Urstyring af Kompressor-rens

[Lamborg]

6-8 bar er rigeligt. :-)

[herden]

ok. så ved jeg ca hvor stor en kompressor der skal til. vil gerne ha en som ikke larmer og som kan bruges til andre ting.
uden at koste en herregård 

[michael f]

stjæler lige tråden et øjeblik. michael F eller en af jer andre. hvor mange bar operere jeres kompressor med.
mvh herden

Ca 6 bar ( ganske billig en fra Harald-Nyborg )

[MHES]

Hi Motoz,

Well, you described the problems concerning compressor cleaning while running very clear 
I have had exactely the same experience, maybe it is changed in later software versions, but that is one of the reasons to combine the compressor cleaning with a programmed stop 

When combining compressor cleaning and programmed stop, you make sure you always have a real start-up, and tge stop omly needs to be ex. 10 minutes 

Best regards
Michael

PS. Maybe you understand written english, but I can't write Finish    

I'm using compressor cleaning with kg limit (15kg). It works well so I haven't even thought of using timed stops instead, but I thought I could share a couple of findings:

I noticed that after the set time period without feeding pellet, the compressor blow fired and then right away it started feeding pellet again like it would be in normal running phase. It took quite a while (several minutes) before it noticed that there was no light, and only then did it begin a normal startup, by feeding a normal startup dose and so on.

Since there now was a double dose pellet on the grate (normal startup dose + normal feeding for a couple of minutes) the result was oxygen level 0,0% and black smoke. Because of this I reckoned that it was supposed to be able to startup on leftover ember and continue running without using the electrical heating element at all. Well, I tried lowering the "time without pellet" to 170 seconds, just enough for the light level to drop to zero before firing the compressor blow, and since then it has reliably continued running without a startup sequence after every compressor cleaning. It ignites quite rapidly on the leftover ember (presumably some is left in between the two air pipes, just below the feeding auger) and the oxygen level drops to set value in a couple of minutes almost always without at all dipping below, so it certainly looks a lot better than when it tried to continue, failed, and did a restart.  The longest I have been running without touching the burner (or removing ash from the boiler) is 3,5 tonnes of pellet, and then only a couple of holes in the grate were blocked with very little "ashcake" buildup, so it does seem to work. http://www.pellets.info/viewtopic.php?f=39&t=14192

Anyone else noticed the same? Is this the way it is supposed to be used? Has the behaviour changed in more recent versions?
I'm on V6.33 with a 30kW bio comfort.    (and I do understand written danish (mostly  I'm from Finland...))

[motoz]

Thanks for the answer. But then again, I have a hard time seeing this as a problem, when it seems to work really really well. For instance:

The whole cleaning sequence takes about 5 minutes from when the oxygen reading starts to rise until it has settled again at the desired value. What would be better by letting it cool down completely and doing a cold-start? I ask because to me it seems as it is meant to be run this way, why would it otherwise try to continue running before doing the cold-startup? But from forum-surfing here I get the feeling that everybody else uses a very long cooling down time and a subsequent cold start.

[MHES]

Hi Motoz,

Well, here in the forum you only see a very low percetage of the complete number of units rinning, so to conclude anything from reading here would be wrong 

The stop combined with the compressor cleaning don't need to be a complet cool-down and new cold-start.
If the burner is stopped for 10-15 minuts, the temperature might drop 10 degrees, and that is no problem.
A positive issue by the cooling down the burner grate is the "crackling" of the ashes lay, wich makes it easier to keep the grate clean.

Anyway, if you don't find it a problem that the burner is "overfilled" after the compressor cleaning, then you just continue wit your set-up 

Best regards
Michael

Thanks for the answer. But then again, I have a hard time seeing this as a problem, when it seems to work really really well. For instance:

The whole cleaning sequence takes about 5 minutes from when the oxygen reading starts to rise until it has settled again at the desired value. What would be better by letting it cool down completely and doing a cold-start? I ask because to me it seems as it is meant to be run this way, why would it otherwise try to continue running before doing the cold-startup? But from forum-surfing here I get the feeling that everybody else uses a very long cooling down time and a subsequent cold start.

