6 turns out on the secondary screws this morning. We’ll see how that holds up at the 2 hour mark. I suppose as long as I’m not losing secondary burn, I can keep going. True or false?
My test is in progress this morning - boiler running with house heating system shut down. We’ll see how much heat goes into the tank in 4 hours with no load on the tank. I’m still not sure what that will tell me, but it’s doesn’t cost anything to get a bit more information.
But, in thinking about this, I’ve come to another startling realization - I may not have enough hx capacity to make use of bigger pumps. After 2 hours of burning last night, boiler outlet temp was 190 and inlet was 183.
What that tells me (I think) is that the small pumps were not big enough to move enough heat to the tank, and the hx in the tank were not being used to capacity. But, with the big pumps I have on now, I can remove the heat from the boiler but the hx is not capable of transferring that heat to the tank.
Scott,
You have pressurized storage, so the hx issue doesn’t exist for you. But, you really don’t know what the Laddomat is putting out for flow without having a look at the pump curve. Did you get the one I sent you for my pumps? Head pressure has a huge impact on flow. If the Laddomat says 10 GPM max, you can be sure you are not getting that. I still think your system would work better with a big pump between the outlet of the boiler and the T to the Laddomat. That pump would feed the Laddomat when it needs hot water to boost the return temp and feed the top of the storage tank (or other loads) when the return temp is high enough. I’ve got to believe that the more heat you remove from the boiler, the lower the stack temp is going to be (given the same burning conditions) lower. Probably not a huge difference. But if the fire is making X BTU/hr and you are removing Y BTU/hr, then X - Y is all that is left for the stack.
I think you did send me pics of the inside of you front cover. I’ve not opened mine yet. Probably not going to right now, either. The heads of 2 screws are stripped and 2 of the scews are not like the rest. I’m guessing when it comes off, there is going to be some (well lots) swearing, extracting broken screws, and retapping of holes. Seems like a better summer project. I’m curious, have you adjusted your primary air settings at all?
Since I’m experimenting with the secondary air, maybe I’ll just keep going till I either can’t go any more or I start to see some difference. So far, no change to the burn (visible) and no change to the ash in the lower chamber after the burn.
The other factor I haven’t considered - with the secondary being opened more there is less resistance on the fan. Maybe I could be closing the fan damper some more, too. But, one thing at a time for now.
Anyone know how many turns those secondary screws can be opened? Anything fall apart if I go too far?
How much resistance to flow does a Grundfoss UP26-64 give to a line when it is not running? I would think it is a lot. Not quite like a closed valve, but really close.
The reason I ask - One of the pumps going to the tank has a T just after the outlet. Straight through the T goes into the tank hx. The stub to the side goes to a ball valve. If I open that valve, it Ts into the line that goes to the house right after the line comes out of the tank hx.
So, if I open that hand valve and the pump in the house is not pulling water from the hx, will the pump off the boiler push through the hx coils normally used to supply heat the house? (There is another hand valve I can open so that the other end of the hx is open right to the return manifold for the boiler.) It seems like the 4 coils should be much less resistance than the 300 ft of PEX (round trip), the two flat plate hx in the basement, and the pump in the basement. This basically doubles my hx capacity in the tank.
In the opposite condition, when the boiler is off and the pump in the basement is pulling from the tank, that pump will have two more coils to pull through also. Again, I’m hoping that 2 coils provide less resistance than the pump.
The only other condition is where the boiler is on and the pump in the basement is on. No big deal there, some heat goes direct to the house without going through the tank. No harm there. I do that after being gone for a few days and the tank is cold anyway.
I’ve had pumps like this apart before. It seems like without the impeller spinning you could only get a trickle of water through them. That trickle is less than ideal, but I don’t think it will really hurt me here.
So tell me, did I just find some extra hx capacity for free?
Sounds like you did Steve. Your smarter than me-I think your telling yourself through the writing as I sometimes do. I think Nofossil should think it over or heaterman.
As far as runnung those screws out too far, it will just stop turning at some point, nothing should fall apart. If i remember too, those things are long, you can really have them out far. Id say after mant more full turns it really will not matter at all. The end of those screws is like a flat washer suspended in the free air inside that panel. Tour probably an inch away from the main pipe(s) that lets air go through the nozzils. Opening them more really wont matter the way I see it, and ive tried those things in different spots. Never could see a difference unless run almost completely in. Eric says he noticed a difference from 3.5 to 6. I could not tell, but he probably burns consistant fires better than me to read it better. Your right too about the screws and swearing. They are a poor fit and most of mine are stripped and the whole plate is noisy.
