K8041 Fan timer problem


I have some problems with the K8041 fan timer. When the light in the room is switched on, the LED on the PCB illuminates, but the fan(230VAC-14W) connected to the “SK2 terminal block” does not start. The fan makes a slight humming sound nonetheless. A voltage measurement on the SK2 connection provides 158VAC.
Connecting an ordinary tungsten light bulb (25W) instead of a fan gives the following result: 135VAC on SK2 and the light bulb lights up but flashes slightly (same result with another light bulb (35W) in another socket). Apparently the lightbulbs do not light up at full power. Between MT1 and MT2 of the triac I measure about 110VAC, I would expect something close to zero tough.
By only connecting a digital voltmeter, I measure 225VAC on SK2.
I have checked and re-checked the correct positioning of each component and all solder connections.
The fan works fine if connected directly to 230VAC.

Thank you for helping me out.