Exhaust air systems (extractor hoods, living room ventilation systems, fans) which are connected to the house mains with a Schuko plug and where the radio switch (receiver) is covered with a metal cladding (as is the case, for example, with so-called island hoods.) The external antenna of the radio switch (receiver) must be fixed at a distance of approx. 10 cm without contact with the metal cladding, e.g. on the ceiling.
The magnetic contact switch on the window (BL220FTX radio transmitter) monitors the position of the window sash. If the window is open or the window sash is tilted, the transmitter sends enable signals to the radio receiver every 10 seconds and the exhaust air system can run. If the window is closed, no more enabling signals are sent and the exhaust air system is switched off after approx. 30 seconds of run-on time.