Tweaking EKO efficiency

[Nofossil]

I'm back at it again, with more data on EKO efficiency. This time, I tried shutting down the fan inlet shutter a bit more. My analysis looks at heat that was delivered to the baseboards, storage, and DHW tank. There's additional heat that gets into the house directly from the boiler and from all the plumbing. That heat is not measured or included in my calculations.

Summary of the burn:

- Built fire at 3:20 in the afternoon
- Added wood at 4:40. Pretty full load as I was going out for the evening.
- Returned at 11:00. Still enough coals to just add wood and let it run.

- Between 3:20 and 11:00, burned 84 pounds of pretty dry wood - 15% moisture content.
- Average output during that time was about 53,000 BTU/hr.
- About 66% of the theoretical heat available in the wood was delivered into the heat loads.

This is my best measured efficiency so far. I think restricting the fan helps a bit - earlier runs were in the low 60s.

 

[markpee]

Genius - I love your analysis. Today I'm going to measure my baseboard and try to do some figuring. Yesterday, for some reason my "fuel" indicator was on, but my boiler temp was 181 degres and circulating. I had about 3/4 load of wood left. This got me thinking. So last night I shut my temp down to 175 - which I was able to get to fast to see if pewrhaps the boiler would climb a little higher, and hence save some wood. I guess my theory is wrong, as the house was freezing this morning - the boiler was at 93 and I had a lot of wood left. I think idling killed the burn and I therefore had none. So today I'm back to 190 which seems to run the house pretty well. I also am playing with an idea whereby I shut the zone circulators down completely until the EKO gets up to 190 or so - I then turn the house circs on, as this seems to tolerate better, rather than trying to heat the delivery lines and zones all together. I think of it as balancing - in fact, shutting zones down and bringing them on one at a time would probably even be better. Sorry to rant.

Mark

 

[Duetech]

Thanks Nofossil,
I don't have the instrumentation for the hard data. But I have found that tailoring back the air (as per EKO manual) gave me a longer burn. With no storage that is important. Hopefully next spring I will get my storage set up built. Solid info like what you have supplied here will make it a better system than I had anticipated.

 

[fishon]

Hey Cave, what do you have your settings on? I too have an EKO with no storage and I would like to get the longest burn time possible. Thanks.

 

[Nofossil]

Thanks for the kind words. Spreading information is what I'm all about here, and I've picked up as much as I've provided.

Couple of points of interest: I do some load balancing. If you look at the heavy horizontal lines at the bottom of the graph, those show zone valve states among other things. For instance, the green line is the recirculation valve that allows water to circulate directly back to the inlet. It's used to help the boiler get up to temp, and as input temperature protection. Early in the fire, heat is going to some high priority loads - superheating the DHW and heating the hot tub. I don't put much into storage until those zones are satisfied.

You can also see 4 idling cycles near the middle of the chart. This happens when the tank top gets hot enough so that it can't transfer enough heat into storage. The boiler outlet rises to the point where the EKO controller initiates an idling cycle. As the combustion temperature drops, the boiler output drops enough so that idling is not required.

 

[markpee]

It would be great to see a picture of where your fan inlet shutter is (cave or Nofossil) - anyone care to share?

 

[Nofossil]

The inlet shutter on mine is a rotating disc with cutouts, mounted on the fan. You can rotate the disc to create a larger or smaller opening. Don't have a picture, but if you pop off the green fan shroud you can't miss it.

 

[Eric Johnson]

What's the size of the opening on the fan housing now, nofo? I closed mine down to about an inch last week and I'm getting longer burns. Did you notice a drop in your exhaust temps after making the adjustment?

 

[markpee]

Okay - the opening is a "pie shape" at what point are you measuring "1 inch"?

 

[Eric Johnson]

At the widest point, i.e., the top.

 

[Nofossil]

Okay - the opening is a "pie shape" at what point are you measuring "1 inch"?

Across the points of the crust - the outer edge of the opening. It's actually 1.14", and I think an eighth of an inch makes a measurable difference.

 

[Medman]

NoFo - I got my EKO 25 fired on Sat for the first time. Once I burned off the refractory moisture, about an hour, I added about 1/4 load of mixed size splits, all 15-20% MC hard maple. I was gasifying in no time, reached 180* in about an hour, and had the loop hot about an hour after that. However, the wood did not last long. I am wondering what you have your primary air and secondary air settings at.
I am using the settings in the new manual as a guide - 10mm for primary, 3.5 turns out for secondary, half open for fan shutter. I think it could be better, and I am just curious where your settings are.

 

[sfriedri]

Okay - the opening is a "pie shape" at what point are you measuring "1 inch"?

Across the points of the crust - the outer edge of the opening. It's actually 1.14", and I think an eighth of an inch makes a measurable difference.

What fan power do you use with this much opening? Right now I'm running with the fan shutter 100% open and the fan power at 50% (RK-2001U controller) and this seems to provide a good clean burn. Anything less and I tend to get smoke, especially when starting a fresh load of wood.

