EKO 60 low output

[willworkforwood]

I have a friend with an EKO 60 that doesn't seem to be working right. ...

Some fairly basic information missing here that I'm surprised no one has asked about yet. None of it may have anything to do with this problem, but it's typically reviewed in any case.

- What is the load, and how is it distributed? (and a system diagram is always nice to have)

- New install or running in prior years?

-If already existing, any system changes this year? And this could even include things like valves turned for off-season operation, and not turned completely back to where they were last year.

- If already existing, how is this technical performace compared to previous years?

- If already existing, how is it statisfying the load compared to previous years (taking into consideration the unusually cold, recent early season temps)?

- Does he have any temp recording on the load pipes, or used an IR gun to try to evaluate how heat is moving throughout the system?

 

[Nofossil]

It's a primary / secondary. The only load in the examples above is a farmhouse on a secondary loop that heats with baseboard and radiant. The primary loop is quite long - maybe 100' loop length. It has been in service for at least one season prior to this, but with no instrumentation. Performance wasn't ideal. My sense it that it's worse this year in terms of delivering heat.

Bottom line: the main circ is only running 2 or 3 minutes at a time, and is off for 7 or 8 minutes in between. At 8 gpm when the main circ is running, that's only about 2gpm average that's actually being taken from the primary loop and heated.

I'll have him try turning down the recirc. Seems like that would make it worse, but it can't hurt to try.

 

[willworkforwood]

One other question I had intended to ask is firewood quality. Is your friend an experienced and knowledgeable wood burner, or is it possible that he may be using wood with a high MC?

 

[Nofossil]

One other question I had intended to ask is firewood quality. Is your friend an experienced and knowledgeable wood burner, or is it possible that he may be using wood with a high MC?

I don't know for sure. I'll ask. Even so, he should be getting more heat than he's been seeing.

I finally tweaked it enough to get a few minutes of circulator. It seems to stabilize at 9 degrees rise with the recirc running full tilt. On this boiler, the main circ is mounted on the outlet, so both the recirc and the main circ draw from the boiler outlet. Here's another chart. Look at the last cycle. You can see the inlet mirrored to the oultlet, shifted up by 9 degrees and to the right by about 9 minutes. The outlet finally drops below 162 (and kills the circ) when a little drop in inlet makes it through to the outlet.

 

[Nofossil]

Problem solved!

Thanks for all the input. The boiler is being given a thorough cleaning today, but it appears that the root cause may have been that the maximum fan speed on the EKO controller was set to 50%. Mine is the old one that doesn't provide the option to set fan speed, and I never thought that might be an issue. He set the max fan speed to 100% yesterday afternoon and it looks MUCH better. In the graph below, the main circ never shut off at all. The spikes and dips are intentional: any time the wood boiler outlet exceeds 180, the system will start to put heat into storage, which was near ice cold at this time. You're seeing the effect of the storage charge circ cycling on and off.

 

[ewdudley]

If the problem was low heat output, how does your measure of heat output compare now?

 

[Nofossil]

I don't have a direct measurement, but it's now happily maintaining a 12 or 15 degree rise with a higher flow rate than before. He's made adjustments to the primary and secondary adjustments to bring those to factory specs as well. I expect a really good fire tonight.

 

[jebatty]

Have to confess I haven't examined all of the posts carefully, but a summary comment anyway. It seems to me a 60 ought to roar and always put out about 160F+ minimum temp water no matter what the temp of the return water, even with the fan on slower than high speed. Should not the return water control method assure this?

My 140,000 btuh Tarm will do that even on my first firing of the season, when system return water from storage is 65F. The Froling 170,000 btuh also will do that also. The Wood Gun E500 will do that too. As ewd needed to gently remind in a recent exchange we had, a boiler's output has no place to go but the system. So the 60 should be putting out 200,000 btuh at high burn, and if pumps or fans are going on or off or up and down and preventing that from happening, then it seems like a control problem.

 

[Nofossil]

It was pretty clear that it was not putting out anywhere NEAR 200,000 BTU/hr. Setting the EKO fans to 50% speed seems to have been the reason.

 

[timberr]

Nofossil,

I think that is a fair statement to be made in regards to an EKO 60. I have a 25 and always run mine at 50%, don't have any thing other them te,ps probes to monitor out put but storage heats quickly. Main reason for 50% is smoke problem disappears at this level. I haven't seen a 40 or 60 up close and I am assuming that they have the same primary and secondary air setup's as my 25. So it would stand to reason that the 60 would need more "Fan" to deliver enough air for combustion.

 

[huffdawg]

My 40 would be hard pressed to run at 50% fan speed during the first 1/2 hr. to 45 mins. of a burn. I usually start out at 80% and then once the boiler is up past 170f I will turn it down to 60%. If I stay at 80% I see exhaust temps up to 660f.
It will be nice when I have rules in place to keep circ. pumps from coming on while the boiler is trying to get up to a decent temperature. If there is a good demand when the boiler is just starting up it seems kind of like trying to get a car going in 3rd gear.

