Chimney fan

GG ,
Do you know the price on this?
I added an inline 6" draft fan in the shroud I made. I wanted to create a draft with the fan before I opened to door to my outside boiler. The fins were made of plastic and the heat melted them, even after moving a second fan further ftom the heat source.

Sounds like I have a similar setup to Meheat. My inline fan is still going - has plastic blades also that haven't melted yet - but it took a few cracks to the side of it to get it started this fall. I think it's on its last legs, so I got one of these a month or so ago:

http://www.ebay.ca/itm/ws/eBayISAPI.dll?ViewItem&item=230424636322

Came real quick, and is a very solid looking unit, at least compared to the old one I have. Tag on it says 'thermal protected' (whatever exactly that means), and also says approved for temps up to 266°f. Mine is still in the box, waiting for the old one to finally quit, but I was impressed with it when I got it. I plan to just get a couple of 6/8in. adaptors for it.

why not buy something made for the job.

http://www.draftinducers.com/ad1.htm

I guess my suggestion has nothing to do with the specific thread title - chimney fan - but more with the related dealing with spill out smoke by a hood.

Maybe if someones chimney draft is not up to what is spec'd for their unit, they should investigate a draft inducer - but if they are getting spill out with a spec'd draft, they should investigate a hood? I could see a draft inducer starting a chimney fire (although I didn't see specs on how much it does increase draft), if combined with lots of creosote buildup in the wrong places and it creating an overdraft condition - but that would also be a function of poor operation & lack of maintenance, and not likely to occur with a gassifying unit.

I think I'd also anticipate problems with the one in the OP link getting dirty/gunked up & not working, since it seems to be right at the place where most of the residue/creosote would accumulate? Haven't seen one in use or know of anybody with one, so not sure on that.

That is my plan as well. Run the inducer only when loading. Small price to pay to keep the smoke down.

JP11 said:

why not buy something made for the job.

http://www.draftinducers.com/ad1.htm

Click to expand...

Because they dont work. Even the ones they make for the EKO dont work.

Rob

JP11 said:

why not buy something made for the job.

http://www.draftinducers.com/ad1.htm

Click to expand...

Tried one of these on my Econoburn 100 and its true they don't work, still get smoke if I open to load at the wrong time. I have it switched on automatically when I open the door and off when the door is closed and boiler is on.

Biomass 40 - my experience has taught me to leave it alone and figure out by timing when to load. If I do go to load it and there are still flames, I leave it alone because it will spew smoke when i open the door. If there are only hot coals then it is okay to open. Short answer - load it and leave it alone.

"Even with only coals I need to be fast because the wood starts smoking and burning really quick once I put it in."

There-in lies the problem.. The mass of energy that is suddenly released when combustible wood is placed on 1000*f (or higher) coals is usually greater than any simple draft fan is designed to handle by itself. If there is room/compatibility in your boiler to install a "baffle" style plate to reduce the the size of the open door and force the sudden gas expansion up the chimney you would aid the draft fan in doing your desired smoke control. Otherwise you're apt to spend some big bucks to get a fan that will handle the expanding gasses. There should be a calculation somewhere that will give the amount of energy and cubic feet of air displacement that a given square feet of x degree coals will give off when given a new source of fuel. A rough guess would be muiltiply your firebox cubic measurement by 10 or 50 or 100 and give it a per second flow and see if the blower you are considering is big enough to handle the flow. Most blowers are rated cfm a small cf per sec while the firebox is spewing out at x feet per second. Another way to look at it is.. is the flue size large enough to take the suddenly released gasses without aid and if not how much aid (cfm/sec) will it require to overcome the suddenly released gasses. i.e. The few gassers I have seen did not have a baffle plate in the primary combustion chamber to force heat up the chimney when the door was open. Most of the flue openings were at or near the level of the top of the open door (therefore not creating a pressure zone pushing the smoke up the chimney). A baffle plate has to temporarily restrict the door opening to at least the size of the flue openinng but well below the flue openeing to give the flue the opportunity to handle the gasses (the sudden burst of energy will fisrt expand upward into the chamber and try to get out of the flue). With a baffle plate creating a fresh air opening far enough below the opening of the flue opening you will generate a pressure and increased velocity in the exhaust gasses in the chimney that will greatly aid in temporary boosted draft. Adding the booster fan to that sudden burst will geatly reduce any smoke and perhaps eliminte it altogether. (unless you want to just stand there and watch). :bug:

what about just pressurizing the boiler room? Turn on a fan that blows into the room a few minutes prior to loading. It's important to keep in mind that the draft may be insufficient because there is not enough make-up air, not because of a chimney problem.

The Tarm Solo Innova and the Fröling FHG both have induction fans, so smoke roll out is essentially eliminated, but with the Solo Plus and most other boilers on the market, smoke roll-out can be a small or large problem.

