Flowserve APEX 8000 High-Performance Positioner - Manual (Page 9)

move to the failure position. This feature is generally used when the service requires a tight shut off or to prevent throttling near the valve seat.
To adjust this feature, refer to Figure 7 and perform the following:
NOTE: The following procedure applies only when the minimum pressure cutoff feature will be used.
NOTE: The zero and span settings of both the positioner and I/P transducer should be verified as accurate before the minimum pressure cutoff
feature is enabled and adjusted.
1. Connect the I/P module to a 30 to 150 psi air supply pres sure.
2. Remove the I/P module housing cover.
WARNING: Be certain power to the I/P module is discon-nected before removing the housing cover in explosive atmospheres; other-
wise personal injury may occur.
3. Connect an adjustable current source to the terminal block on the circuit board. Apply the desired input signal to the
positioner at which the output pressure is to fall to approx imately 1.7 psi . This signal can range from factory setting of 3.7
to 8 mA.
4. Turn the minimum pressure cutoff pot clockwise until the output pressure drops off Turn the minimum pressure cutoff.
5. Fine-tune the pressure drop-off point by increasing the input signal and then decreasing it through the desired shut-off signal. Observe
the signal value at which the pressure drops off. If the pressure drops off at a lower mA signal than desired, turn the MPC pot counter-
clockwise. If the pressure drops off at a higher signal than desired, turn the MPC pot clockwise.
6. Repeat Step 5 until the pressure drops off at the desired input sign.
7. To disable the MPC feature turn the minimum pressure cut off pot (marked “MPC”) 20 turns counterclockwise or until it makes a clicking
noise.
Positioner Maintenance
NOTE: Refer to NT3000 IOM (VLAIM0047) for I/P module maintenance instructions.
For proper maintenance, proceed as follows:
1. Maintain a clean air supply, free of dust, oil and water. A coalescing air filter for I/P is required to ensure a clean air supply. Check and
maintain filter regularly.
2. Make sure all arms and levers move freely.
3. Check for loose parts.
4. Be sure there are no leaks in the air supply tubing fittings or connections.
5. Refer to the troubleshooting chart on page 9 in case of problems.
Pilot Relay Disassembly and Reassembly
The pilot relay is available as a complete unit and can be easily replaced (See Steps 2 and 18.) Before attempting to correct any problem with
the pilot relay assembly, obtain a positioner repair kit that contains the soft goods most commonly required.
NOTE: Numbers in parentheses correspond to the numbers in Figure 8.
1. Remove the feedback spring (47) and rotate the span and zero arms (40, 46) out of the way.
2. Remove four screws (33) holding the pilot relay to posi tioner base (1). Remove relay from positioner.
3. Remove the nut (25) connecting the flapper assembly (21) to the signal capsule.
Apex 8000 High-Performance Positioner AXENIM0130-06 11/10
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