 

[Nofossil]

It will be nice when I have rules in place to keep circ. pumps from coming on while the boiler is trying to get up to a decent temperature. If there is a good demand when the boiler is just starting up it seems kind of like trying to get a car going in 3rd gear.

Yeah - I actually define several levels of 'hot', and add or shed loads accordingly. In addition, I divide the fire into three phases. During Phase I, the fan runs at full speed. Once it's up to temp, it goes into Phase II where I modulate the fan to try and hold the combustion temp at 1200. Once it has been blow 1200 for long enough, it goes to Phase III - down to coals, and I gradually tail off the fan.

Here's the rules that determine the different degrees of 'hot' and other related boiler states:

// Boiler State Variables
(broken image removed) Set ~Combustion Warm if Combustion is greater than 500.0 with a deadband of 5.0
(broken image removed) Set ~Flue Warm if Flue is greater than 320.0 with a deadband of 5.0
(broken image removed) Set ~Fire Near Target if Combustion is greater than Gasification temp with a deadband of 0.0
(broken image removed) Set ~Fire Detected to TRUE if ~Flue Warm is true and ~Combustion Warm is not true
(broken image removed) Set ~Wood Boiler Active if Wood Out is greater than 155.0 with a deadband of 2.0
(broken image removed) Set ~Wood Boiler Warm if Wood Out is greater than 165.0 with a deadband of 2.0
(broken image removed) Set ~Wood Boiler Hot if Wood Out is greater than 177.0 with a deadband of 2.0
(broken image removed) Set ~Wood Boiler Not Cold if Wood Out is greater than 156.0 with a deadband of 5.0
(broken image removed) Set ~Wood Boiler Overheated if Wood Out is greater than Wood Overheat Limit with a deadband of 5.0
(broken image removed) Set ~Boiler DHW Capable if Wood Out is at least 15.0 greater than DHW with a deadband of 5.0
(broken image removed) Set ~Storage Capable if Wood Out is at least 5.0 greater than Tank Middle with a deadband of 5.0

 

[Nuker]

So many graphs and charts. I have what may be a silly suggestion - ask him to put both circs on low and see what happens.

Second silly suggestion, turn his fan speed down. Way down. If it's at 50% already, shutter those things.

Disclaimer: I didn't read the stuff above me. In my very simple world high stack temps usually mean the fan speed is too high (assuming clean tubes, which are rarely dirty if using nice seasoned wood in my experience) and low output temps mean too much water flow.

Just my two cents.

I thought the same thing from the 500F stack temps mentioned. A good burn was mentioned in the first few posts, along with the high flue temp, made me think a lot of the heat is getting blown out the stack. Slower exhaust air speed would give better heat transfer into the water, and better performance overall. EDIT: Just read the post where it was running better...guess I was wrong yet again. Congrats on getting things going in the right direction!

 

[mr.fixit]

Don't the 60's have 2 fans?
I run my eko 40(single fan) on 50 or 60% all time.
Seems like a 60 ought to run decent on 50% fan speed,but I suppose it also depends on how far the primary and secondarys are open.

 

[taxidermist]

Yeah 50% from 2 fans I run my 60 at 100% with just 1 fan. I would guess his wood is not the best if he added more air and was able to get some heat.

Can you give us all of his settings

Wood moisture
Primary
Secondary
Fan shutter
Wood type

 

[Nofossil]

At the beginning of this thread:

Primary inlets: 7mm
Secondary air: 1.5 turns
Fan shutters: 50%
Fan Speed: 50% max.
Wood: <= 20% moisture (measured)

He had one burn where the only change was raising the fan speed. It was much better, but still not what it should be. He then changed the settings to 9mm / 3 turns / 100% max fan. Subsequent burns have been pretty poor again. I suspect there's something else going on.

 

[TCaldwell]

with 100% fan speed the flue temp will always be high, however if the wood mc is high the secondary burn temp will be low , flue temp high, making standard [dry wood adjustments] poor for wet wood combustion. I assume you have opened your splits and checked mc at the middle. Can scrounge a load of known dry and change the settings back to factory for a run.

 

[taxidermist]

At the beginning of this thread:

Primary inlets: 7mm
Secondary air: 1.5 turns
Fan shutters: 50%
Fan Speed: 50% max.
Wood: <= 20% moisture (measured)

He had one burn where the only change was raising the fan speed. It was much better, but still not what it should be. He then changed the settings to 9mm / 3 turns / 100% max fan. Subsequent burns have been pretty poor again. I suspect there's something else going on.

Sorry i missed it.

The only thing you need to know now is his draft,wood type. And does his draft stay the same during the whole burn.

Sounds to we like a poor wood or a wet wood in the center. But I know your a old pro at these and what your telling me I belive. LOL