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Post in 'The Boiler Room - Wood Boilers and Furnaces' started by infinitymike, Mar 30, 2013.
Here is a good read from Woodstock
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Even if there is a problem smell at full burn (something I've also not experienced), adding storage would cut the times you're actually burning at least in half (my experience - right now I'm only burning about 4 hours a day). The rest of the time your fire is OUT, so there is nothing to emit. Then you could schedule the burn for when it's most likely to not offend.
Ugly smell at full burn seems puzzling to me also. What is it about the Gun that makes it specific to it? Is it moving air through so fast it doesn't have a chance to burn completely? Can adjustments to fan speed, air openings etc. not be made to tune it out?
Regardless,simple chimney/cap mods are what I'd be doing right now for starters - quick & easy (& cheap) to try.
"During the off cycle, wood gas inside the firebox condenses on the inner walls forming a solid that will eventually fall off. This combines with the remaining fuel thus adding energy that in many other boilers goes up the chimney." quote from wood gun web site
This "SOLID" I would think is creosote.
I was thinking after my last post that perhaps a diet change may solve the problem. I may be all wet but what I believe is happening is that at full burn, the oxygen is used up in the primary combustion and there is not enough left to completely combust (if that's a word) the gasses in the secondary since there is no means of supplying secondary air in Mike's boiler. Perhaps (dare I say it) adding wood with a little higher moisture content would make for a smaller fire which would then use less combustion air in primary and allow more to flow to the secondary tube allowing all the gasses to ignite. There may be other odors that are emitted but the most offensive one to me was when my Wood Gun was fireing full bore. Other problems will arise with this "fix" but it sure beats abandoning the wood boiler in favor of oil.
I think the "other boilers" they're referring to don't include other gassers.
Creosote burns with a unique smell and it burns hot. with a short stack on the chimney any applaince will have incomplete combustion. the distance to the diagonal nieghbor maybe less than the 100-150(300-450') yards as stated. but the stack hieght is lower than the residence not served by the appliance.
Well, I am a bit dense but it seems to me this could be the cause of the sulfur/acrid smell as apposed to incomplete combustion of the wood load.
IF this is the case, then I take back my statement of storage not helping the situation as this scenario would point right at idling as the cause of the smell. I think this is what Taylor was getting at earlier but like a say I am a bit dense.....
I would think an easy way to put this to the test would be to thoroughly clean the upper chamber of the WG to eliminate the chunks o' creosote. Then make a fire and see if the smell changes or goes away.
Worth I shot,
If he is burning to storage there would likely be no visible smoke just the smell. It would be much harder for the city/neighbor to pinpoint Mike as the smelly one if they never saw any smoke coming out the chimney.
Storage might not end the smell but it has a good chance of ending his problem.
My Eko burns the creosote on the walls of the upper chamber. I know it is burning because any deposit with any amount of thickness is crumbly. I burn to storage and burn very hot but I have never gotten that odor from it. I do agree, however that storage is worth a try since it has so many other merits it would.'t be a waste of money.
I would also stop burning any of the pallet blocks that are compressed wood.
I believe storage is the best answer long term. Many air reciever tanks are available on long island.
As well as or before adding storage. I would recomend checking draft in the pipe as is while burning full bore. I would also check the temperature of the chimney pipe/exhaust in several places(bottom/middle/top). I believe you will find that it is not sufficent @ only 12' in length. thus not allowing air to be introduced into the burn chamber.
Then add two sections of 3' pipe with no cap and repeat test. If test is better add cap and retest.
My 2 cents for cheap solution.
Is chimney length really that big a factor though in getting enough air for proper burn in the burn chamber with a unit with such a forceful forced draft as the Gun?
You can do a short horizontal pipe out of a Garn & I've never read about these kinds of issues with those.
Smoke the bugger out
Does anybody really believe that burning at nite will change things?
I think this neighbor got a bee in his bonnet over this boiler and no matter what he's going to find a way to complain.
Most 'nuisance' burning ordinances are written to limit the amount of 'visible smoke' or 'excessive smoke' or if they want to get really technical they limit the 'opacity level' of the smoke for x number of minutes. So burning to storage, which means very little smoke, should satisfy the local ordinances. It's doubtful that there are any laws regarding the smell of a wood burning appliance on the books. And if there aren't any all Mike has to do is comply with the rules regarding smoke output. His neighbor would be able to complain all he wants and nothing would happen.
March 28th was 50 degrees if I remember correctly so the unit was probably in idle(suffication). That would mean there was little to no call for heat. thus the fan would be off. The smoke then has to exit by natural draft if the pipe is short?
So if you cut of the oxygen then the fire will scavange anywhere it can find it. most likely pulling the smoke back through the chimney. I am willing to bet that you could put your hand on the chimney as exhaust burns cool with less oxygen.
