fire box half full of coals light blue large lower flame

[Rugar]

Eko 25 burning very dry hedge (Osage orange). Fire box becomes half full of coals and flame in lower end is a large light cloud like blue flame. When idling some smoke continues to roll out of flue. What adjustments should I make. Currently fan shroud is half closed and fan speed is 50-60%

 

[jebatty]

My take is that when you have a light blue cloud-type "flame" that at the extreme becomes invisible to the eye but roaring to the ear, you are oxidizing CO and/or hydrogen without other components. CO oxidizes around 1100F, with exhaust of CO2 and water, and hydrogen oxidizes at about 1400F with exhaust of water. I'm no chemist, but I think the reactions may be CO + H2O -> CO2 + H2, and then H2 + O -> H20, or perhaps in the reverse order.

 

[ihookem]

Jebbatty, ya sure sound like a chemist.I thought it was burning good with a light blue flame. Sounds good to me.

 

[Duetech]

Blue is good with a gasifier but my understanding is there should be more of a torch (propane type) than a soft blue cloud. If the cloud is only present for a short time during idling that's par as the pressures in the gasification chamber are forcing the volatiles out but the cloud should disperse seconds after opening the lower combustion door. If the cloud is present during actual operation It sounds like you need a little more primary air pressure.
A chamber half full of coals is not too uncommon but smoke from coals is not really desirable and may hint to a bypass valve gasket leak. If you have a bypass gasket leak you should be able to to find soot/creosote build up in the chimney and will probably experience extended or long idle periods (assuming you are not using storage).
I have never burned hedge but it is possible that the size of your splits is a bit too small. The btu storage in hedge is some of the best to be had and if the wood is very dry and split too small your gasification chamber may be working too well. Coupled with the draft of your chimney during idling you may be pulling the fire out of the gasification chamber and keeping the draft process going (blue cloud) but not pulling enough secondary air for full fledged torching. In that case you may want to look at going to a larger split and/or actually reducing the air on your primaries. In a "lighter sense"... what a wonderful problem to have.

 

[jebatty]

A little disagreement here, and maybe a super pyro can sort this out. I think the orange is evidence of combustibles others than CO and H2, as both of these oxidize near color-less, hydrogen especially. No disagreement that improper primary air also may affect color at various stages of the burn, although oxidation from "pure" coals, all carbon, is a different scenario - only C, H2O and O2 involved.

 

[taxidermist]

Eko 25 burning very dry hedge (Osage orange). Fire box becomes half full of coals and flame in lower end is a large light cloud like blue flame. When idling some smoke continues to roll out of flue. What adjustments should I make. Currently fan shroud is half closed and fan speed is 50-60%

No sure what your looking for? You will always get smoke at a idle. If your looking to get a torch like roar turn your fan speed up. Low speed = lazy cloud flame.

Rob

 

[Rugar]

Im burning 4-8 inch unsplit logs however some of the trees were cut 8 years ago and some were 40 years ago. It's still reltivly solid but way dry and dulls saw quickly. Do you suppose adding some 35 percent moisture oak would help in combustion. currently im not getting extended burn times like i would expect. It seems as though Im loosing a lot of energy somewhere. Oh what a time I wish I had storage set up.

 

[stee6043]

Can you tell us more about your heat load? What kind of burn times are you getting and what were you expecting? If your boiler is not idling a whole lot a nearly full fire box of good, dry wood should only last 4 hours or so. Maybe a little longer. If you are idling 50% of the time than perhaps you should be getting 6-8 hour burn times. I really don't know how long a full load should last without storage. I run black cherry at less than 20% moisture and it typically lasts me 3 hours when I fill to the bottom of the door opening (max) with zero idling and plenty of coals left to reload without issue.

As far as I know a blue flame is great. If you have some time read the "fine tuning EKO" sticky in the boiler room. There is a fair amount of discussion on air settings and flame type/color/duration. Very good info...

Last thought - 8" splits are too big, in my opinion. Especially if they are unsplit. They will season more slowly and you may or may not experience a fair amount of bridging with splits that size. I'd say 90% of my splits are 4" max. Burns much, much better than my first year burning 6" and more on occasion. You might also be surprised at how little a non-split piece of wood will season. 8 years might be as good as 8 weeks depending on the conditions and the wood type...