Eko 40 Settings Diary

[Jayf19]

I've been breaking in my Eko 40 for the past week and a half and I thought I'd record my settings evolution somewhere. Right now my goal is to at least be able to burn a full load of wood without the fire/gasification choking out... I'm, not heating the house just yet as I'm waiting on the foam guy to come spray my tanks this weekend. I just don't want my lines freezing!

Yesterday evening, I started the fire at 7pm following Nofossil's To Build a Fire, Version 17. To anyone having a rough time starting a fire from scratch, I suggest reading it (https://www.hearth.com/talk/threads/to-build-a-fire-version-17.119656/). The initial startup was as easy as decribed in NoFo's thread, not even 2 minutes after lighting, I closed both door and let the heat build up for a few minutes. I added a bit of wood; box was about 1/3 full at hat point. Considering I'm having a tough time creating a nice bed of coals and keeping the fire lit, I went inside for dinner with the damper open.

45 minutes later, I came back in the garage to find a decent bed of coals and a boiler temp to roughly 150F and so I filled the box to 3/4. I waited about 10 more minutes before closing the damper to let the wood heat up a bit. Very small blue flame at that point. Went back inside for about 1 hour and when I came back my water temps were at 70, a nice bridge had formed and no gasification was occurring... I broke the bridge, filled the box for the night and closed the damper. Full roaring gasification instantly. It lasted for about five minutes before starting to choke.

Woke up this morning with a nice bridge, again, as usual, with 3/4 of the wood remaining in the box. Rinse and repeat, I started the fire with no problems, when I left, I was in full gasification for less than a minute after which the blue flame got smaller and smaller to the point it died. I'm expecting the same results by the time I come back home tonight, with about 3/4 of the box still there. If that's the case, chances are my lines will have frozen.

Information :

Wood type : 15-30 % dry white pine and larch (I'll be switching to 100 % larch (dry) in the upcoming weeks, just waiting for my supplier to be able to get to his wood land)
Blower opening : 10 %
Blower speed : 30 %
Primary opening : 9 mm
Secondary turns : 5
Wood size : No more than 4 inches wide per split, 12 inches long
Secondary tubes are cleaned and holes are aligned adequately

 

[huffdawg]

I run my fan speed @ 70% or 80% when starting then after 15 mins and the fire is gassing good I turn it down to 60 or 50 depending on flue temp.
Blower opening around half. splits small and then if I have any big splits I'll load them in at the top.
Open your blower more and turn your fan speed up.

Huff

 

[Jayf19]

I run my fan speed @ 70% or 80% when starting then after 15 mins and the fire is gassing good I turn it down to 60 or 50 depending on flue temp.
Blower opening around half. splits small and then if I have any big splits I'll load them in at the top.
Open your blower more and turn your fan speed up.

Huff

Tried that last week; so far, over the course of last week, I have tried going progressively from 12mm openings down to 7 mm all at fast speed, I noticed that I went from a strong orange flame (no blue) with lots of pockets/bridging and coals falling down the nozzle to a choked out fire that still had pockets and bridging. I came to the conclusion that since I'm still getting pockets no matter what the primary feeding is set to, the problem must be with the air velocity, and not with the oxygen mix between the chambers. Also came to the conclusion that since my primary chamber was choking out, it could be because it was underoxygenated afterall. With that in mind, I've started working my way back up from 7mm using a slower blower feed and speed - to no avail so far. Maybe I've cut back too much on the fan power, though, I guess that's what I'll try tonight.

 

[Jayf19]

Just got a call, fire died, temperature is down to 136F.

 

[maple1]

Might sound like a 'same old story' type of comment - but maybe your wood is on the damp side? If I read right above - it's between 15% & 30%? I know I would expect pretty disappointing performance if I tried to burn anything around or over 25% in mine - and also if those are measured with a meter, the accuracy on those gets worse the higher the readings, so a measured 30 might actually be even wetter.

 

[Jayf19]

Might sound like a 'same old story' type of comment - but maybe your wood is on the damp side? If I read right above - it's between 15% & 30%? I know I would expect pretty disappointing performance if I tried to burn anything around or over 25% in mine - and also if those are measured with a meter, the accuracy on those gets worse the higher the readings, so a measured 30 might actually be even wetter.

That's what I fear...

I'll make a quick trip home at noon to boost the blower velocity and open up the primary chamber to let more air in. I'll get the burn settled first, once that's secured I'll try to tweak the flame.

 

[maple1]

I've found that aside from giving a poor overall burn, wet wood will also bridge much easier.

 

[Jayf19]

I've found that aside from giving a poor overall burn, wet wood will also bridge much easier.

I have some nice pieces here and there, but I do realize I have some pieces that aren't as good. Although I wouldn't say they are wet, they are definitely not optimal. Anyways, when I got home, water was down to 100F, as I was pulling the cover down, I heard the fire start up on it's own due to the injection of oxygen from the openings. I opened the primary chamber back to 12 mm, blower 50 % open and velocity back at 70 %. I broke the bridge, brought the temp back to 160F, added a few pieces on top of everything and closed the latch. Fingers crossed that I was able to pull some heat off by the time I get back home tonight!

