A wired Remote Control Display unit is fixed to the wall in the Store cupboard. 

It allows you to control the speed of the airflow around your apartment varying from :-

low at 20%

normal at 34%

manual boost at 55%

purge at 100%

During the day (6am to 11pm) the airflow is normal which runs at 34%.  The sound volume is hardly noticeable. 

At night (11pm to 6am) the airflow is low which runs at 20% with hardly any sound to disturb your sleep.

A higher boost above the normal flow, which lasts for 20 minutes, will be activated when the cooker hob or the shower is used. This runs at 55% with a distinctly higher sound.

A manual boost (55%) can also be activated from the ventilation press buttons in the Kitchen and in the Shower Room. This boost can be stopped at any time by pressing the ventilation button again, or letting it run for 20 minutes. 

COVID-19 virus particles, that may have accumulated in your apartment, can be removed more efficiently by activating a purge at 100%.