dirk pitt wrote:very good did67 analysis
actually, the boiler oertli in question is an adaptation with an additional granular burner (of another mark, I think) in addition the regul indicated by laurent is not planned to pilot a valve three ways !!!!
This is what seemed to me ... So, alas, bad pick for our friend Laurent !!!
on the other hand, it has a storage tank of 750litres. I do not know how the exit of the balloon is regulated towards the radiators ???
It is now the only solution to limit the damage: produce hot water with the "least worst efficiency" possible (use the boiler fully and with a minimum of stops / restarts) + use this hot water as sparingly as possible by a regulator controlling the 3-way valve as a function of an outside sensor and, if necessary, of an interior room thermostat ...
I found the doc on his boiler and I think I can help if it's only regul problems because I have deepened the subject on my OKOFEN (not far from a full winter to settle all the parameters impeccable) the installer having been satisfied with the factory parameters. but this winter is nickel and the cons seems to be very reasonable (I think less than 3 tons for 110m² isere)
factory parameters are all-purpose, but often poorly adapted to particular conditions.
1) The Okofen is not the easiest to adjust; the notice on this question is not its strong point; that said, I'm waiting for the cold to confirm, but in a few days, I'm well called (remember that you should not make more than one change of setting per day otherwise you get confused!); that said, I took over the parameters (slope and foot of curve) of my Viessmann and I just adapted a little (my Okofen is less powerful, and the temperature increases are slower with pellets than with fuel ) ... And the Viessmann manual (which I still have) is more explicit. The adjustment of the slope and the foot of the curve is exactly the same, whatever the boiler, which is ultimately only the source of hot water!
2) By definition, the parameters of a 3-way regulation are specific to the house: exchange surfaces (the living surface being only a rough approximation), thermal resistivity of each surface, inertia of the internal partitions (a solid concrete wall does not react like a plasterboard which will not react like a paneling on a wooden frame, etc.), and of course, type of heating - underfloor heating, or radiators of more or less large area, inertia (cast iron, ...) ...
In part, it is therefore quite normal to have to adjust to your own case ... You should not systematically blame the heating engineer! I think that all this must be able to be calculated, but when I see the calculation just for the power, you will have understood that to calculate slope and foot of curve, it is something else!
Laurent's misadventure should shed light on potential candidates for this type of heating:
1) Pellets are a high value and ultimately quite expensive fuel ("
only "30 to 40% cheaper than fuel oil!). It is not the wood that you make yourself during holidays with the beauf tractor in the nearby forest! It's annoying - and tricky - all these confusion around "wood heating"!
2) Boilers at the top are absolutely necessary. Otherwise, it's a debacle!
Putting yourself in the right mind that a pellet boiler is a much more complex mechanism than a fuel or gas boiler. Anyone who is not convinced of this has only to remember that it is much more difficult to light a campfire than a gas campsite! And I'm not talking about successfully simmering a cassoulet - not to say sauerkraut! - with one or the other !!!
3) I would advise as a minimum safeguard to only consider subsidizable products in Germany / Austria. This guarantees 90% efficiency, based on independent tests. I have already mentioned some brands which arrive at around 95%.
Otherwise, you run the risk of being disappointed and losing money. A bit as if we installed a good old cast iron fuel oil boiler from our youth and were surprised that the fuel bill was salty.
I remind the candidates that I have a considerable doc on the performances and emissions of a large number of brands and models. Unfortunately in German. I am willing to share.
4) It is also
absolutely necessary out of respect for the environment, because who says poor efficiency generally says significant increase in emissions - it is not only the CO² in the gases emitted by a pellet boiler, even the best !!!