 

[Fred61]

Bridging occurs when wood doesn't combust rapidly enough to keep the area over the nozzle supplied with charred chunks. If it takes extra time for the logs on top to first get the water boiled off before they start charring then bridging will happen because the charcoal over the nozzle has burned away while waiting for more to drop. A little too high in moisture and you will be knocking down bridges all winter.

 

[hartkem]

I agree that your wood is likely to wet. I had a few issues with bridging the first year I had my eko because my wood was only dried about 6 months during the summer. Now my wood is a minimum of I year old and I rarely have bridging issues. I burn my eko 40 at 70% fan speed with shutter fully open. I can't see how a fire could go out in the EKO with it running unless the wood is way to wet.

 

[Jayf19]

I agree that your wood is likely to wet. I had a few issues with bridging the first year I had my eko because my wood was only dried about 6 months during the summer. Now my wood is a minimum of I year old and I rarely have bridging issues. I burn my eko 40 at 70% fan speed with shutter fully open. I can't see how a fire could go out in the EKO with it running unless the wood is way to wet.

I agree that my wood is most likely borderline too wet for gasification, but definitely not for burning. I think what happened is that I was choking it out by not allowing enough oxygen in the primaries.

In any case, I changed my settings to the following yesterday :

Blower opening : 10 % > up to 15 %
Blower speed : 30 % > up to 50 %
Primary opening : 9 mm > up to 12 mm
Secondary turns : 5

Although I have lost any hope of attaining gasification at any time during the whole burn with these settings, I can't even get orange flames down the nozzle, I at least have been able to burn 3 full loads without choking the fire down.

 

[huffdawg]

With wet wood I would open blower opening all the way and run the fan as high as it takes to get gasification.

 

[mr.fixit]

I agree with huff.
Changing the shutter opening from 10% to 15% will probably make little to no difference.
Open it up all the way and adjust the speed via the controller after you get it going good.
After you get a partial load gassing good,load it fully to the top,the weight of the wood on top keeps pushing down and self feeds.
You have to put the wood in fairly straight,not all tangled up and crooked.
In the end though firewood isn't a perfect fuel. It's not going to burn perfect every time.

 

[Jayf19]

Worth trying - I'll give it a shot tonight while I daisy chain my thermometers.

 

[Coal Reaper]

anything will burn if you get it hot enough and has an ample supply of air.
dry wood doesnt bridge, unless your splits are HUGE or not long enough to cover the nozzle (i.e. primary are can get to the secondary chambers without flowing over wood).

 

[huffdawg]

If the wood is to long it will bridge also. The splits get stuck at an angle in the burn chamber and won't drop down

 

[Coal Reaper]

never had that happen. most of my wood is 19-21" in my 21.5" deep firebox. longer splits i will put in diagonal with no ill effect.

 

[Jayf19]

When I got home for lunch yesterday, the fire had died again (lack of air). I followed what you guys suggested and so far so good. I just can't get the water temp high enough (167F), but at least I'm keeping my tanks warm and my lines aren't freezing. I should be getting my insulation done this weekend.

Blower opening : 15 % > up to 100%
Blower speed : 30 % > up to 70%
Primary opening : 12mm
Secondary turns : 5

Before going to bed yesterday, as tempertatures we're supposed to drop to -22, I crammed big splits on top of everything. This morning, there was nothing left in the fire box.

I did get some temporary gasification, but most of the time the Eko is mostly running like regular OWB at the moment.

 

[maple1]

Better keep an eye out for creosote buildup in the tubes & turbs & everything else - sounds like it's not getting all the nasties burned. You can also work at improving things as the winter progresses by re-splitting your wood quite small, stacking as much as you can loosely in as warm a place as you can get it, and running a box fan on low speed into that pile (or away from it) during waking hours. You can get a lot of moisture out doing that in just a couple or three weeks depending on the space you have to do it in - you'd likely have to work at it all winter off & on, rotating the wood through & around. A small electric splitter is just the ticket for that. It's more overall work, but you should see a huge improvement if you can get your wood drier. Would be one of those cases where you say man that was a lot of work but I'm some glad I did it.

 

[Jayf19]

Thanks Maple

Kind of what I'm doing right now, only problem is that my tanks aren't insulated, so the heat load is ridiculously high due to the standby losses. I split wood (manually) when I wake up, when I get back from work and after dinner before going to bed! Problem is that I can't produce fast enough for the boiler

It should settle down next week once I spray foam the tanks and start doing the cellulose box.

 

[Coal Reaper]

any idea what your stack temps are?

 

[Jayf19]

any idea what your stack temps are?

I can't bring them above 110 as the with outside temperature is too wide at the moment, and that's just one of the tanks. I reduced the outgoing and incoming flows from the second tank for now since I couldn't bring both of them above 80. I am literally heating the whole neighborhood

 

[maple1]

Think he means your exhaust gas temp. Flue temp.

 

[Jayf19]

Good point; I don't have a thermometer to capture the flue temp yet, that was next on my shopping list.

 

[rkusek]

Just a few questions. What is your pump launch temp and pump hysteresis set at? Mine is 165 and 5. 170 might be even better. The factory default is way to low, around 150 I think. Gasification seems much easier at the higher temps