Anyone ever try pressurizing the room?

I used to own/operate an EKO 40 and even with a draft inducer fan it still smoked heavily if I opened it up at the middle of a burn.

I since then have sold it and now heat my house with an effecta lambda 35 with a negative draft (fan at rear of boiler) system.

This boiler has a special "smoke evacuation port" just above the door opening which sucks the escaped smoke directly out the chimney.

However, I have noticed that I must open up the door slowly or I do get some smoke into the room, especially when the boiler is really running well/hot and gasifying the wood.

Brian

I have the same problem. Even loading quickly with my wood wagon right next to the door still lets a large amount of smoke escape placing it on those hot coals. I usually quit loading at about 3/4 full now (no storage) because I don't need a full load but that last 1/4 would probably more than double the smoke that escapes. I think a baffle would just get in the way making the whole process take longer especially if you are trying to fill it full. I usually swing the door close to closed when grabbing the next handful and this does help. I think a smoke hood like many have built here is the answer. I will be looking for some type of fan that I can put in the "attic" of my pole barn that can be switched on just during the loading process. Should be able to vent the smoke into the attic and let it dissipate throught the vents in the ridge and eaves.

There don't have to be a chimney problem to have smoke force it's way out of an open door. A perfectly drafted unit will still have trouble with the amount of energy that a coal bed with new fuel can generate. If the fire box floor, where the coal bed is, is 17" x 21", like my EKO40, then the coal bed is 7 x greater than the flue opening. Pressurizing the room to overcome the sudden energy potential will take quite a blower and a good source for outside air to supply the volume to provide the pressure. It's just a minor pet pieve (sp?) of mine that the mfg's don't supply a baffle with their multi $k units. I had a wood furnace that had a built in baffle because common sense toward making the customer happy prevailed in the thinking of marketing and engineering. Euro mfg's think smaller storage than most people on this forum do and as a result you will have to open the combustion chamber and reload the boiler while there is still an ample coal bed which can and will generate a sudden volume of smoke too large for the flue size to handle just so storage can be brought up to temp. My old wood furnace handled the surge well without any booster fan and it had about 8' slow pitch to the chimney outlet. When a baffle plate is in the down position it restricts the available air to the coal bed and immediately brings the fire back into the parameters of the draft design. As a side note OWB's could use a baffle plate too.

huskers said:

I have the same problem. Even loading quickly with my wood wagon right next to the door still lets a large amount of smoke escape placing it on those hot coals. I usually quit loading at about 3/4 full now (no storage) because I don't need a full load but that last 1/4 would probably more than double the smoke that escapes. I think a baffle would just get in the way making the whole process take longer especially if you are trying to fill it full. I usually swing the door close to closed when grabbing the next handful and this does help. I think a smoke hood like many have built here is the answer. I will be looking for some type of fan that I can put in the "attic" of my pole barn that can be switched on just during the loading process. Should be able to vent the smoke into the attic and let it dissipate throught the vents in the ridge and eaves.

Click to expand...

DONT DO THIS! 1 hot ember and you will be looking for a polebarn builder! If you want a vent hood do one like mine it works pretty good. https://www.hearth.com/econtent/index.php/forums/viewthread/64971/



Rob

I have exposed myself to enough crap after 25 years of firefighting, I don't need add more trying to heat my house.

Click to expand...

Should have put on your PPE ....LOL

Rob

taxidermist said:

huskers said:

I have the same problem. Even loading quickly with my wood wagon right next to the door still lets a large amount of smoke escape placing it on those hot coals. I usually quit loading at about 3/4 full now (no storage) because I don't need a full load but that last 1/4 would probably more than double the smoke that escapes. I think a baffle would just get in the way making the whole process take longer especially if you are trying to fill it full. I usually swing the door close to closed when grabbing the next handful and this does help. I think a smoke hood like many have built here is the answer. I will be looking for some type of fan that I can put in the "attic" of my pole barn that can be switched on just during the loading process. Should be able to vent the smoke into the attic and let it dissipate throught the vents in the ridge and eaves.

Click to expand...

DONT DO THIS! 1 hot ember and you will be looking for a polebarn builder! If you want a vent hood do one like mine it works pretty good. https://www.hearth.com/econtent/index.php/forums/viewthread/64971/

Rob

Click to expand...

+1. I don't think you're going to want to vent any kind of smoke hood into your attic. For a whole bunch of reasons. Not the least of which is that I'd bet it would never pass code.

I think the progression of "smoke issues" is really rather interesting:

Year 1 - Live with smoke, complain about it a little, but still very happy to have cheap heat.
Year 2 - Invest in smoke hood and/or draft fan. Find out that perhaps neither of these solutions really solves the problem 100%, but still very happy to have cheap heat.
Year 3 - By now we've learned a fair amount. Loading the boiler only when it's down to coals is the real ticket to smoke-free happiness. Barely turn on that expensive draft fan now. Load the boiler with enough wood each time so its very low when the time comes for the next load. Load planning...
Year 4 - Laugh when you look at the silly draft fan that does nothing and wish you could have that $100 back.

