IM-P405-46
EMM Issue 5
22
Before dismantling the actuator, consult the instructions given below:
8.1 Actuator with solenoid valve
A
If the actuator does not function check that:
1.
The valve is free to rotate.
2.
The actuator is of the correct size.
3.
The speed control screws, if fitted, are loose (if screws are tightened all the way the
actuator will not operate).
4.
The correct voltage is supplied to the solenoid (the valve coil is tagged with the correct
voltage).
5.
Sufficient compressed air is available at the solenoid valve.
B
If the proper voltage and air pressure have been verified and the
valve is free to move proceed as follows:
1.
Apply the correct voltage to the solenoid valve. Check for a clicking sound.
2.
If no sound is detected:
i) Carefully unscrew the solenoid and solenoid stem from the block.
ii) Re-apply voltage and observe the solenoid plunger. If it does not retract replace
the solenoid valve.
3.
If the solenoid functions, remove both it and the mounting block for a bench test. Connect
with a minimum 3 bar g air supply and correct voltage. Switch it on and off and check
the air flow. Air should flow out of only one outlet port when the solenoid is energised.
(Slight backpressure may be required to shift the valve spool. This may be generated
by obstructing the outlet port).
C
If the actuator functions but exhibits leak or power loss accompanied
by leakage proceed as follows:
1.
Check the voltage. It must be within 10% of the specified voltage.
2.
Check the compressed air supply. Ensure that no intense pressure drops occur as the
unit is cycled. Loss of pressure can cause incomplete shifting of the spool valve in the
block or at one of the piston seals of the actuator. A leaking piston seal will usually leak
on either cycle. On spring return actuators, piston seal leakage will show at port B on
the air manifold flange. A leaking spool valve will require replacing. Leaking piston seals
can be cured by replacing the 'O' rings with new ones.
8. Fault finding
Summary of Contents for ABV21i
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