Miele APFD 200 Operating Instructions Manual page 53

Connecting the ad-
apter
Insert the hose adapter into the quick-release coupling on the  in-

sert until it engages with an audible click.
The collar on the coupling is pushed downwards in the process. .
As soon as the collar has snapped back, the hose is pressure-tight.
 Danger to health
Damaged quick-release couplings can force wash water into the air
regulator.
Have the quick-release coupling replaced with an original spare
part if it is no longer possible to hear the click clearly or the collar
does not snap back fully.
en - Areas of application
53