Enviro Mini simply does not auger well for me

[Ill Wind]

I am new to both pellet stoves and this forum, so please forgive my rank ignorance. I have inherited a Sherwood Industries Enviro Mini "A" pellet stove with the 900sq/ft home we recently purchased. The stove has been thoroughly cleaned by myself, right down to the motors etc and appears to function moderately well at medium to high settings. However, at low and medium low settings the unit appears to be have a problem.

The auger is erratic in it's delivery: namely it will "cycle" sometimes as many as 4 or 5 times where no pellets at all are deposited in the burn-pot -- maybe a few chunks and some dust at best -- then it will dump the entire amount that should have been slowly metered out in 1 or 2 dumps, then back to nothing at all for another 3 to 5 cycles, sometimes more. Rinse and repeat. The fire burns right down to small embers while the auger is firing blanks, then it burns very high after the mother-load gets dumped. I have vacuumed and cleaned all traces of pellets from the base of the auger inside the hopper, but have not removed the cover as it is still factory sealed. This condition has occurred using different manufacturers of both fir and hardwood pellets, so it appears the pellets themselves are not at issue here? Is it possible the auger itself is damaged? I can see it turning with each cycle, so the gears and motor seem OK. At higher settings it continues to do do this, but because the cycles are closer together the issue does not affect heat generation quite as much. It simply seems to be rather inefficient to have the fire surging so much.

Would removing the auger cover be a good idea? If yes, what sort of gap should there be between the auger and it's cover? And I assume a moderately heat-resistant RTV silicone will suffice for resealing the cover? I actually have a tube of "copper" rtv which is rated to 600 degrees I believe.

Thanks for your kind attention

 

[Bioburner]

You may have an obstruction in the auger flight. I run into this issue more dealing with use of biofuels, cob, vermin pieces too. Others have found toys, nails, string, bag pieces etc., .etc. Plant worker lost a finger.
So yes you may have to remove to properly figure this out. If you do I would get some graphite paint for it and that can help slip things along in the future.
Some augers are just not properly fed by the bin, poor designs.
Good luck and Welcome

 

[bubble]

I installed my Mini "A" last winter, been thru 1 heating season with it. It's my first pellet stove experience.

My new stove does the same thing. First question to you...does the stove burn WITHOUT EXTINGUISHING on low settings? If so, you just live with it. If you find yourself coming home to a cold house, that calls for attention.

My Mini is in a 250 sq. ft porch that is well insulated. First winter we were getting BAKED out of our gourds, WAY too hot. Having learned to set all controls to reliably burn on low is the secret. Setting then NOT TOUCHING ANY MORE the left side damper is the key, then ADJUST the pellet feed trimmer & combustion air trimmer as current conditions & pellet specifics demand. My stove DOES burn a tad inefficiently as a result of my small porch/low burn rate setup, but I can live with the minimal hassle of additional maintenance (dirty glass etc).

I've also tried CHEAPER Agway pellets, for their LOWER BTU's, to aid my stove so it will burn cooler. Perhaps try the "JUNK" pellets. My mini seems to not care what I put in it, but it DOES burn less hot with the cheapies.

 

[hearthtools]

 

[hearthtools]

I just services one last week and found all this under the cover

w

 

[bubble]

WOW...

Those pics look like someone used damp pellets that solidified when they dried from the stove's heat. Did you find the auger motor assy. fried? What symptom did the owner report?

 

[Pat Shuff]

Our '06 Mini used since new as primary heat routinely extinguishes after 2 to 12 hrs or more on the lowest #1 heat setting due to flare ups then erratic auger feed as you say. Seems a feature not a bug. Has never extinguished on a higher setting. Auger trim can be increased which results in a higher heat output without extinguishing (too high for typical OR coast temps) basically the same pellet input as #2 heat output and pellet usage.
We like the stove despite this inconvenience, it suits our needs. Always used manual control not thermostat.

https://www.hearth.com/talk/threads/enviro-mini-auger.40617/#post-514381

 

[Ill Wind]

Some fascinating replies folks, thanks. I am particularly struck by the images of severely impacted augers and my best guess (as a veritable infant with pellet stoves) is I may have something similar going on. I also considered the notion that the Mini is prone to this sort of inefficient burn when set on low, but the original installer/supplier vehemently disagrees with that hypothesis. He correctly states that the stove should work to spec on all heat settings and if it is suffering at low then there is something wrong with it.

Of course they are very happy to remove the stove and do a complete service on it and return it when completed, but the cost for that work is close to half of a new, bigger stove. This appliance should heat a 900sq/ft home well, but in reality it is having to work much harder than I might have expected. It cannot keep up, even on high, when the temps dip below -20 and I have to turn on the electrics, which is akin to unconditional surrender. Aquiring a larger version is well past the planning stages now and the hunt for the right fit begins in earnest in the spring.

