Outdoor boiler smoke hood inline fan

[mooselake]

We have an Earth Outdoor Mountain Man 505 outdoor boiler that I installed a few years ago, and this fall built a shed around. The boiler must be part electronic, opening the door lets a lot of the magic smoke out. I had a local sheet metal shop fabricate a smoke hood, piped it to an outside wall, and added this inline fan. It worked great, for about 3 days, then the impeller disintegrated. After maybe 30 minutes run time total; the blower wheel separated from the backing plate. A bit of soot inside, but no sign of overheating. I was at work, and my wife was loading the stove when it quit. She has no idea what might have happened... On inspection other than a bit of soot residue I can't see reason why it failed. I can't see any evidence of overheating, and when in use the pipe never got more than varely warm to the touch.

Perhaps these "natural herb" grow tent charcoal filter fans aren't the best for smoke hoods The failed one claimed 440 cfm, which seemed about right; only a few wisps of smoke made it around the edges. The 6" round piping goes up two feet, over 7 to the fan (which was mounted at the wall), then through another couple feed outside. One elbow, and the outlet is just another piece of 6" round right now. We only use(d) it for a few minutes at a time when loading the stove, although I plan to add something like a spring timer. and add an automatic damper when we get the doors on the shed.

Does someone have a recommendation for a 6" inline fan that might last longer than a few days? A better approach?

Thanks!

Kirk

 

[Mike Fromme]

At the very least I'd replace it with a squirrel cage blower with metal blades and a motor mounted on the outside of the housing... Should be a able to find one with a ~250 degree rating for around $100.

If you don't ever want to worry about it again a power venter or induced draft blower would work for more $$$. Maybe you can buy just the replacement fan and motor from one? And not pay for the controls you probably don't need.

https://www.zoro.com/tjernlund-blow...gclid=CMGVgo6139ACFQdWDQodQpIC1w&gclsrc=aw.ds

 

[maple1]

When I had my cabbaged up hood thing going on with my old boiler, I just used an ordinary 6" in-line duct booster fan, that had metal blades. Think I Ebay-ed it, ones locally had plastic blades - the first plastic blade one I had seemed to get tired quick but I don't think that was due to the plastic blades, just that the metal bladed one was more rugged overall. Still have it somewhere in my basement, it was still doing it's thing when I dismantled everything.

 

[stee6043]

I think you just got a bad blower. I've used blowers such as the one you pictured in a handful of applications, including venting during loading, and never had any problems over years of service.

Though I must say with all that daylight coming in from your roofline I'm not sure why you need a vent? This is a shed, right? Most folks (though clearly not all) build hoods for their indoor boilers. If I had a shed I don't think I'd have bothered with venting...

 

[mooselake]

@stee6043 - I agree with you about the bad blower, don't know if it's a design defect (it was well rated on Amazon but maybe the raters were sampling their own product...) or just drew the QA short straw. It's got a light soot layer inside, don't know if the big A will take a return.

The shed was a concrete slab just over a week ago, and it's a work in progress. It's on the front of, and shares a wall with, a woodshed built in the '50s or '60s that was getting pretty rough. The old shed had sunk up to a foot into the ground; the worst walls have been jacked up and the sills (rough tamarack afaik 2x4s sitting on the ground) replaced with rough on top of treated 2x6, and another round of jacking/rebuilding, etc will happen in the spring. The plan is to insulate and line (drywall, metal, ???) the new shed and use it to cut some heat loss from the OWB, add a warm place to dry more wood, skip that whole loading in the blizzards thing, and maybe have a place to hang out (or hide after ticking off the wife ). Creosote brown, like most of the OWB sheds around here, wasn't the first choice of color schemes. Need to solve the smoke problem before going much further. It's one of those trial and error/spare time type projects, and the daylight will be fading as it progresses. Now to come up with a name - if the gasser people have Garn Barns is this an Earth Berth?

@maple1 - I've been looking hard for a inline blower with a metal blower cage, but must be in the wrong places. The Tjernlund M-6 looked like it might have one. Their tech support said it was plastic when I called but said it should do fine (they suggested the AD-1 if the smoke was over 140F). After being burned once I'm a bit gun shy. Those power venters are beyond the current budget, plus the pipe was just barely warm to touch when it was running. It sucked a lot of room (currently near freezing) air along with the smoke cloud.

@Mike - I could replace the elbow with a squirrel cage blower, but I'm not sure how to adapt it to 6" round pipe. Any suggestions, plus what's a good recommendation for the blower? I have a Grainger account.

Thanks for the help!

Kirk

 

[maple1]

http://www.ebay.com/itm/6-Inline-Du...019502?hash=item4883a11dae:g:XL8AAOSw9r1V98vi


That's what I got. Won't suck your doors in, but it seemed to work for me.

 

[mooselake]

@maple1 - Can I put a couple of these in series to get some extra airflow, if one isn't enough. My OWB is essentially a fire in a box of water, with a smoke pipe that extends almost to the bottom (yeah, not very high tech). When the door's opened all that smoke comes out the front.

What to do about that is another topic...

Kirk

 

[maple1]

Probably could?

 

[mooselake]

@maple1 - Thanks!