 

[Eric Johnson]

Nofo and I both have the old controller, so there's no fan speed setting. Of course, nofo has some pretty fancy supplemental controls on his boiler, so maybe he is modulating the fan speed at lower temps. I actually have the new controller, just haven't hooked it up yet. I'm a little intimidated by all the setting options, but it sure sounds like you get more flexibility--and maybe better efficiency.

 

[sfriedri]

Nofo and I both have the old controller, so there's no fan speed setting. Of course, nofo has some pretty fancy supplemental controls on his boiler, so maybe he is modulating the fan speed at lower temps. I actually have the new controller, just haven't hooked it up yet. I'm a little intimidated by all the setting options, but it sure sounds like you get more flexibility--and maybe better efficiency.

Yeah, there are quite a few settings on the new controller. My EKO came with a RK-2001E controller, but it failed after about a week of operation, so they sent me the new controller as a replacement.

The main settings that I have changed to try to optimize operation are the fan speed, the "fan work time" during the pulse that occurs when the boiler idles, and the two no fuel test times. Quite a few of the settings are not relevant to my installation, since I don't have the boiler control interacting with the circulators.

 

[Nofossil]

My primary sliders are wide open, as they came from the factory. My secondaries are 4.5 turns out. As Eric mentioned, I have the old controller which doesn't allow much of any adjustments. I've taken over control of the circulator, but I'm leaving the fan to the EKO controller for the time being.

 

[Hansson]

I know that in some eko controllers there is a factory menu. Service mode.
But I think you now abot that

 

[hkobus]

I also believe that the reduced settings are extending burn time, no facts like Nofossil, but gut feel is clear. I run with dry wood at about 0.5 inch and wetter wood or cold unit at 1 inch. I found the flame much steadier and the load to last longer.
It also seems to give me less and heavier ashes.

Henk.

 

[Duetech]

Hey Cave, what do you have your settings on? I too have an EKO with no storage and I would like to get the longest burn time possible. Thanks.

My primary air settings are the only thing I have adjusted. The little louver right on the blower housing is adjusted to almost 3/8" open at the wide part of the opening. A fire built on good coals needs no tinkering. I open to about 25% on a cold fire and bump back to around 10-12% once gassification is achieved. I can actually use 5-7" splits for the longest burns by laying 3-4" splits on the coals then loading the bigger pieces on. I'm still getting 10+/- hr burns using seasoned bl walnut. I have not gone through the winter with this setting yet so I don't know how it will work. My 40 has the older controller on it the settings for it are as they were when I got it=81c max. Walnut is not the best wood but was my major wood last year. (broken link removed to http://www.chimneysweeponline.com/howood.htm)
My fire doesn't roar as much but I get a lot more blue in it so I think I'm burning cleaner in the secondary mode.

 

[leaddog]

My primary sliders are wide open, as they came from the factory. My secondaries are 4.5 turns out. As Eric mentioned, I have the old controller which doesn't allow much of any adjustments. I've taken over control of the circulator, but I'm leaving the fan to the EKO controller for the time being.

Interesting as the new instrution manual on the new horizon site has the primary shut off quite abit, depending on model. I'm wondering how much that would change your burn. By closing down the primary it would lessen the flame in the upper chamber and add a larger percentaqge of air to the secondary. You would then have to open up the fan openings more but that would raise the air pressure in the secondary and give a better mix.
When I got my 80 it had the primary shut off and I opened it up about half way and burned it that way last season. when I saw the new manual I set it up to that and I seem to get a better burn. We also set my sons 60 up that way also.
With your set up it would be interesting to see what changing the primary does.
Also on the older ekos they don't have as many screws holding the fan cover in place and Shannon had alot of air leaking around the gasket. He taped the edges and it made a HUGE difference in the burn and when it went into idle on shutting down the burn. Other wise the fire continued to suck air and burn.
leaddog

 

[Sizzler]

My primary sliders are wide open, as they came from the factory. My secondaries are 4.5 turns out. As Eric mentioned, I have the old controller which doesn't allow much of any adjustments. I've taken over control of the circulator, but I'm leaving the fan to the EKO controller for the time being.

Interesting as the new instrution manual on the new horizon site has the primary shut off quite abit, depending on model. I'm wondering how much that would change your burn. By closing down the primary it would lessen the flame in the upper chamber and add a larger percentaqge of air to the secondary. You would then have to open up the fan openings more but that would raise the air pressure in the secondary and give a better mix.
When I got my 80 it had the primary shut off and I opened it up about half way and burned it that way last season. when I saw the new manual I set it up to that and I seem to get a better burn. We also set my sons 60 up that way also.
With your set up it would be interesting to see what changing the primary does.
Also on the older ekos they don't have as many screws holding the fan cover in place and Shannon had alot of air leaking around the gasket. He taped the edges and it made a HUGE difference in the burn and when it went into idle on shutting down the burn. Other wise the fire continued to suck air and burn.
leaddog

Leaddog, What are the position of you Primary's now?? I have mine set around half open and seem to at times get excessive flame in the lower chamber. I'm thinking of closing the primary's down a bit. I run my fans right around 1 inch at the outside of the arch.