I would recomend reading the link from Woodstock about the chimney. It is right on the money. The chimney on all wood burning appliances is critical to the design efficiency of the appliance. I could not find a manual online for the woodgun to see what they recomend for chimney but I know from experience that interior is better than exterior for draft. If i take a great stove with a 8" flue and restrict to 6" chimney I can line the chimney with creosote and reduce the output of the stove considerably.
Of course you have the ethical design considerations with an install such as this one. This ethical challange is documented in the best practice method in OWB industry. It also discusses timing of refueling vaguely. I instantly thought does this mean my conveince for reloading or timing for emissions as to not be offensive.
The Garn was not designed to idle.
This boiler would be simliar if the fire where to burn out as is being suggested by adding storage.
I can not find on the wood gun site, but it appears the fan is pulling air through the firebox? Is there a draft inducing fan on the exhaust?
It has a large centrifugal fan within the unit that draws combustion air through the firebox and through the tubes snd sends it out thru the cyclone. You were so "matter of fact" about your fixes I would have thought you would know how the unit is designed. If you do find a schematic of the design you will probably not be so sure your changes will work and that flue temperature at different points will have little effect on the operation. I can tell you are very knowledgeable on most systems but the Wood Gun is a totally different beast.
I am still thinking it needs a natural draft to aid this blower fan. even with a fan blowing, without a draft it is like closing the window. The advertisement discusses the low flue temp. I was curious about this because low flue temp and idling is not usually good in my experience.
I would love to disassemble a unit and see how it looks after a few seasons. I do not have one.
A picture of the inside of the "swirl chamber" would be interesting. Seems to me this would be where the majority of the exhaust cooling takes place and the air flow is redirected to the exhaust cyclone ash collector(which i believe is not powered by electric?). I am curious if the swirl chamber is clear of creosote?
Question: the unit shuts down the air intake and fan when not calling for heat by the damper in the rear? Then where does the smoke/gas go? can it escape naturally or does it sit in the main chamber and find its way to the swirl chamber?
the hot fire will not want to shut down so it will burn and scavange it until it is out. where will the biproduct of combustion go if the fan needs to be on for draft?
The pictures show creosote on the cap but the explanation describes a clean pipe with just ash or flakey residue. this again makes me think of a draft problem as the cap would then be very cool thus allowing creosote to stick.
The length of chimney verses draft is a matter of fact. What works with this unit is the question I posed earlier dealer may have information or the manual.
Adding lengths to chimney will certainly be the cheapest solution and easy to try. I do not run a cap on insulated class A pipe as they usually clog. I have fabricated a flat cover and attached about 1' higher then end off pipe for rain.
Just my experience.
The swirl chamber is easy to access. Just unscrew the nuts securing the fan and motor assembly. I always peeked in there every year during the final cleaning and found it surprisingly clean. I believe the swirl chamber and the steel tubes despite a small amount of ash laying in the bottom stayed clean as a result of the scrubbing by the rapid movement of ash laden gas that actually "scrubs" the walls. (and wears the refractory) I would say it's a pretty wild environment.
Wnen the unit goes into idle it closes up quite tightly assuming the door gaskets are in good shape so It takes quite a while for the gasses to dissipate out the stack.
I believe adding lengths to the stack will help but only to bring the exhaust higher in the air, hoping the odor will clear the neighbor's nose. Not all caps plug. I just went through 6 months of burning and the cap on my stack is clear and a finish that looks like chrome plating after it is removed form the plating reactor which is a shiny transparent charcoal gray.
Thanks for the clarification.
We have no rules like that here as evidenced by the number of "old skool" Wood Doctors that regularly idle all day belching TONS of smoke. In one sense Im glad we don't have rules and in another, when I have do drive through the cloud, I kinda wish we did
I do not yet have the 8 years with the WG that Fred has, yet, but I do not find this odor at a "full burn". It does seem to be a start up/shut down (mostly start up) thing in my use. My quess that at startup, the reintroduction of air along with the fan draft pulling, without the aid of the fire roaring yet, throws out these unburnt gasses that stink. As Mike, and Fred kinda mentioned, everything below the firebox is only dusty/ash(y) with no creosote at all. My question is can hot air (smoke/fumes) ever fall or not rise? With a creosote free enviroment at a level in the WG that is at or equal level to allow these fumes to rise through the cyclone? In other words the firebox/creosote is about 2' above the exit elevation @ the cyclone.
Somebody from Woodgun should chime in here. Really.
The pool is on my property and the fence is just around the pool.
I was try to show the stack in relation to the rest of the house and how dumb it would look if I raised it anymore than it already is.
The complaining neighbor is across the street behind the trees. (the last picture)