Here's my custom fabbed hood:



And the duct and in-line fan out thru the window space:



Hood is an ordinary duct boot, with sheet metal screwed extensions made of flashing, the duct is ordinary flexible metal 6 inch - I slapped this together in a hurry one Saturday. I get 95% of the smoke spill with this. The fan that is on its last legs doesn't do much when the wind is blowing against it from outside, the new one (link posted earlier in thread) will be much better. If there's much of a fire when I've got the door open, the boot can get hot, but not much of that heat makes it as far as the fan. Total cost less than $50. I happened to have a window right there so it was an easy thing to do. I also run it when cleaning out the ashes.

stee6043 said:

taxidermist said:

huskers said:

I have the same problem. Even loading quickly with my wood wagon right next to the door still lets a large amount of smoke escape placing it on those hot coals. I usually quit loading at about 3/4 full now (no storage) because I don't need a full load but that last 1/4 would probably more than double the smoke that escapes. I think a baffle would just get in the way making the whole process take longer especially if you are trying to fill it full. I usually swing the door close to closed when grabbing the next handful and this does help. I think a smoke hood like many have built here is the answer. I will be looking for some type of fan that I can put in the "attic" of my pole barn that can be switched on just during the loading process. Should be able to vent the smoke into the attic and let it dissipate throught the vents in the ridge and eaves.

Click to expand...

DONT DO THIS! 1 hot ember and you will be looking for a polebarn builder! If you want a vent hood do one like mine it works pretty good. https://www.hearth.com/econtent/index.php/forums/viewthread/64971/

Rob

Click to expand...

+1. I don't think you're going to want to vent any kind of smoke hood into your attic. For a whole bunch of reasons. Not the least of which is that I'd bet it would never pass code.

I think the progression of "smoke issues" is really rather interesting:

Year 1 - Live with smoke, complain about it a little, but still very happy to have cheap heat.
Year 2 - Invest in smoke hood and/or draft fan. Find out that perhaps neither of these solutions really solves the problem 100%, but still very happy to have cheap heat.
Year 3 - By now we've learned a fair amount. Loading the boiler only when it's down to coals is the real ticket to smoke-free happiness. Barely turn on that expensive draft fan now. Load the boiler with enough wood each time so its very low when the time comes for the next load. Load planning...
Year 4 - Laugh when you look at the silly draft fan that does nothing and wish you could have that $100 back.

Click to expand...

Ok, I guess I asked for that. I've never considered the draft inducer fans. Almost everyone here that bought one says they are junk. Draft is not a problem. Just loading the last 1/2 of the firebox even when it is down to coals is where I get the smoke. Swinging the door shut between handfuls helps but a good amount still escapes especially when trying to fill it full which I anticipate doing with storage. My cold startup procedure involves getting a couple very small dry splits burning hot for about 20" with lower door open and then filling it to the top. I think the smoke hood is way to go eventually. I will keep my eyes open for the materials and and a blower to make it work. If I can find roof mount that fits between the ribs on the steel roof I will go that route. Something like that yellow portable one for $99 in another post might be a good choice as well venting right through the wall outside with a screen or cap of some type. Might be able to make it removable and use it for something else in the summer months.

huskers said:

I have the same problem. Even loading quickly with my wood wagon right next to the door still lets a large amount of smoke escape placing it on those hot coals. I usually quit loading at about 3/4 full now (no storage) because I don't need a full load but that last 1/4 would probably more than double the smoke that escapes. I think a baffle would just get in the way making the whole process take longer especially if you are trying to fill it full. I usually swing the door close to closed when grabbing the next handful and this does help. I think a smoke hood like many have built here is the answer. I will be looking for some type of fan that I can put in the "attic" of my pole barn that can be switched on just during the loading process. Should be able to vent the smoke into the attic and let it dissipate throught the vents in the ridge and eaves.

Click to expand...

When trying to meeet potential with storage there is no real point in filling the boiler combustion chamber to the max. You are right that a baffle will prevent loading the box full but since you are going to have to load (at least partially) again to get sotrage to temp is there a need to fill the box to the brim once and then partially when two partial loads are the same amount of wood? (storage size may dictate a third load or more) Baffles do have their draw backs though they do not really impede a 3/4 filling and they do quickly and economically reduce smoke. A smoke hood is easily a great addition to the current smoke problem and if I may be so bold I think for the price we pay for a system unit and install a smoke hood should be part of the package and not a price tag booster. But if a hood is not in the offing then at least a baffle should be. Well constructed baffles are easily removed if they are deemed to be an inconvenience.