[motoz]

Hi Michael.
I think you misunderstood what I was trying to say. I did have a problem with overfilling after compressor cleaning. First I tried to solve it by using longer time for "komp_rens_ventetid". That did not make it any better, so instead I tried lowering it. When the komp_rens_ventetid is short enough, the fire ignites all by itself without using the heating element, and the burner never stops to add the starting dose, which is what causes the overfilling.

The left image is with komp_rens_ventetid 300s. After the "blow" it continues to run without fire for a while, stops to add a startup dose and ignites with the heating element. The grate is now overfilled and the oxygen level drops to zero for a while.

The right image is with komp_rens_ventetid 180s. After the "blow" it continues to run, selfignites on leftower "glow", and reaches stable flame rapidly without the ugly oxygen dip and no black smoke.



Of course there are glowing pellet left on the grate with such short cooling time when the compressor fires, but I have not noticed any problems by that, and there is no noticable unburned material in the ashtray. Any thoughts on that?

[MHES]

Hi Motoz,

I fully understand what you said, and I understand that you are so "lucky" that you can keep a small fire after compresor cleaning, because you have found a time-setting for "let the pellets already at the grate complete burn out" which make sure some burning pellets are left on the grate.

However that just mean that you blow burning pellets down in the ash-tray, because you dont give them enough time to burn out and "give" thier energy to the boiler.
Then again, the compressor cleaning is not capable of blowing all the burning pellets down in the ash-tray, and therefore you can start the fire again with the left-over pellets.

In my optic, that is waste of pellets and bad cleaning 

I understand that i somehow compensate for the problem of having the burner to run for 3-4 minutes before the missing fire is detected, and new start-up is initiated, but it is still a bug in the function.

Using my suggestion you will make sure you burn-out all the pellets on the grate, and make a nice cleaning with following correct start-up procedure again.

Anyway, it is up to you how you want to do it, and to decide if you want to blow unburned pellets to the ash-tray 

Best regards
Michael

Hi Michael.
I think you misunderstood what I was trying to say. I did have a problem with overfilling after compressor cleaning. First I tried to solve it by using longer time for "komp_rens_ventetid". That did not make it any better, so instead I tried lowering it. When the komp_rens_ventetid is short enough, the fire ignites all by itself without using the heating element, and the burner never stops to add the starting dose, which is what causes the overfilling.

The left image is with komp_rens_ventetid 300s. After the "blow" it continues to run without fire for a while, stops to add a startup dose and ignites with the heating element. The grate is now overfilled and the oxygen level drops to zero for a while.

The right image is with komp_rens_ventetid 180s. After the "blow" it continues to run, selfignites on leftower "glow", and reaches stable flame rapidly without the ugly oxygen dip and no black smoke.



Of course there are glowing pellet left on the grate with such short cooling time when the compressor fires, but I have not noticed any problems by that, and there is no noticable unburned material in the ashtray. Any thoughts on that?

[motoz]

Ok, then we are on the same page    As I said I have (several times) burned over 3000kg pellet without even looking at the grate (posted link above with pictures how the grate looks after that, the ashtray is then full so it's anyway time to empty it). So in my opinion the cleaning works as well as anyone could wish for. And there really is no visible traces of unburned pellet in the ash. I'm quite certain that the explanation is that the glowing unburned stuff is left between the two airpipes against the backplate, the rest of the grate is clean.

It might be that I'm just lucky, in that case I guess my question ("anybody else running like this") is answered - apparently no. But has anyone else tried? I could be that it doesn't work in the more common smaller burners. By the way, what is the factory setting for the komp_rens_ventetid parameter?

It really seams to me that the burner is meant to be run this way, or alternatively it's as you said just a software bug. In that case the only option would be to use "urstyring" as I really don't like seeing black smoke out of the chimney.

[Birch-Nielsen]

It really seams to me that the burner is meant to be run this way, or alternatively it's as you said just a software bug. In that case the only option would be to use "urstyring" as I really don't like seeing black smoke out of the chimney.

Hi Guys

Guess there's only one way to find out: What does the NBE-Man himself - Mr. Jannich - have to say about this issue eventually? I have my self made some thoughts i this direction, but have as "Everyone else" always used the planned time stop settings. Interesting, motoz, definately 

BR

Folke