Ytc YT-1200L, User Manual, Page: 20 / 21

Troubleshooting

Positioner does not respond to the input signal.
① Check supply pressure level. The level must be at least 1.4 kgf/cm 2
② Check if input signal is properly supplied to the positioned. The signal should be 3-
15 psi.
③ Check if the positioner’s nozzle has been blocked. Also, check if the pressure is
supplied to the positioned and the pressure is being exhausted through the nozzle.
If the nozzle has been blocked by any substances, please send the unit to YTC for
repair.
④ Check if feedback lever has been installed properly.

The pressure of OUT1 reaches exhausting pressure level and does not come back
down.
① Check A / M switch. If the switch has been damaged, replace the switch or pilot
relay valve.
② Check for a gap or damages between the nozzle and the flapper. If damaged,
please send the unit to YTC for repair.

The pressure is exhausted only by A / M switch.
① Check if the positioner’s nozzle has been blocked. Also, check if the pressure is
supplied to the posiioner and the pressure is being exhausted trough the nozzle. If
the nozzle has been blocked by any substances, please send the unit to YTC for
repair.

Hunting occurs.
① Check if safety spring has been displaced. <Next to pilot relay valve>
② Check if the size of actuator is too small. If so, insert an orifice in order to reduce
the pressure flow rate.
③ Check if there is any friction between the valve and the actuator. If so, increase
actuator’s size or reduce the friction level.

Actuator only operates by on / off.
① Check pipe connection
② Check cam direction

Linearity is too low.
① Check if the feedback lever is properly installed. Especially check if the feedback
lever is parallel to the around at 50% point.
② Check if zero and span has been properly adjusted, that is not too low or not too