When your heating or heating and hot water is on , the motor is activated ,therefore consuming about 5 watts . In the hot water only position , the motor is deactivated ,so using no power (except what your timer ,programmer is using)
valve sticks in the the CH only position .In this position , the synchron motor is activated. I don't think the motor is at fault, because I've tested it; it turns when connected to a 240 v supply with a resistance of approx 70Kohms . This is the fifth motor (in the same system) I've had in 10...