Azbil Corporation Valve Positioner
Model VFR - FloWing Eccentric Rotary type Control Valves 4-11
(6) Turn the zero adjustment knob so that the output pressure of the positioner
becomes the upper limit of the actuator spring range. When this is done, the
indicator should indicate “S”.
(Example: If the actuator spring range is 98 - 200 kPa {1 - 2 kg/cm²}, set the
output pressure of the positioner to 200 kPa {2 kg/cm²}.)
(7) Set the input air pressure to 20 kPa {0.2 kg/cm²}.
(8) Loosen the lock screw with a screwdriver (-) and adjust the SPAN control so that
the indicator indicates “0”.
(9) Repeat steps (5) to (8) several times.
(10) After the adjustment has been completed, tighten the lock screw of the SPAN
control with a screwdriver (-).
4-2-7 : Maintaining the positioner
Operating precautions
(1) Use only clean ltered air for the air supply, lest the nozzle or pilot relay should
become clogged with foreign particles contained in the air supply.
(2) When the positioner is installed outdoors, be sure to install the positioner so that
the positioner cover is vertically positioned in order to prevent ingression of
water.
Troubleshooting
If the positioner experiences problems or it happens to malfunction, refer to the
troubleshooting chart on page 4-13 and follow the procedures described therein.
Cleaning the restriction
If the restriction has become clogged with foreign particles and the positioner starts
malfunctioning, remove the M5 bolts (hex-hole head) and M3 bolt (hex-hole head)
with 4 mm and 2.5 mm allen wrenches, respectively; remove the spacer, and clean the
restriction with a 0.3 mm wire.
Be sure to insert the bias spring when assembling the pilot relay.
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