If I tear this thing down (yet again) I will add a pump as you suggest. It would be great to be able to really crank that eko wide open if I were to get behind on a fire, and have the ability to recover quickly.
The screws holding the fan plate in place are short self-tapping sheet metal screws, so I don’t think you’ll have to do any tapping and probably not a whole lot of cussing, to get them off of there.
The secondary air screws can come out as far as you can move them. They won’t fall off.
I did adjust my primary air at first, when I was getting some smoke. I did it because leaddog, I think it was, said that his were closed when he received his boiler from the factory. So I checked mine out and opened them up a bit. When you think about it, all of the air going into the boiler goes through the nozzles one way or the other. If there’s not enough primary combustion air, it seems to me that it would affect the performance of the burn in some way. In my experience, my boiler needs more air in all three inlets than the factory settings.
I’m still confused by your (and barnartist’s) complaint that you lose gasification at some point in your burn cycle. IME, once the thing torches off, it pretty much goes for the duration of the cycle. Sometimes the wood will not fall correctly in the firebox, resulting in incomplete gasification, but that’s only when I try to build a small fire & there’s not enough weight to keep the fuel centered and pushed into the nozzle opening. When you start with a full loaf of wood, by the time the amount of wood in the firebox has diminished to the point where the nozzles aren’t covered anymore, you’re into pure-gas mode anyway.
If you generally fill your firebox full, then I’d say offhand that the smoke and inconsistent gasification have something to do with your air supply.
Scott,
I’ll run another test tomorrow using all the hx coils to heat the tank with the house off and see what happens. Hopefully, I’ll be pleasantly suprised.
Eric,
Obviously, I don’t understand what is going on inside this thing. My thinking is that too much primary air would cause the wood to burn too fast, creating more gas (smoke) than the secondary air can burn, and smoke out the stack. I’m starting to get the feeling that I’m wrong on this?
Maybe I need to try reducing the total air a bit more, and see what happens.
When I first got this thing I would lose secondary combustion all the time. Too much air, not enough air, who knows? I had all kinds of problems. Now that I’ve got a system in place that works for me, I don’t have that problem any more. Really, I think too much and too little total air can cause the problem. With the fans open too far, the upper chamber seems to burn without the wood turning to coal and making a nice bed of coals. With too little air, there isn’t enough heat to sustain secondary combustion. Both cause dark residue in the lower chamber and heavy smoke out the stack. My experience only.
Heck, ours are wide open I think Steve. Maybe actually closing them(primary) some would help the test more. Its just that there freakin inside that panel, and those scews are undersized. You have good results the way you are Steve, I dont blame you for not wanting to dig in there. But Eric seems to have a good flame (gasification) throughout his burn. Eric, how far open are those primary air plates on your right now? are they open all the way? You may have said where they were before, sorry if I forget. Are Leaddogs wide open? You might have something there Steve about too much primary. Al I want here is to be able to leave my Eko with those fans in a good spot for a nice long burn-SLOW. If I start too closed, even with a nice flame at the bottom, it can later smolder a bit, but too open and I will have a high stack temp and thus more heat loss.
4 hour burn is done. Tank rose from 170 to 183. So, 2700 gal times 8.34 lb/gal is 22518 pounds of water. Times 13 for the 13 degree temp rise, and I get 292,734 BTU transferred to the tank in 4 hours, or about 73 kBTU/hr.
What does that mean to me? I don’t really know yet. But, tomorrow I’ll do it using the other hx coils too and see what I get.
The pump on the aquastat is still running, and will be for a while, so the 292,734 number isn’t the total for the burn. There is some time initially to get the boiler itself hot, and now it will keep transferring heat for a good long while to cool the boiler back down.
I know you’ve plumbed you boiler a bunch of times. But, I think you need to come up with a good plan, with feedback from the guys here, and get that storage tank working. I’ve got mine to where I set it and leave it there. Heck, my wife even ran it last week while I was out on business. So I really do have it to where it doesn’t need constant fussing. I think you can too. Until you get the storage working right, blocking one nozzle may be a big help. Otherwise, you need to choose between idling/high stack temps and losing secondary combustion by trying to keep the fire too low.
I too hated this thing when I first got it, but I got over that after a few weeks. I feel bad for you, knowing the pain you are going through with this, and for how long you’ve been enduring it. I’m not the only one here that has one of these working the way I want. Once you get there, you’ll be happy too. And your wife!
Thats great to get all that water up like that in 4 hours, but yet what does 205K eko mean then? does your number divided by 4 hours kind of mean around 55k an hour? Im sure Im wrong on that. At the same time Im not sure I could raise 2700 gallons up that quickly-yet.
73k an hour. You got the right idea, I think you just rounded the first number down too far.