 

[leaddog]

My primary sliders are wide open, as they came from the factory. My secondaries are 4.5 turns out. As Eric mentioned, I have the old controller which doesn't allow much of any adjustments. I've taken over control of the circulator, but I'm leaving the fan to the EKO controller for the time being.

Interesting as the new instrution manual on the new horizon site has the primary shut off quite abit, depending on model. I'm wondering how much that would change your burn. By closing down the primary it would lessen the flame in the upper chamber and add a larger percentaqge of air to the secondary. You would then have to open up the fan openings more but that would raise the air pressure in the secondary and give a better mix.
When I got my 80 it had the primary shut off and I opened it up about half way and burned it that way last season. when I saw the new manual I set it up to that and I seem to get a better burn. We also set my sons 60 up that way also.
With your set up it would be interesting to see what changing the primary does.
Also on the older ekos they don't have as many screws holding the fan cover in place and Shannon had alot of air leaking around the gasket. He taped the edges and it made a HUGE difference in the burn and when it went into idle on shutting down the burn. Other wise the fire continued to suck air and burn.
leaddog

Leaddog, What are the position of you Primary's now?? I have mine set around half open and seem to at times get excessive flame in the lower chamber. I'm thinking of closing the primary's down a bit. I run my fans right around 1 inch at the outside of the arch.

I'm not sure but I think 10mm. It is set to the settings in the new instrution book on the new horizon web site. It says to run the 80 with the fan openings open and I do that when I'm running wetter wood or real small stuff but I find I keep the stake temp lower if I run about 1to 1-1/2 in most of the time. I'm still running mine alot manually as I'm just getting it changed over and I don't have my modulating valve hooked up to the controler.
leaddog

 

[rickh1001]

This is an excellent thread for us EKO owners out there. I set my EKO 60 up close to the factory with good results so far. My wood is really dry (stored in the basement near the boiler), and I have 24ft of 8" metalbestos chimney running through the house. I am using 9 mm on the primary air, 3.25 turns on the secondaries, and the fans at about 50% closure of the "pie". I have the RK-2201UA controller with the knob, so I can adjust the fan speed, as well as many other things. I have been reducing the fan speed during work times to 90%, and will explore reducing it further.

During running, I am getting intense gasification, resembling a blast furnace, which is a good thing. I am not sure if this is the most efficient setting, but it burns cleanly.

The real shortcoming of the system is I wimped out, and have only 500 gal of storage, as I didn't think I could shoehorn one of the longer 1,000 gal tanks into the basement. Next summer, I will be adding a second tank. The EKO 60 puts out a lot of heat, and it really needs more storage capacity than I have. The other deficiency I am seeing is using plenum heat exchangers. They were quick to install, but since they require fairly high water temps to be effective, I really can't run the storage down much below 140F before I get only cold air in the ducts. This system would really shine with hot water radiators or baseboards, and would do really well with radiant floor heat, where I could use the water down to 120F or less. Plus, in a power outage, I could run the circulators for hours with my new inverter and battery backup, where I can't run the plenum fans with batteries. I am hoping to add more massive cast iron baseboard radiators to replace the plenum HX's in the various zones over the winter, rather than fin tube baseboards. They are expensive though, but would be much more compatible with this system. I keep looking for older conventional radiators, but everyone is on to them, and used ones are not cheap either.

The basic EKO system itself is working beautifully though. I am going to keep reducing the air until I start to see it smoke, but the factory settings mentioned above seem pretty close, and seem to be working well.

 

[Eric Johnson]

Actually, there seem to be quite a few old cast iron radiators around upstate NY, at least where I'm at. Go to a plumbing/heating supply house and ask. They usually know where they can be found. Or check Craig's List or the local classifieds. They generally run about $100 each. Make sure that you get rads that will work with hot water system. There are more steam rads out there, and some are steam-only, although many can go either way. Also, I've found that the taller (bigger) ones are easier to find. Apparently everyone these days wants the short ones that will fit under a window. They tend to be more expensive if you can find them.

 

[markpee]

This is an excellent thread for us EKO owners out there. I set my EKO 60 up close to the factory with good results so far. My wood is really dry (stored in the basement near the boiler), and I have 24ft of 8" metalbestos chimney running through the house. I am using 9 mm on the primary air, 3.25 turns on the secondaries, and the fans at about 50% closure of the "pie". I have the RK-2201UA controller with the knob, so I can adjust the fan speed, as well as many other things. I have been reducing the fan speed during work times to 90%, and will explore reducing it further.

During running, I am getting intense gasification, resembling a blast furnace, which is a good thing. I am not sure if this is the most efficient setting, but it burns cleanly.

That's interesting - you think there is a better burn at 90% - I'll have to try that when I get home from work. I'm wondering if this helps the wood last longer?