Azbil VDC - Spring Compression Adjustment; Positioner Adjustment

Control Valve Adjustment Azbil Corporation
4-2 VDC, VAC, VST, VAA - Diaphragm Control Valve
4-2 : Spring Compression Adjustment
This adjustment must be made after lift adjustment.
Direct acting actuator
Connect air tubing to the diaphragm chamber to supply compressed air.
Apply low end of the pressure as specied on the name plate to the diaphragm
chamber, and adjust by tightening the spring to ensure that the index on the scale
starts to move below OPEN; and when the higher end pressure is applied to the
diaphragm chamber, the index shows SHUT.
Tightening of spring adjuster can be made easily with no air pressure to the
diaphragm chamber.
Reverse acting actuator
Connect air tubing to the diaphragm chamber to supply compressed air
Apply low end of the pressure as specied on the name plate to the diaphragm
chamber, and adjust by tightening the spring to ensure that the index on scale starts
to move beyond SHUT, and when higher end pressure is applied to the diaphragm
chamber, the index shows OPEN.
Tightening of spring adjuster can be made easily with no air pressure to the
diaphragm chamber.
4-3 : Positioner Adjustment
Make this adjustment after both lift adjustment and spring tightening adjustment have
been completed.
CM2-AVP300-2001
Single acting electro/pneumatic valve positioner:
Model: AVP300, 301
OM2-8310-0200
Single acting electro/pneumatic positioner: Model HTP
OM2-8313-0100
Single acting electro/pneumatic valve positioner: Model HEP15, 16, 17