I am going to remove the auger flight (thanks for the correct nomenclature) and see what I find. The graphite lube idea might be all it needs once the assy has been cleaned and checked. As for the motors themselves, is it wise to lubricate the bushings on those, or better to simply keep dirt and dust away. The shaft bushings appear to be oil impregnated brass bushings and they typically do not like extra lube.

Many thansk for the considerate tips. I shall report my findings.

 

[johneh]

You seem to be asking a lot from a stove that is rated at
30 thousand btus . Unless your 900 sq. ft. home is very well insulated
and dam near air tight at -20 a stove (space heater) rated at 45 thousand btu
would have to work hard to keep the space warm. I have know idea
what the construction of your home is , All Enviro stoves work the same
on low the flame cycles up and down it is the nature of the beast.
(Pellet drop type stoves) and has no effect on whether it is an inefficient
burn or not . to me an inefficient burn is one where all the pellets do not burn
Hope you find a stove that works the way you feel it should .
My Enviro stove rated at 45 thousand btu will keep my summer kitchen ( R12 walls
R40 roof ,R6 floor built 1926 not air tight ) warm at -20 300 Sq. Ft. but will do
very little for the rest of the house but I bought it as a space heater for that room
and did not expect any more out of it. It will in shoulder season heat the rest of the house .
Which is a plus as far as I am concerned .

 

[Ill Wind]

I can only rely on my knowledge of thermodynamics and say with some confidence that a surging flame is not as efficient as a steady one, at least in these conditions. QED. I am not talking about the flame going from 2 inches to 10, rather it goes from ziltch (just a few coals) to smoky flames all the way above the glass. On LOW! I'm sorry, but this surging business is decidedly inefficient and wasteful. This mini is rated to 1200sq/ft and the insulation etc at this house is good but not great. Even the highly experienced vendor says It should be just fine for this house. They did the install for the previous owner btw, I did not buy it and probably wont buy another like it. The temp differences and fuel usage between the bottom 2 settings is too far apart, even with adjusting the fan and feed trim. (Feed trim is set to max on low, then turned down to default 4 at all other settings. Helps a little) Setting the choke is darned near impossible with such extremes in flame characteristics. But I will soldier on until summer when I replace it. Here's hoping the graphite inside the flight will help a little.

 

[pete7713]

Something is wrong with your stove I have a mini, I set the damper after letting the stove burn on high for about 15 minutes. When I put it on low the flame varies from about 2 to 4 inches does not go out and I can run it all night like that. I generally run it on 2 at night and 3 or 4 during the day. I'm heating 1200 sq ft with no problem, than again it rarely gets below the twenties here. Other than the damper I haven't touched the other controls.

 

[hearthtools]

The reason for the trim setting is to set the feed on time longer
Reason
Pellets will come in different lengths. Shorter pellets fill the auger tube more densely and more consistent rate of feed
Longer pellets have more void space in the auger tube and will drop at a less consistent rate. What happens on all stoves is if the feed on time is only 2 to 3 seconds a few pellets will drop with a feed cycle then none then a few then none and sometimes a whole bunch will come out and smother the fire. Setting the trim helps this for the low or thermostat setting. You are really not using more pellets because of the density of material in the auger tube

 

[hockeypuck]

I have a Mina a and the lowest setting can be problematic. Tried with two different types of pellets (ambiance and cubex) and while the cubex has faired better, the burn pot will still fill up after a few hours of low setting use. The Ambiance were worse... low quality pellet and longer. I just do not use the low setting.. which stinks because I would like to use a thermostat and run on lo when the thermo is statisfied, but I guess it is not meant to be. I just run it at 3 or 4 most of the time.

 

[bubble]

I have a Mina a and the lowest setting can be problematic. Tried with two different types of pellets (ambiance and cubex) and while the cubex has faired better, the burn pot will still fill up after a few hours of low setting use. The Ambiance were worse... low quality pellet and longer. I just do not use the low setting.. which stinks because I would like to use a thermostat and run on lo when the thermo is statisfied, but I guess it is not meant to be. I just run it at 3 or 4 most of the time.

I'm not sure why you can't still use a stat. I keep my Mini A on heat setting 2, controlled by my smart stat. When the stat is satisfied, the stove just idles on low.

 

[hockeypuck]

Can't idol on low...I think I misspoke above. I can not run on low...only second lowest setting

Sent from my VS986 using Tapatalk

 

[Deromax]

My stove is doing this and I think it's completely normal. As long as the fire doesn't go out, who cares. Pellets have various sizes and are randomely arranged in the hopper. This kind of fuel cannot be precisely metered on a second-by-second basis by an auger, unlike oil or gas which are flowing smoothly and constantly. If the average over a minute or so is producing constant heat, there is no problem.

