Bray 6A Series O&M Manual - Manual (Page 27)

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Series 6A Operation & Maintenance – Troubleshooting
6A O & M : 27
Fault profile (symptoms) Possible cause(s) Remedial measures
Positioner remains in “RUN 1”. Initialization started from the end position
The response time of a maximum of 1 minute was
not observed
Network pressure not connected or it is too low
A waiting time of up to 1 minute is essential
Do not start initialization from the end position
Provide the network pressure
Positioner remains in “RUN 2”. Transmission ratio selector and parameter 2 do
not match the actuator type.
Incorrectly set stroke on the lever
Piezo valve does not activate
Check settings: see leaflet: “Device view (7)” picture as well
as parameters 2 and 3
Check the stroke setting on the lever. See table 2
Positioner remains in “RUN 3”. Actuator actuating time is too high Open the restrictor completely and/or set the pressure PZ (1)
to the highest permissible value
Use a booster if required
Positioner remains “RUN 5”,
does not go up to “FINISH”
(waiting time > 5 min)
“Gap” (play) in the positioner - actuator - control
valve system
Part-turn actuator: check for the firmness of the grub screw
of the coupling wheel
Linear actuator: check for the firmness of the lever on the
positioning shaft
Remove any play between the actuator and the control valve.
Remedial Measures Table 1
Fault profile (symptoms) Possible cause(s) Remedial measures
“CPU test” blinks on the digital
display approximately every two
seconds.
Piezo valve does not activate.
Water in the pneumatic block (due to wet com-
pressed air)
At an early stage, this fault can be rectified with a subsequent
operations using dry air, if required, in a temperature cabinet
at 50 to 70°C
Otherwise: repair
1)
In the manual and automatic
modes, the actuator cannot be
moved or can be moved only in
one direction
Moisture in the pneumatic block
Piezo valve does not activate (a
gentle click sound is not audible
when the “+” or “-” buttons are
pressed in the manual mode.)
The screw between the shrouding cover and the
pneumatic block has not been tightened firmly or
the cover got stuck
Tighten the screw firmly; if required realign cover.
Dirt (swarf, particles) in the pneumatic block Repair or a new device; clean and/or replace the built-
in fine screens
Deposits on the contacts between the electronic
printed circuit board and the pneumatic block
may develop due to abrasion owing to continuous
loads resulting from strong vibrations
Clean all contact surfaces with spirit; if required, bend
the pneumatic block contact springs
Remedial Measures Table 2
Fault profile (symptoms) Possible cause(s) Remedial measures
Actuator does not move. Compress air < 1.4 bar Set the supply air pressure to >20 psi
Piezo valve does not activate (a
gentle click sound is however
audible when the “+” or “-” but-
tons are pressed in the manual
mode.)
Restrictor valve turned off (screw at the right end
stop)
Open the restrictor screw by turning it counter clockwise, see
leaflet, “Device view (6)”
Dirt in the pneumatic block
Repair 1) or a new device: clean and/or replace the built-in
fine screens
A piezo valve activates
constantly in the stationary auto-
matic mode (constant setpoint)
and the manual mode.
Pneumatic leakage in the positioner - actua-
tor system; start the leakage test in “RUN3”
(initialization).
Rectify leakage in the actuator and/or feed line.
In case of an intact actuator and tight feed line; repair
1) or a
new device
Dirt in the pneumatic block, see above
Remedial Measures Table 3