Unit installation

CDU Installation Guide Page 36
Cooling Distribution Unit
OPERATION (continued)
6.4 Acknowledgement of Event Messages
Event messages will break through onto the welcome screen as and when they occur, as in the example
below. Events are categorised into two levels: ‘Warnings’ and ‘Alarms’.
See Section 8.1 for identification of all event messages.
When an event condition occurs, two things will happen:
The initiated event will break through onto the normal screen, the display will then
alternate between the event message and the normal screen. If more than one event is
present, the display will alternate between scrolling through the events, then back to the
normal screen etc.
The event is automatically logged in the Event Log with the date & time at which it was
generated (see Screen 7-1 to review active events and Screen 7-3 to see the full log
history).
The Event Log keeps a rolling record of the last 30 generated events. When the Log reaches the limit of
30, the next event generated will drop the oldest event out of the log etc.
All event messages can be acknowledged by pressing the key once for each event as they break
through. This will stop the alarm(s) from breaking through the normal screen and deposit them in an
‘Active’ list.
After acknowledgement and in order to keep the operator informed that event(s) are still active, the
time and date on the welcome screen will alternate with the number of active events, broken down into
‘Warnings’ and ‘Alarms’ if both are present. Similarly, if the screen is displaying a sub-screen, then the
top right hand corner of the display will alternate between the screen identification number and the
number of active events.
All active / acknowledged events can be reviewed by going to Screen 7-1.
Some events will ‘self clear’ if the event is a transient one (e.g. a temperature hits a warning threshold
then comes back to a healthy condition) or when the fault has been rectified (e.g. a faulty sensor has
been replaced). The self clearing alarms are identified in Section 8.1.
All events that self clear will continue to remain present the Event Log however, until forced out by the
over 30 event rule, or when the Event Log is manually cleared by an engineer after logging on under
the ‘Engineering’ access code.
Events that do not self clear, as identified in Section 8.1 and require operator intervention for
rectification (e.g. to reset a tripped overload) will need to be manually cleared from the ‘Active’ list by
an engineer after logging on under the ‘Engineering’ access code.
OK
Text in top right hand corner of screen
will alternate from displaying the Screen
identification number, to number of
active Events when present (i.e. number
of Active Warnings and/or number of
Active Alarms).
CDU 1.5 3 Alarms
logon
status
service
!! alarm !!
code : a12
pump 1 inverter
low flow
Typical Warning screen
! warning !
code : w20
valve 1 fault
Typical Alarm screen