Apartment ventilator fan setting for keeping apartment warm

Accomodation, House and Garden
1
My apartment is modern and has Bodenheizung (floor heating), and then it has this ventilator unit. I think the model is the Comfoair 180 and then the controller is Comfosense CCF. There are settings for the Bodenheizung and then there are settings for the ventilation, and I think the systems are completely decoupled.

The Bodenheizung has controls in different rooms, with no temperature markings.

The ventilation has either manual fan settings 0,1,2,3, and then it also has a “Comfort temperature” auto mode where you can specify a desired temperature. It says:

> The ventilation unit strives for a comfortable air temperature supply as possible on the basis of a set comfort temperature.

But in this mode, the fan is always on level 2. Presumably it is modulating something other than the fan speed to try and maintain this supply air temperature. But what?

I have the Bodenheizung at absolute maximum at the moment, and find it surprisingly chilly. It’s livable, but I want to at least have some room to adjust. It almost makes me wonder if the property owner has set the main apartment furnace on a really low setting to try to restrict our energy usage. Would I have a way to find out if that were the case? I don’t have physical access to the room where the furnace is.

Again regarding the ventilator, if I wanted the apartment to be warmer, forgetting about how fresh the air is, would I be better off putting it in manual mode on low fan speed 1? Or put it in the auto “Comfort temperature” mode, and set a high temperature? But then the fan just runs on speed 2. How high could I set the temperature before the unit starts to act strangely or will it be fine?

And if I were somehow absolutely desperate to acheive the highest temperature in the apartment, wouldn’t fan setting 0 be the best? Or at this point is it just an efficiency question? How would I even know if the Bodenheizung is maxed-out and straining to keep up or if it is actually achieving the temperature set-point, and messing with the ventilator would not make a difference?

Fan setting 0 is “fan is running at very low speed (Only choose this option when nobody is at home.” 1, 2, and 3 are “low,” “medium,” and “high,” respectively.

2
Presumably the ventilator is sucking in air from outside.

If so this is to prevent mould developing (and potentially you suffocating through lake of oxygen).

If you can turn off the ventilator you should vigorously air the apartment for 10 minutes a day - windows wide open. Heat will be lost but it will be rapidly back to normal...

3
We have this model at home. Even when it's off, it's still in some kind of trickle mode. Ours is set year round to 1.

4
as far as I have seen this "oversimplification" is a standard in new buildings: a simple knob with five positions from low to high.

regarding heating:

Normally there is an underfloor compartment with valves that controls the distribution of heat between rooms, often under the wardrobe at the entrance. The idea is that a "Fachmann" sets it once and for all. Anyway, if you have problems, ask the landlord, or the agency, they will send someone who can probably make some tweaks.

Btw, where I live we have a common heating station for a group of apartment buildings. We have dumb thermostats in apartments and they also change the temperature of water in the system according to the air temperature. With a delay. Sometimes it is too cold and sometimes it is way too warm. I tried to make things better with retrofitting "smart" thermostats, but often the easiest thing to do to put on a sweater.

5
I just realized I could do a simple test-- turn the thermostats down until I hear the click (fortunately this is possible as a way to get some feedback about the “state” of the thermostat).

Indeed the click does not come until I go down to the middle (setting 3). Since they have been on setting 5 (the highest) now for a week or so, it is absolutely safe to say that they have been “always on” and that the temperature is being fully regulated by whatever water temp is coming in. Whether that can be adjusted locally with the Wasserverteiler thing in the under-wardrobe compartment, or whether it has more to do with the global setting for my building/group, we’ll see.