Floating control actuators with ...-3 part number generally do not need a diode (DR/DKR butterfly actuators being the exception) but actuators with ...-MFT part number may need a diode.
Most but not all Belimo MFT actuators have internal diodes and do not need an additional external diode. When a MFT actuator with a programming code for floating control is ordered and an external diode is required, the external diode will be provided and referenced in the datasheet wiring diagram. The standard industry part number of the diode is 1N4007. An 1N4004 will also function.
To determine if a diode is required check the wiring terminations on your actuator. If only one control input is present (Y1 #3), a diode is required. Most new generation MFT will have a second input with integral diode (Y2 #4). IF an old generation MFT with external wired diode is replaced by a new generation MFT with a Y2 #4 input the wiring does NOT need to be changed since they function the same.
Note that the actuator must be powered by 24VAC.
