Oköfen boiler and excessive condensation

[kick1602]

Hello everybody

I have a question that I haven't been able to find the answer to and was wondering if by any chance anyone would have the time and kindness to help me out.

A year ago I had an Oköfen pellematic compact pellet boiler installed.
Last winter I noticed that there was a lot of condensation in the smokehouse (I think that during cold periods I collected between 3 and 4 liters of water in 24 hours.
During the intervention of my chimney sweep, he told me that there was too much humidity in the pipes and that the soot was sticking.
I contacted my installer who came to remove the "turbulator" (long metal parts that form waves). He remained very vague on the impact that this will have on performance.

I am worried because during the 2nd chimney sweep my chimney sweep was very surprised by this action.

My question is therefore the following, is it normal to remove these parts to reduce consumption and what will be the impact on performance.

Thanks in advance to anyone who can shed some light on me.

very good day

[izentrop]

Hello, maybe an insufficient rise in temperature?
A tubing diameter that is too large in relation to the heating power?
Insulated tubing allows a faster rise in temperature of the smoke pipe, better draft and limits the risk of condensation
https://www.forumconstruire.com/constru ... hp#6044183

[kick1602]

Hello,
Thank you for your reply.
I will look at your link.

I made a typo in my question.

I wanted to write:

My question is therefore the following, is it normal to remove these parts to reduce condensation (and not consumption) and what will be the impact on performance.

[sicetaitsimple]

My question is therefore the following, is it normal to remove these parts to reduce condensation (and not consumption) and what will be the impact on performance.

Hello,
I would first like to clarify that I am not personally a pellet boiler user. My answer will therefore have to be verified.
But from what I understood from the operation of classic Okofen boilers*, it is that the turbulators make it possible to improve the exchange coefficient between the hot gases and the water in the heating circuit. Removing some (or adding some) also makes it possible to some extent to adjust the nominal output of the boiler.
If the heating engineer has removed them, it is certain that the fumes will come out hotter and therefore less likely to condense in the smoke chamber.
On the other hand, this should be done to the detriment of performance, there will be fewer calories transferred to the water circuit for the same quantity of pellets and more which will go up the chimney.
It should be able to work from a condensation limitation point of view, but at the cost of an energy penalty that is difficult to estimate.

PS:* the pellematic compact is not, I think, a condensing boiler?

[sicetaitsimple]

Complement: on the merits, the remark of Izentrop is to be looked at carefully.
Was the change of boiler accompanied by modifications to the flue, or was it just a modification of the connections on an existing flue, not necessarily adapted to the characteristics of the new boiler?
Seen from afar, it's just a hint, but seen up close, it's a bit more complicated.

[kick1602]

Hello and thank you very much for these answers,

@izentrop
I started reading the subject of your link and my water was flowing just like the subject person, through the inside of the "T".
As for the diameter and the insulation of the ducts for my installation, I will have to go over my invoices.
But if I understood my installer correctly, he removed the turbulators so that the fumes were warmer, which worked because I went from 4L/24h to three drops per month.

@sicetaitsimple
Yes, the idea is to make the fumes hotter in order to eliminate the condensation by removing the turbulators.
But I noticed that he had removed 6 of them (all of them?) and I was wondering if it would be possible to remove only part of them so as not to reduce the yield too much.
I confirm that the boiler is not a condensing boiler and that all the fumistry is new and has been installed for the boiler.


I admit that what worries me is that I asked my installer several times what was going to be the drop in performance of the boiler and he never gave me a clear answer. (In theory the boiler should have an efficiency of 84%)
I would like to know if the solution used to solve the problem is the right one and if it is optimal.

Have a nice evening

[sicetaitsimple]

I would like to know if the solution used to solve the problem is the right one and if it is optimal.

There is no doubt that it is "good" if the condensates have gone from 3 to 4 l/day to a few drops per month.
How "optimal" I don't know. It may be necessary to try, during a future revision, to put back for example 2 turbulators and to compare.
But it's just physics / chemistry, pellets have a water content of around 10%, plus their hydrogen which will produce water during combustion.
Fuel oil, or gas, have a water content normally close to zero, plus their hydrogen.
It is quite normal that the fumes from a pellet boiler have a much higher humidity, and therefore are more likely to condense in an installation that is not specifically designed for it (unlike a condensing boiler where there is is on the contrary sought).

[izentrop]

I went from 4L/24h to three drops per month.

So it's solved...

(In theory the boiler should have an efficiency of 84%)
I would like to know if the solution used to solve the problem is the right one and if it is optimal.

As if it were simple I am not an expert. You're more likely to find one forum like this one https://www.forumconstruire.com/constru ... e_bois.php

[kick1602]

Hello,

Thank you for all this information which will be useful to me.

Yes, the problem is solved except that my installer had given me no technical explanation on his action and above all always answers next to my question on performance.

I also know the forum build but it seems to me, unless I am mistaken, that there is nothing on the Oköfen boilers whereas I had noticed that there were a few discussion threads on this forum.

Good night

[sicetaitsimple]

Hello,

Thank you for all this information which will be useful to me.

Yes, the problem is solved except that my installer had given me no technical explanation on his action and above all always answers next to my question on performance.

Alright, let's be clear...
In my opinion, your installer sold you an oversized boiler compared to your needs and made up for it by removing the turbulators and (I dare to hope?) by plugging the corresponding smoke tubes.
In short, you may have bought a 20kW boiler on paper, but today it only makes 12 or 15.
It's not necessarily dramatic as long as it works properly.
You will see this winter.