Troubleshooting of Rack & Pinion Pneumatic Valve Actuators

Mechanical Problems

Problem

Possible Error

Solution

Feedback position and actual position are not the same

Actuator and valve are mounted 90°rotated in relation to each other

Remove actuator from valve. Check assembly code of actuator. Put both valve and actuator in “Closed” position. Mount actuator on valve

Valve is in “Closed” position, actuator is in “Open” position and will not move anymore

Valve does not reach the completely “Closed” or “Open” position

Limit stop screws are not set correctly

Readjust the limit stop screws

Insert is not mounted properly

Mount the insert in the right position.

 

Remark: Rotate insert to one cam = 22.5°

Pressure too low

Apply pressure as per sizing

Sizing is wrong

Check valve torque data with actuator torque data

Pinion is mounted in the wrong position

Reassemble actuator

Actuator rotates, valve does not

No coupling between actuator shaft and valve spindle

Install a coupling between actuator shaft and valve spindle


Pneumatic Problems

Problem

Possible Error

Solution

Actuator does not react to electrical control signal

There is no supply pressure at the actuator

Supply the right pressure to the actuator

Actuator does not react good to electrical control signal

There is sufficient supply air pressure but insufficient supply air capacity

Take care the supply air tubing has the right dimensions

Supply pressure too low, causing pilot operated solenoid valve to fail

Check that supply pressure at the actuator and solenoid is sufficient to operate the actuator

Solenoid valve is not mounted properly

Check the solenoid valve mounting

Speed control throttle (if present) blocks air flow

Turn the speed control more open

Manual override (if present) on the Solenoid Valve is locked

Unlock manual override on the solenoid valve

Air leakage between actuator and solenoid valve

Sealing between solenoid valve and actuator is not mounted air tight

Reassemble solenoid valve taking care, that all seals are in place

Double-acting actuator will only move to “open” position

Actuator has wrong

Solenoid valve configuration

Mount a solenoid valve suitable for doubleacting Actuators (4/2 or 5/2 function)

Check that conversion plate on solenoids, that have both 3/2 and 5/2 functions, is in the right position


Electrical Problems

Problem

Possible Error

Solution

Actuator does not react to control signals

Control wiring. Power supply wiring or feedback wiring are not right connected

Connect all wiring in the right way

The power supply voltage is not is not the same as the voltage of the applicable solenoid valve

Connect the right power supply voltage

There are problems with position feedback after sending the actuator to either the “Open” or “Closed” position

The wiring of the feedback signals may be switched

Connect the feedback wiring in the right way



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We are COVNA Automations, one of the top manufacturers of quarter turn actuators and automatic control valve products in Dongguan, China with 18 years experience. Our industrial experience will be useful in your business and projects.

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