Black traces under pellet boiler exhaust duct

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gek
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Black traces under pellet boiler exhaust duct




by gek » 02/02/23, 17:08

Hello,

I had an Okofen pellematic 12kW boiler installed this summer to heat my house.
Well, it was miserable to find pellets and in the end I got them quite expensive (€520 per ton delivered in bulk).
Apart from that we are quite happy with the operation of the boiler.

I have noticed since the beginning of winter that the end of the exhaust duct was very black (although the smoke coming out of it is not particularly dark) and especially above the outlet, the grass has turned black.

Is this normal or worrying in your opinion? You would suspect a pellet quality or installation problem (I don't trust the installer).

Thank you for your enlightened opinions.

IMG_20230202_090514.jpg


IMG_20230202_090522.jpg
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Christophe
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Re: Black marks under pellet boiler exhaust duct




by Christophe » 02/02/23, 17:16

In the duct it's completely normal: it's combustion dust...the trace on the grass is more bizarre...but it may be normal because it looks like it corresponds to the radial holes at the end of the chimney (what function do they have? Is there a vortex propeller in the end part?)

Normally you also have to have a container to empty regularly on the smoke outlet near the boiler?

My experience with pellets is limited to a few hundred kg of pellets burned in my boiler stove: heating-insulation / THERMOROSSI-h20-34-error-no-temp-resis-improve-the-burning-at-home-t15658.html
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gek
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Re: Black marks under pellet boiler exhaust duct




by gek » 02/02/23, 17:46

Yes, it's especially the tracks on the grass that appeal to me.
The house is for sale and during the visits I am systematically asked what is going on and I dry up, which is why I would like to have opinions from owners of boilers with a suction cup outlet to find out if it is classic or not.
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Re: Black marks under pellet boiler exhaust duct




by Christophe » 02/02/23, 17:50

You did not answer: what is the use of the vents?

If, as I suspect, there is a vortex there, that's completely normal (and I think this part shouldn't have been mounted horizontally...)

Can you take a photo with the flash of the exit or inside one of these holes?
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gek
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posts: 101
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Re: Black marks under pellet boiler exhaust duct




by gek » 02/02/23, 17:54

Actually I didn't answer, I don't know the answer, I'll try to take the picture you suggest next week when I'm back in the house.

Thanks for your help anyway.
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Christophe
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Re: Black marks under pellet boiler exhaust duct




by Christophe » 02/02/23, 18:07

Ok we'll see, in my opinion this part is a vortex aerator which will centrifugal the fumes and improve the draft when it's windy...

But I could be wrong...I'll do some research...
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sicetaitsimple
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Re: Black marks under pellet boiler exhaust duct




by sicetaitsimple » 02/02/23, 18:09

Christophe wrote:because it looks like it corresponds to the radial holes at the end of the chimney (what function do they have? Is there a vortex helix in the terminal part?)

I think it is a concentric flue installation, the combustion gases are exhausted through the inner tube and the combustion air is taken in through the space between the outer tube and the inner tube.
It is not abnormal for some condensation to occur, but normally there is a slight slope which should cause them to flow towards the boiler to be evacuated.
It doesn't necessarily seem dramatic, but it's actually not very "presentable".
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Re: Black marks under pellet boiler exhaust duct




by Christophe » 02/02/23, 18:19

Ah if it's a suction cup (the output is weird anyway) in this case just put your hand on the vents to see if it sucks...

A more precise photo will tell us what it is.
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gek
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Re: Black marks under pellet boiler exhaust duct




by gek » 02/02/23, 18:24

I promise, on Monday I'll do all that for you and we'll make progress on the diagnosis.
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sicetaitsimple
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Re: Black marks under pellet boiler exhaust duct




by sicetaitsimple » 03/02/23, 17:39

Christophe wrote: in this case just put your hand on the vents to see if it sucks...

Definitely! :D
After the "purgers" which were "vacuum breakers" of your solar installation, here are the "vents" sucking!
Good, but actually getting your hands on it when the boiler is working will allow you to see clearly.
By the way, if Gek can check whether or not there is a slope on this pipe? Normally it should rise slightly away from the wall.
And moreover, even if it certainly has nothing to do with the observed phenomenon, what is the height of the outlet of the pipe in relation to the ground? The photo does not really allow to estimate it, but normally it is minimum 2m.
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