Yes exactly, the peak is at 50rps - and also stays there when I activate full silent mode so maybe the startup phase is excluded by the setting (or 50 rps is still within the reduced power envelope).
Regarding the cycle time: My unit is simply oversized (thanks to the installer insisting on their DIN-compliant heat survey instead of trusting my measurements) - 7 kW would have been more than enough and the 10 kW unit does not modulate to <4kW output. I’ve seen flatlining flow temperatures and somewhat steady-state operation around -10°C. As I have normal radiators with some self-built fans I don’t have the thermal mass to not notice the temperature oscillations with cycles but they’re typically < 1°C.
It’s good to know the Vaillant flow rate measurement is accurate - I was a bit worried my measurements were off because the energy efficiency in terms of required heating power is so much better than my previous 30-year old gas heater.
At the 09.02 firmware, flow rate is constant and just determined by the “Restförderhöhe” setting (no idea what that is in english - it just changes the maximum pressure of the pump to overcome losses in the pipe system). I’m seeing around 1400 when the compressor is on and 1100 when it’s off - minimum allowed flow rate is 1000 l/h for the 10 kW units).