Kirk

 

[Mike Fromme]

If you go the squirrel cage route may need a duct collar or square to round 'ceiling boot' to make the connection.

 

[stee6043]

Be careful that you don't create so much negative pressure inside your shed that you end up making your smoke problem worse...

 

[mooselake]

Thanks, Mike. It really helps to know the correct name. I've been looking at squirrel cage fans on both Amazon and Grainger (haven't gotten to eBay yet). An overwhelming number of choices but not much luck finding one that looks like it might work for less than a couple hundred bucks. Can you suggest somewhere else to look.

@stee6043 - Yeah, that could be a problem once the shed gets closed up - right now, besides the daylight at the roof there's a 6' square hole into the woodshed, and a rough door opening on the other side. I was randomly speculating about somehow using that 6" pipe through the wall as part of an oa inlet, maybe with a T, a damper or two, some flexible ducting, and one of the newly name discovered duct collars on the boiler's draft fan. Might as well use that pipe for more than 15 minutes a day. The vent and draft wouldn't run at the same time. The draft fan is in the stove's door and moves with it so it might not be practical. No way I want to make the shed look like the recently posted collapsed sidearm pipe.

 

[mooselake]

Found a 6" backdraft dampers (item 4JA26) and duct collars (4JA17) on closeout at Grainger, and snapped up a couple of each, plus some half inch threaded rod to help close up some of those inter-building gaps. Grainger closeouts are one of my favorite shopping places (we have a free shipping account), but a bit prone to "that looks like I might be be able to use it someday" and Mrs. Moose is skeptical about the storage/find it again situation. You do need to read the description closely, anybody need some left hand 1/4-20 threaded rod, have a bundle of 6 footers. OTOH they were really cheap...

Also ordered an inline duct fan that I suspect won't be the final answer but will get me by until then. After that it'll be repurposed to help the laser engraver wimpy vent. Foot of snow forecast today...

Still not much luck with a squirrel cage blower, way too many choices and my iPower fan demonstrates that choosing one based on reviews and pictures isn't the best choice.

Kirk

 

[mooselake]

Quick update, got @maple1' s inline blower, helps but let's a lot of smoke past into the shed. Returned the broken blower, no word yet in refund. Still looking for the right sized squirrel cage blower.

Kirk

 

[mark123]

We have an Earth Outdoor Mountain Man 505 outdoor boiler that I installed a few years ago, and this fall built a shed around. The boiler must be part electronic, opening the door lets a lot of the magic smoke out. I had a local sheet metal shop fabricate a smoke hood, piped it to an outside wall, and added this inline fan. It worked great, for about 3 days, then the impeller disintegrated. After maybe 30 minutes run time total; the blower wheel separated from the backing plate. A bit of soot inside, but no sign of overheating. I was at work, and my wife was loading the stove when it quit. She has no idea what might have happened... On inspection other than a bit of soot residue I can't see reason why it failed. I can't see any evidence of overheating, and when in use the pipe never got more than varely warm to the touch.

Perhaps these "natural herb" grow tent charcoal filter fans aren't the best for smoke hoods The failed one claimed 440 cfm, which seemed about right; only a few wisps of smoke made it around the edges. The 6" round piping goes up two feet, over 7 to the fan (which was mounted at the wall), then through another couple feed outside. One elbow, and the outlet is just another piece of 6" round right now. We only use(d) it for a few minutes at a time when loading the stove, although I plan to add something like a spring timer. and add an automatic damper when we get the doors on the shed.

Does someone have a recommendation for a 6" inline fan that might last longer than a few days? A better approach?

Thanks!

Kirk

View attachment 189487 View attachment 189489View attachment 189488

This is not inline but it is the one used in the smoke hood made by AHS the Woodgun company. I am building a new setup and am going to order one.

https://www.acklandsgrainger.com/en/product/BLOWER-PSC-115-VOLT/_/R-GGE1TDR7

 

[mooselake]

Thanks, @mark123 , I appreciate the part number. Grainger lists the 1TDR7 as -20 to 104 degrees F - not really a problem when it's -15C (like right now..) but it's pushing it when I finally get the shed enclosed and insulated. Doubt that would be an issue for 10 minutes at a time, but the -20F might be.

Been winging it with the inline blower. Doesn't get all the smoke but trying to recover from the holidays before another shopping expedition. Other fan refund came through (my first from the big A). The closeout adapters I got are huge, over 12 inch diameter, but I've got tin snips and access to a bender.

OT, but we were gone for a couple weeks over the holidays, all three girls in the US at the same time and even the same place. Found somebody to check and feed the horse and pony, but nobody to keep the boiler going. Shut off the boilers draft fan by putting the control into cooling mode, packed the rear pump and plumbing chamber with some leftover fiberglass batts (it's just lined with that pseudo-insulation reflective stuff), and wished it luck. Came home to 100F water from the water heater sidearm and house propane boiler heat exchanger, warmer than I expected, and well fed livestock. Have been afraid to dig the propain tank out of the snowdrift and look at the gauge. Several feet of snow and -10F temps while we were gone (150+ inches for the season already), ended up driving a couple hundred miles to an open airport since ours was in a whiteout with 4 more days forecast - the drive wasn't bad after the first 20 or so miles.

Kirk