User guide

page 77 of 102
Fault Possible cause Remedy
❑
No display.
➨
Electrical power cord
not plugged in, electri-
cal supply failure?
✔
Plug in power cord.
Check fuse.
➨
Device fuse blown?
✔
Identify cause of failure.
Replace device fuse at
switch output of VNC 2 or
at diaphragm pump.
➨
Device switched off?
✔
Switch on controller and/
or pump.
➨
Other than above men-
tioned causes?
✔
Contact local distributor.
❑
Display disappears,
internal overload
protection activated.
➨
Too much load (e.g.,
valves) connected?
✔
Check current draw of
the connected devices
(pump, valves).
➨
Thermal overload at
controller, ambient tem-
perature too high?
✔
Ensure sufcient ventila-
tion.
➨
Short circuit at connect-
ed valves?
✔
Replace valves.
➨
Short circuit at the
RS 232 plug?
✔
Check plug and cable.
➨
Other than above men-
tioned causes?
✔
Contact local distributor.
❑
Pressure reading
incorrect.
➨
Pressure transducer
decalibrated?
✔
Readjust VNC 2.
➨
Humidity in the mea-
surement chamber?
✔
Let the pressure trans-
ducer dry, e.g., by pump-
ing. Readjust if neces-
sary. Determine and
eliminate the cause for
humidity.
➨
Pressure transducer
contaminated?
✔
See ”Cleaning the pres-
sure transducer”.
➨
Other than above men-
tioned causes?
✔
Contact local distributor.
❑
Error message
”ErrValve”, two
blips*.
➨
External venting valve
removed or defective?
✔
Connect or check valve or
replace with a new one or
recongure without valve.
Switch VNC 2 off/on.
Troubleshooting