Azbil FloWing VFR - 4-2-8: Troubleshooting

Azbil Corporation Valve Positioner
Model VFR - FloWing Eccentric Rotary type Control Valves 4-13
4-2-8 : Troubleshooting
Symptom Cause Action to take
No output 1. Incorrect adjustment 1. Refer to subsection “4-2-6 : Adjusting
the positioner” on page 4-10
2. Incorrect supply air
pressure setting
2. Refer to subsection “4-2-6 : Adjusting
the positioner” on page 4-10
3. Clogged restriction 3. Refer to subsection “Cleaning the
restriction” on page 4-11
4. Incorrect mounting of
cam
4. Refer to subsection “4-2-5 : Removing
and installing the positioner” on page 4-7
5. Defective bellows 5. See note.
Output
pressure does
not decrease
1. Incorrect adjustment 1. Refer to subsection “4-2-6 : Adjusting
the positioner” on page 4-10
2. Clogged restriction 2. See note.
3. Bias spring 3. Refer to subsection “Cleaning the
restriction” on page 4-11
4. Bypass cock 4. Switch bypass cock to “ON”
5. Incorrect mounting of
cam
5. Refer to subsection “4-2-5 : Removing
and installing the positioner” on page 4-7
Unsatisfactory
linearity
1. In correct adjustment 1. Refer to subsection “4-2-6 : Adjusting
the positioner” on page 4-10
2. Incorrect mounting of
cam
2. Refer to subsection “4-2-5 : Removing
and installing the positioner” on page 4-7
Large
hysteresis
1. Loose bolts or nuts 1. Tighten the loose bolts or nuts
2. Defective bellows 2. See note.
Sluggish
action
1. Bypass cock 1. Switch bypass cock “ON”
2. Clogged restriction of
bellows
2. See note.
Hunting
occurs
1. Fiction in valve body
or actuator
1. Inspect the valve body and actuator
~Note
The deviation unit requires to be disassembled. Disassembly should
desirably be done by an Azbil Corporation service agent. Disassembly by
the customer is not recommended.