Junkers CW400 a NEST

   Hi, sorry for writing in English but I guess you're the only person who can help me.
Recently I moved to new place heated by JUNKERS CERAPUR ACU ZWSB 24/28-3E with CW400 (with outside thermometer) mounted on boiler. I also connected NEST thermostat to LR and LS on boiler just to check how it works.
My question is whether the settings on cw400 are more important from what I set on nest. For example. I've programmed temperatures for day/night (22 Celsius and19 at night) on CW400. Now what happens If I want 25 on nest. Will it heat to 25 or 22 max or maybe I should set something completely else on CW400?
Don’t know if you understand what I mean. If any questions please let me know.

   Hi, I'm sorry for my very bad English.
Operating both thermostats is not a good idea. A better option is to put the CW400 in a room and activate room temperature control (service menu).

When two thermostats :-(
NEST tells the boiler you can heat yes/no (LS). He switches off the boiler when the room temperature is reached.
The CW 400 mounted on the boiler regulates the heating water temperature according to the outdoor temperature (the boiler does not operate at room temperature). The set temperatures (22°C / 19°C) are imaginary and make a parallel shift of the heating curve. It is important to have a well-set heating curve. The boiler only switches off if the boiler calculates a low heating water temperature.

To the question: The heating switches off at 25°C (NEST) or if it is warm outside (depending on the setting of the curve and other parameters on the CW 400). I need more information for a range of CW 400 settings. Where are you from; what are you heated (radiators, underfloor heating); as much as possible to the heating system, preferably photos.

   Thanks for your answer. I'm from Poland.
My heating is all in-floor radiants.
I've connected nest just for tests to understand how it works together with cw400. So now you've explained me temp settings on cw400 without measuring it in room. It just moves heating curve.
I know that the best idea is to move cw400 to my room for now but technicans said that the best position to fit the CW400 is boiler because it will control water temperature.
Next there will be connected salus kl08nsb to Lr Ls in boiler to divide heating zones and in every room, there will be mounted Salus quantum sq610 thermostat.
I'll will try to mount the whole system myself because of long waiting time for technicians but the whole point is how to set cw400 on boiler?
Here are photos of my current settings.
It just crossed my mind if I could completely disable heating in cw400 and leave it only for water. But I don't know if the boiler will heat then...
Sorry for too many questions but I'm still learning since it's completely new to me. The more I read the less I know :-b
BTW your English is awesome.

   Hi, I already have an overview of your situation.
The in-floor heating is always best operated with the lowest possible heating temperature.
The in-floor heating needs relatively long time to cool down and heat up. Regulate the same temperature in the rooms by flowing through with individual “snakes” (red trubes). Regulation of individual snakes by thermostats will not be beneficial. The price to performance ratio is bad + it's bad for the boiler and the thermal comfort.
Earlier I asked you where are you from because it is needed to set up the heating curve. It is important whether it is for example in the mountains or in the valley. Please send me the number of the heating curve on your boiler and your city.
My advice:
 1) You need well set heating curve on CW400. The time program gives the boiler a parallel shift of the heating curve. Base value is 20°C. Above 20°C the curve is moved up, below 20°C curve is moved down. I would reduce the heating a little just for the night. There is no need to use a room thermostat.
 2) Well-set flow rates with individual snakes. Same or desired temperature in all rooms. Snakes also don’t need room thermostats.
 3) On the boiler, find the “Maximal shutting down temperature” (Max. vypínací teplota = 74°C) and lower the value to the same as the maximal output temperature of the boiler water (Max.teplota na výstupu = 48°C). It should be the maximal temperature for the in-floor heating but since I don’t know it, we will use this one.

   What do you mean by number of heating curve you wanted me to send?
Unfortunately, the whole Salus thing (kl08nsb + sq610 thermostats) is already on my way. Should get them on Wednesday. So, I need to set up cw400 well together with thermostats :/
I live in Tuchola (kujawsko-pomorskie), Poland

   Hi. I already found it. The number of heating curve is not. There is a fixed start of the heating curve (20°C outdoor temperature / 25°C heating water) and the end of the curve “Dimenzovaná teplota” which tells the boiler the heating water temperature (45°C) at -20°C outdoor temperature. This setting is fine for you and the beginning.
I would start without the Salus things. If you then add them (I do not think), open the LR / LS when all the snakes are closed.

   Yes, it is fixed but you can configure cw400 with starting point and set your own heating curve.
What about temp schedule? I know it's imaginary but don't really know how to set it up. Now I have 19 (changed to 18) during night and 25 days. Is it OK? I guess I'll have to observe it and change to my desired temp inside especially at winter. Thanks

   Hi. Yes, only the end point can be set for the heating curve. This is how its inclination is made.
Temperatures in the temperature schedule will not correspond to reality. During the day, set a value that corresponds to the desired temperature. For example, set 25°C to keep the temperature at 21°C in the room. This effect must be tested. It is different for each house. Do the same for the night temperature. If the heating curve is set correctly, the room temperature should be stable at any outdoor temperature.

Many many thanks for your help.

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