Bistre formation in thermopoele pellet

[Ahmed]

Kesle, you write:

The water circuit passes precisely in the lower insulation of the living room, below it is the uninsulated garage, that's why I wonder about the overconsumption between 60 ° and 70 ° of water .

It is necessary to maintain the temperature of the water in the stove well above the dew point, this does not imply that the whole circuit is at the same temperature, since you can and must play with the setting of the mixing valve : thus the problem of increased losses does not arise.
Further:

I heard that a pipe that is too big or too long increases the "draft", suddenly the fumes would be less well evacuated and therefore would lead to the creation of bistre in the pipe and in the stove ... true, false?

If the draft is greater due to the characteristics of the duct, the fumes would be better evacuated ...
For this type of device, the smoke extraction is done mechanically by a fan, so the influence of external parameters should not be decisive ...

[Did67]

I heard that a pipe that is too big or too long increases the "draft", suddenly the fumes would be less well evacuated and therefore would lead to the creation of bistre in the pipe and in the stove ... real false?

Regarding the pellet I can indeed do the test, I'm waiting for your explanations, I'll watch tonight the spec on the package but I take it to a pro wood.

1) The opposite is true: the longer the chimney (vertically), the more draft there will be. This also has the disadvantage, on a piloted stove, of increasing the air flow for nothing, and therefore energy losses! In a pellet stove like a pellet boiler, you just want enough air so that the combustion is as perfect as possible (a very slight ventilation). This is adjusted via the fan depending on the pellet feed. And this is the big progress represented by these electronically controlled combustion stoves! All overventilation is about throwing calories ... down the chimney! Thus in an "open fire", 50% of the energy passes through the chimney. To reach 90% or even close to 95% efficiency, pellet boilers ventilate just what is needed. Not a bit more!

On the other hand, a too large pipe reduces the draft ... (for the same height)

2) To determine the humidity of the pellets, proceed as follows.

Weigh a certain amount of pellets (put a layer of 1 to 2 cm in an open, large dish, which can be put in the microwave). To note.

Put in the microwave (like 1 minute at medium power). Stay nearby: if it "grows", stop. Otherwise, go out and weigh.

Restart. Exit. Weigh. If the weight has dropped, start again

Continue like this as long as the pellets do not "tan" and as long as the weight drops ...

At the end, when the weight no longer drops, note the weight.

The difference between the very first weighing and the very last gives you the mass of water.

Divide the mass of water thus measured by the total mass at the start (1st weighing) and multiply by one hundred: this gives you the water content of the pellets in%. If more than 10% is not good. It is above the norm. We can go down, at good producers / good vintages to 5 or 6%. We then have less condensation and above all, a higher calorific value (the evaporation of the water contained in the pellets consumes part of the energy produced!).

[edit: sorry, ahmed, I see your answer now; but as almost always, we agree]

[Did67]

It is necessary to maintain the temperature of the water in the stove well above the dew point, this does not imply that the whole circuit is at the same temperature, since you can and must play with the setting of the mixing valve : thus the problem of increased losses does not arise.

I don't know if this kind of stove manages a mixing valve, linked to climatic regulation. It is undoubtedly simpler: a circulator and flow adjustment by thermostatic taps ... If the desired temperature is reached, the flow decreases, the "reserve" of water heats up and reaches its maximum, the stove stops. ..

But the fact remains that you absolutely have to stay above the dew point, that's for sure!

[Ahmed]

No need to be sorry, because your answer is more precise than mine.
I jumped at your percentage of losses in an open fire, but I see that you have corrected!: Wink:

With regard to regulation, wouldn't it be possible to modify the installation to incorporate a manual mixing valve? That does not seem complicated to me ... unless the rudimentary system that you describe allows the adequate adjustments ....

[Kesle]

Here are the specs of the pellet I put;

ALSO A1
Ø6mm ± 1mm
Length 3,15 to 40mm
PCI> = 5,0 kWh / Kg
Humidity <9%
Ash content <= 0,5%

Knowing that I store it on a pallet in my uninsulated garage, can I recover moisture?

Regarding the ash rate I still suck quite a bit every day ...

[Did67]

Yes, these are the standards.

Except the PCI (calorific value), or they promise more than the standard (which is only 4,6 kWh / kg). It’s probably pure softwood. Many producers are doing better than the norm and advertise this 5 kWh / kg. If they put it on the bag, they should hold it, otherwise it is reprehensible as consumer deception.

Storage, if the bags are not damaged, should not change anything.

You have to keep your exchangers clean. Because if they shrink, the air flow decreases, the combustion is worse, more particles are formed, it settles, it further reduces the flow ... It's a vicious circle.

Because the electronics control the speed of the fan, which is supposed to provide the necessary flow. But if the circuit is congested, the flow decreases.

The other reason for a high production of particles being too wet pellets. This moisture cools the combustion. Combustion at lower temperature is worse, more particles, which "blacken" ...

[Kesle]

Hello, thank you for your answers

Rosé point <60 ° if I understood correctly so never go below 60 ° water temperature

My stove does not stop once the temp is reached it maintains minimum power (reminder P1 to P5)

Regarding the ashes indeed they are black, I am doing the humidity test this evening, pure resinous indeed

For the circulation of water it is indeed a circulator, on the other hand how to know if my exchanger shrinks? I vacuum the ash once a week via 2 small traps in the lower part of the stove, in addition to the daily cleaning of ash in the combustion chamber.

For my pipe that I advised you a lot of info for me sorry, reduce the Ø and / or the height?

Thank you in advance

[Did67]

1) The turbulators must disassemble, right?

2) I don't think the conduit should be blamed.

[Kesle]

Hello

Yes the turbulators are removable but you have to purge the stove because the room that I have photographed has a water circulation on the edges (heat recovery from the fumes?)

Only access is the 2 traps in front or I can clearly see that one of the 9 springs is blocked in are driven, but it is the consequence and not the cause of my problem.

download / file.php? id = 3122 & mode = view

In this photo we also see the 2 purges on each side of the room in the upper part

[Kesle]

Hello

I did the pellet test this week so I have 22gr of water in 306gr of pellet or 7,2% humidity which is not surprising compared to what the supplier announces.

I went to a friend's house this week and I saw that its air intake was plugged in to pull it out while at home I shoot directly at the back of the stove so I pull the ambient air, it can play for my problems ?

The stove has been at 60 ° for 1 week and nothing seems to improve: here are photos of the combustion chamber and the ash tank which is a little orange (rust?) And the magnificent fittings behind the stove (irony)