Output Signal Feedback (F) An analog output signal (2 to 10 Vdc) that represents the actual actuator stem position is available at Terminal F. It can be used for remote indication of the stem position. When the actuator stem is fully extended, the output signal is 10 Vdc. The output of the signal does not change when the action of the actuator is reversed using W3 or W4, which is set to mA-position, see Direction of Action. Actuator Override The converter output signal override position can be used in freeze protection or similar applications. it forces the actuator into an end position, overriding the control signal. To exercise this function, connect the 24 Vac common (or T2) to either terminal O1 or O2. connecting to terminal O1 fully extends the actuator stem. connecting to O2 fully retracts the actuator stem. The control signal is ignored when the override signal is applied to terminal O1 or O2. this override can be achieved with a switch or relay, see Fig. 9. Fig. 9. Connection for overriding control sigal to drive actuator to specific position. CHECKOUT The ML7421 Electric Linear Valve Actuator can be checked out either directly or using a controller. 1. Mount the actuator for the required application. 2. Check the valve position and make sure that 24 Vac is correctly applied to the actuator. 3. Apply the control signal to the appropriate leadwires to move the valve in the required direction. 4. If the actuator does not move, make sure the actuator is properly installed. 5. If the actuator is correctly installed and does not run, replace the actuator. Direct Checkout Controller Checkout 1. Adjust the setpoint of the controller to call for opening or closing the valve. Observe the actuator. 2. If the valve is closed, it should begin to open. 3. If the valve remains closed, move the setpoint further towards the open setting. 4. If the valve does not move, check for 24 Vac in the actuator power input. 5. If 24 Vac is present and the actuator does not operate, reverse the controller leadwires to determine if the device is miswired. 6. If the wiring is correct, 24 Vac is present on the power input terminals, and