Non -MFT Models: SY products without the MFT on the nomenclature are only used for on/off or floating point applications. They are only going to use the terminals 3 and 4 to open or close the actuator. This voltage on these terminals should correspond with the actuators voltage requirement of the SY (check between terminal 1 and 3 or terminal 1 and 4). When wiring multiple SY actuators in parallel an isolation relay must be use in order to prevent to the actuators.
MFT Models: SY products with the MFT in the nomenclature can be programmed for variable analog control (typically 2-10vdc). Verify the power supply voltage as well as the fuses on the motor board and the MFT board are still good. Verify the control signal is active, reversing the direction on the actuator can help determine if the motor is working. If the motor drives in both directions but does not reach a full open or closed position execute the adaptation function and the signal will automatically rescale to the travel end stop positions.