That’s the thing. You’d have to know the test conditions they used to come up with the 205k number. My numbers would probably be higher if the tank was colder, for example. So, if they use a huge storage tank, with cold water in it, and a huge hx, they could get better numbers. And, they might be able to get 205k BTU/hr out of it, but might be doing it at only 50% efficiency from pushing the boiler so hard.
How can that number be that low from 205k. Since you run a pretty good camp there, I’ll use that number as a guide as to what to expect when I add more heat storage.
I wonder what Nofossil thinks of that?
How can that number be that low from 205k. Since you run a pretty good camp there, I’ll use that number as a guide as to what to expect when I add more heat storage.
I wonder what Nofossil thinks of that?
Good analysis. Do that calculation every time, so that you can see what changes actually have an impact. Were you working with really wet wood? I think there’s a point at which moisture really affects the secondary combustion.
My EKO 25 seems to run at somewhere between 50,000 and 60,000 BTU/hr average. It’s rated at 80,000 BTU/hr. I’ve hit that for brief periods, but it feels like running a car at redline.
I expect that as you get secondary combustion dialed in, you’ll see much higher numbers. You should get a pretty good roar out of it, with plenty of flame from both nozzles. I think that you’d only see the rated BTUs with a whacking big pump, pretty cool inlet water, burning kiln-dried hardwood.
sled: I don’t completely understand it myself, so maybe I shouldn’t comment, but I believe it’s safe to say that if you’re getting smoke, it’s probably due to a lack of air somewhere in the system. That’s usually the cause of incomplete combustion. If you’re producing more smoke in the firebox than the nozzles can handle, then my guess is that the secondary air flow needs to increase. I think that too much primary or secondary air will cause overheating and loss of efficiency up the stack, but not smoke. Maybe I’m wrong.
One thing to check might be those secondary air tubes. Take a flashlight and look into each one to see if the air passages are blocked. They’re little holes in the steel pipe, as I understand it. I suppose it’s possible that they can get clogged with creosote and restrict their ability to deliver superheated air to the nozzles. Sometimes those tubes can break loose (they’re only tack welded to the frame) and begin to back out. That will mess with your secondary air adjustment, too. I had that happen to mine and so did leaddog. Everything worked a lot better when I got it fixed.
Finally, I’d consider your air supply to the boiler. Can it get enough fresh air. Try running it with a door or window open (or something) to see if it behaves any differently.
barnartist: I didn’t open them up very much, but I did slide them out 1/2-inch or so from the way they came from the factory. When you first look at those sliders, they look like they’re completely closed. “Ah ha!” you say, before noticing that it’s just the way they were designed. But they can be opened. All I can say is that it worked for me.
im pretty sure mine are open as if not even there. Maybe I should close them down some.
My nozzle tubes were as clean as can be, even as bad as ive burned in the past.
Great analogy NoFo, I could run it and it sounds like a distant jet too.
As I see it, I’m running at roughly 1/3 of “rated” capacity. What I need to figure out is this - Am I limited by the hx in the storage tank or the burn rate of the fire?
As long as running at a lower capacity is not causing, or caused by, system inefficiency, I see no reason to worry about it. Assuming, of course, that I am able to heat my house at that capacity. Really, it’s only the coldest of the cold snaps that have caused me to have to load 3 times a day. And even then, it’s usually every other day that I have to do that.
To be clear, with the timer shutting the boiler down, I always have at least 8 inches of coals left over the nozzles. So I’m not filling it as if the fire box were empty each time. That’s how I get the fire started so easily each time.
Nofossil,
I agree with your assement of hitting rated capacity. Except maybe the sun and moon have to be lined up just perfect, too. And, I think you would take a hit on efficiency doing it. Your car will go 120 mph, too, but it will get better fuel economy at 70 mph. Same work achieved in going a fixed distancy, but one speed uses more fuel than the other.
Tomorrows experiment will be using the other coils in the tank to see if that affect how much heat is transferred. I’m not here every day, and I can’t have the heat turned off every day, so my test runs will be limited. Once I know more about the hx issue, I can decide on how to address the burning issue.
Eric,
Can you tell that I really don’t want to take the cover off? If I do, do I need to take off the jam nuts for the secondary screws? Seems like I’d have to, or the whole thing would have to come off with the cover.
One note of interest - this morning was the first time I noticed a reduction in smoke. So maybe a little more secondary air will do the trick for me? I’ll open them a bit more for tonight’s burn.
Which brings me back to this - if I have to put in more air to optimize the burn to eliminate smoke, but my stack temps go up, and I can’t capture the excess heat to the tank, have I really gained anything? I don’t know the answer to that question either. Maybe I’ll be able to figure it out?
