The product is fully operational despite the noise, when Q3 is activated. This is true for all 230VAC smart relays.
This noise is because there is a coil located close to the Q3 coil on the Zelio PCB, this resonates only when the Q3 coil is activated.
This noise is because there is a coil located close to the Q3 coil on the Zelio PCB, this resonates only when the Q3 coil is activated.