3. Use a Box fan or similar to seal opening of firebox with the exhaust from fan. (It should be several feet from firebox opening)

The Exhaust from the fan will create a positive pressure in the firebox. If the air curtain seals around the edges of the opening the smoke will have no where to go but up the stack.

We use it in Firefighting all the time. Works well, but like I said you need to be careful feeding oxygen to the fire. We need to know where the Fire is and where it is going to exit or it can't be used.

With a Boiler you know both, Its in the Firebox and its exit is out the bypass.

BUT PROCEED WITH CAUTION!!! IT COULD CAUSE A BACK DRAFT IN STOVE IF CONDITIONS ARE RIGHT!!!!

gg
Click to expand...


Goose: Have you tried the process you described?, and what's the result?

Thanks.
 
I have tried it some. It does not work as well as I hoped with the fan I have. Not sure exactly why yet. Most likely because of the small flue exit for the bypass.

I need to experiment more but for now I have been just loading it without the fan. At times I get way too much smoke in the room.

I am so glad I did not have the option to put it in my house. It would definitely be a problem. I don't think they are designed very well to be put in a home.

gg
 
Hi Goose
I have a new econoburn 200,i'm going to fire it here soon.I have been reading threads since dicovering this site.One thread i was reading,the someone mentioned picking one boiler over their first choice because the top of the wood camber had a flat ceiling that continued to the door opening.Anyhow i looked at mine the otherday and seen the same design on mine.I'm going to try to install a smoke curtain on mine befor i get it going.I'm going to hinge it off the air supply ducts that come near top.
Seeing how i'm not burning yet,is there a lot of smoke coming out of yours when you reload?
I'll do a post when i figer out how to mount.
Thanks Thomas
 
salecker said:
Hi Goose
I have a new econoburn 200,i'm going to fire it here soon.I have been reading threads since dicovering this site.One thread i was reading,the someone mentioned picking one boiler over their first choice because the top of the wood camber had a flat ceiling that continued to the door opening.Anyhow i looked at mine the otherday and seen the same design on mine.I'm going to try to install a smoke curtain on mine befor i get it going.I'm going to hinge it off the air supply ducts that come near top.
Seeing how i'm not burning yet,is there a lot of smoke coming out of yours when you reload?
I'll do a post when i figer out how to mount.
Thanks Thomas
Click to expand...

Depending on the amount of wood remaining, It can be terrible if there is any left. It is best to only open with coals.

Even with coals only if you don't hustle it smokes bad. The problem is wood starts to ignite right away. I try to layout the amount I need right next to the boiler. Open the door and quickly load. I usually leave the door on the boiler room open.

I need to try positive pressure with a different fan and some different fan speeds. The fan I have might be over pressuring the firebox for the size of the flue outlet. smoke slips out around the air cone.

gg
 
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