Help with Oxigen tuning

[tn]

LOL, yes that's what you get when you try a foreign language>
Not that English is my mother tongue, I am actually Dutch living in Ireland since 1994.

Anyway, I think the cleaning of the burner plate combined with Playing with the Oxygen regulation is showing some results.
I had this at 100% initially. Now I first put it in 50% then on 100% and then on 40%.
http://www.beara.org/photo/stg2.jpg

You see that in the middle section there are more swings, and that the third section at 40% seems best.
I'll keep it like this for a while to see what happens.
Regards
Jouke

Hi Jouke

Still you have quite big swings in oxygen level.
but your high pellets is only 9 and 24 KW would by about 30, so you are unning at very low effekt, compared to your burners 24 KW.
But you probably have enough effekt for your size house at your current high setting.
You have a screw, that is designed for 24 KW, so it is not very accurate at low effekt.
meaning it proabaly gives you different amounts of pills from time to time, and this could also be the problem.
Have you tryed to see/hear if the screw is giving the same amounts of pills every time it start, or it's very different.
A low screw angle will be more accurate than a high angle.
No more than 30-45 degrees is usefull.

Also a chimney draft regulator is good to keep constant air draft.

[tn]

Dear Hilsen, (Is that your correct name?)
I really appreciate that you take all the time to write about my problem in detail. I am sure we will now kill it.
To be sure the problem did not always exist. It started on a particular day, and I have been unable to discern what causes the change.

Have you changed the type of pellets you are using, or are there nig difference in length of pellets.
Do you have a lot of crushed pellets in your screw.
Those things can change how accurate the amounts from the screw are.
The swing in your oxygen seem to be in a very fixed cycle, i think that has to do with the screw position, perhabs a swing per revolution.
Again the screw is moving very litle per time, and it's a big screw 24 KW.
But when it has been working, something must have chenged the accuracy of the screw.
And now your oxygen control try to compensate for this inaccuracy and that is very difficult because it's not static.

Just my thoughts.

best regards
Torben ( thats my name)

[joukeder]

Hi Torben,
What do you think of the cleaning times are they OK? Could it have something to do with that?
Th pellets are all one delivery so they are the same.
The angle of the screw (Auger) that feeds into the boiler is high it starts out at only 10 degr. then curves up to about 55 degr. where it falls into the down pipe.
I will test (measure ) pellets fall to find out if the feed is stable.
Also re-weigh the 6 mins amount.

Regards,
Jouke

[tn]

Hi Torben,
What do you think of the cleaning times are they OK? Could it have something to do with that?
Th pellets are all one delivery so they are the same.
The angle of the screw (Auger) that feeds into the boiler is high it starts out at only 10 degr. then curves up to about 55 degr. where it falls into the down pipe.
I will test (measure ) pellets fall to find out if the feed is stable.
Also re-weigh the 6 mins amount.

Regards,
Jouke

Hi

I don't thik the problems is caused by the cleaning. It's only 4 sec each 10 min and the periodtime for the sving is about 20 min.
It seem that the swing is less with smaller gain on the oxygen control.

But one think that could be nice to see is haw big the swings are with oxygen controll set to "just showing".
Also to se how much the low and high pellets values is changed over the 20 min with oxygen control set to on. Note down the low and high values each 5 min or something like that.
I don't know special much about the flexiable screw you are using, but in mine the screw moves from side to side inside the pipe in some cycle, and give most when it's in the lower side.
The speed on the screw is about 8 revolutions per min it runs, but the movement from side to side is much slower.
But try to look on the values for about 20 min, and perhabs that give you some idea about what is going on.

[joukeder]

Hi Torben,
With Oxygen regulation the high is usually in the area of 18-23. Lows around 0.5-4

I switched to Oxygen show only and switched Auto combustion on.
What happened was that Low goes to 4.5 high to 33 as you correctly computed.

Then Oxygen shoots down off the chart to 0.1 And stays low like that.
I am steering the system through Stoker control Sw. But on the woody box I saw that there is another parameter called Blocking time in the Oxygen menu. It is set to 30Min. Do you know what this is? (I am using the latest firmware 4.19)

I think I first need to get it working right without oxygen control.

Regards,
Jouke

[joukeder]

I measured the output of the Auger in 1 min steps:
1 233 250 280 232 234 237
2 250 267 270 238 398 240
3 240 214 195 94 281 260
4 305 250 253 51 309 333
5 220 221 220 185 267 351
6 216 257 255 432 407 351

Totals 1464 1459 1473 1232 1896 1772

[tn]

Hi Torben,
With Oxygen regulation the high is usually in the area of 18-23. Lows around 0.5-4

I switched to Oxygen show only and switched Auto combustion on.
What happened was that Low goes to 4.5 high to 33 as you correctly computed.

Then Oxygen shoots down off the chart to 0.1 And stays low like that.
I am steering the system through Stoker control Sw. But on the woody box I saw that there is another parameter called Blocking time in the Oxygen menu. It is set to 30Min. Do you know what this is? (I am using the latest firmware 4.19)

I think I first need to get it working right without oxygen control.

Regards,
Jouke

Hi Jouke

When you have the 0.1 in oxygen value, does you then have a lot of smoke from the chimney, and is the display showing the same value.
With 0.1 there should be smoke, otherwise the oxygen measuring is wrong.
But you are right about trying to have it to run without oxygen control as the first step, and then use your smoke level to adjust high and low setting to just no smoke level.
I don't know about the new oxygen parameter, but will try to investigate.
Your auger feed is inaccurate, but it does not seem to be in a fixed cycle.
How about your air blower , is that running ok . I think about if there are any dirt in it blocking the weel from time to time, so it can't run freely.

[tn]

Hi Torben,
But on the woody box I saw that there is another parameter called Blocking time in the Oxygen menu. It is set to 30Min. Do you know what this is? (I am using the latest firmware 4.19)

Regards,
Jouke

It's a parameter that stops feeding pellets, if the oxygen level has been below the target for the specified time.
So 30 min meens that it has no effekt in real.

[joukeder]

Hi Torben,
I feel very assured that you are looking over my shoulder. It is so good that you verify and challenge my train of thought. Thanks!

When manually controlling burning and putting the high auger at 30 Oxygen goes down to .1 and certainly a lot of smoke exits the chimney stack. Burning is dark red and light is very low on the lux meter.
Back to auger high at 21 and Oxygen is around 7.2 and NO smoke.

I have a computer controlled telescope. It has only so-so mechanical gear. The designers compensated that by having the electronics compensate for the peculiarities of that gear train. They say its cheaper then making better mechanics and it works very well!

Extrapolating that to the burner you would expect that the designers know that the auger feed is not all THAT accurate anyway and compensate that by steering the auger to compensate for the feed anomalies. If that is so, we are perhaps looking at a feedback problem? at the Oxygen gain of 100 it was perhaps overcompensating and oscilating.
Has anyone experimented with the PID parameters?
Or do you still think its mechanical?
I cleaned the burner unit including the ventilator with pressured air a few days ago. There was not too much debris in it anyway. The ventilator is working very freely. It has a very long wind down time.
Whats bothering mee is why would it burn about OK at 21 AUger high where it should be about 33?

Regards
Jouke

[joukeder]

I said 30 minutes but the display acutally does not say minutes, just 30. So I so just assumed they were minutes. Sorry. One should never ASSUME anything in this area.
Perhaps we could play with this.

Regards
Jouke