 

[Ill Wind]

Sorry for the delay, life etc routinely interferes with my best laid plans... Thank you very much for the thoughtful replies, they are most helpful. One of the biggest problems I am having with this stove is my own inexperience. It is difficult to even ask appropriate questions when one's understanding is so limited, but I am getting up to speed very quickly -- I hope. However all that said I am beginning to suspect there are indeed a few issues with my stove, mostly due to a lack of proper maintenance by the previous owner. Still, the explanation given above by Hearthtools is what I suspect lays at the root of my issues with low settings and I have been somewhat able to adjust/trim my way around them. Nevertheless a complete service by a qualified technician is a must at this point. The stove has developed a shrill, squealing noise that if left unaddressed leads to broken dishes, peeled paint and several days in intensive psychotherapy. I will report back any details. I decided to put my hands in my pockets and keep them away from this stove until I am much more knowledgeable! Probably saved myself a fortune...

 

[bubble]

There's nothing that a pro will do that you can't do yourself. You would need the manual though. Routine maintenance is a sequence of events described there. On a scale of 1 to 10, it's about a 5 in difficulty. Even easier for the mechanically inclined. Good luck, and WATCH the pro do his thing, so you will only have him do it ONCE!

 

[Ill Wind]

That's my thinking: paying a pro not only gets the stove up to snuff right smartly, it allows me to absorb a great deal of knowledge too. I do have all the manuals and have even removed some covers and stared into it's wretched black guts. I reckon I could probably wing it, but with the weather as cold as it is and my skills with this stove as poor, it is simply wise to bring in the big guns this time. It's got to be close to running well enough so the cost should be reasonable. My hopes are pinned on the irritating racket being dirty fan blades causing a sympathetic oscillation in a shield or something. It's that kind of noise, rather than a typical bearing sound. It's bloody awful and of course only happens on the lower settings. I do not miss bucking, splitting and endlessly stacking of wood, but I do miss the simplicity...

 

[Pat Shuff]

The reason for the trim setting is to set the feed on time longer
Reason
Pellets will come in different lengths. Shorter pellets fill the auger tube more densely and more consistent rate of feed
Longer pellets have more void space in the auger tube and will drop at a less consistent rate. What happens on all stoves is if the feed on time is only 2 to 3 seconds a few pellets will drop with a feed cycle then none then a few then none and sometimes a whole bunch will come out and smother the fire. Setting the trim helps this for the low or thermostat setting. You are really not using more pellets because of the density of material in the auger tube

Bought a half ton of doug fir Blazer pellets that became available locally, shorter length than Golden Fire without the longs, more even auger feed, fewer flare ups and die downs, the frequent extinguishings on the lowest Mini heat setting have virtually stopped. The Blazers are hot and clean.

 

[bubble]

I've come to several conclusions about heating with my Mini A:

1) Basic reliable operation is HIGHLY susceptible to the natural variations of the pellets used, especially on this stove's lowest setting.
2) Same can be said about the FLUE, and the presence of, or lack of, an OAK.
3) Reliable combustion on low burn CAN be achieved; closing the slide damper a little at a time can help locate the SWEET SPOT to make this possible. This SWEET SPOT seems fairly precise to me, in damper slide travel. This spot can change with different pellets.
4) Most pellet brands have a LOT of variability in quality, even between different bags from the same pallet. Higher quality pellets (re: more expensive) are more consistent in quality. The COUNTRY BOY pellets I've used are made by a hardwood flooring manufacturer, so their all oak pellets are made from the residuals from their oak flooring factory. These are very consistent pellets.
5) For those of us with OAKs, the outdoor air properties affect combustion significantly; specifically temperature/dampness/wind.

These things can all be gleaned by anyone using any pellet stove but the learning curve can be greatly shortened by searching this forum. Some fantastic people have posted great info recently, and over the years, and I say THANK YOU to all, especially those of you who install & maintain these things for a living.

 

[westgateblvd]

I have a Enviro Evolution. This is my second one. Saw dust is the worst thing to have. We get some pretty bad pellets here. You have to drop the bags a few times to get the dust to the bottom of the bag. Then pour it in until you start seeing the dust, then stop.

 

[Ill Wind]

I am sorry for being so slow to respond to all these terrific comments. I have indeed discovered there are myriad variables that affect performance and I have no doubt each stove also has it's own quirks to consider. But to catch up a bit:

I had a certified tech attend the house and all he did was check the chimney and stove etc for dangerous conditions, and having satisfied it's all to spec, he encouraged me to pull the side-panels off and get stuck in. I sent him away with a decent tip and got to work. I cleaned away a lot of hair, dust etc and thoroughly vacuumed everything, then slapped the covers on and away she went. The noise still does reoccur if I use the variety of fir pellets available locally, but if I mix it with hardwood it is much less frequent and tolerable. But I tend to stick with the hardwood because it burns longer and hotter in my stove. I also prefer the ash I get from hardwood which is much less "greasy". I use a meat cooking probe clamped inside one of the air tubes to gauge the temps and I get ~20 to 40°F more actual heat output from the hardwood I buy. Trim settings are the equivalent of using a hammer to swat a fly so I tend to leave the trim alone mostly and go with what the manual recommends, unless I want to really dial the stove down low. The fresh-air damper appears to be the best way to fine tune this stove. I am thinking even the weather affects low setting performance and with the temp probe I can dial it in very nicely now.