Unit installation

CDU Installation Guide Page 41
Cooling Distribution Unit
8.1 Summary of Event Messages
See Section 6.4 for instruction on acknowledging events. Events refer to either Warning or Alarm
messages.
Warnings
Warnings are non-urgent events that are not critical to the operation of the unit, but will require
investigation on a routine maintenance visit. The presence of these warnings is identified on the
controller fascia by an amber flashing LED.
Note: Warning titles shown in Green are delayed on unit start up for a default period of 20 minutes -
see ‘Event Delay’ screen 6-7, to allow the system to settle without nuisance event generation. This
delay is also activated when the ‘Suppress Events’ screen 4-5 is activated.
Code: w09 – ‘Water make-up empty’ (engineer to clear)
Fill pumps have been running for more than 3 minutes when reservoir level switch is
made, but minimum system pressure has not been achieved.
Action: Check the make-up container is full, tubes are free of airlocks, container is
properly connected and fill pumps are operational. Check system for leaks.
Code: w20 – ‘Valve 1 fault’ (engineer to clear)
Feedback signal from valve is more than 10% adrift from demand signal - allowing for
positioning time.
Action: Check the wiring connections to the faulty actuator. Try to set the valve
actuator manually using the ‘Manual Control’ function in the controller. Check
the voltage out and the voltage return signal of the valve actuator.
Code: w21 – ‘Valve 2 fault’ (engineer to clear)
Feedback signal from valve is more than 10% adrift from demand signal - allowing for
positioning time.
Action: As above
Note: If both valves go to fault condition, then Warning status will be elevated to an Alarm status
(codes a20 & a21) and unit will revert to and stay with the default valve, until fault has been cleared.
Code: w22 – ‘Primary water low flow’ (engineer to clear)
Becomes active under the following conditions:- Valve demand is at 100%, Secondary
High Temp alarm is active and Primary water temperature is within limits (default 5
minute delay applies).
Action: Check that the chiller is operational and fault free, clean out the primary filter.
Check the load has not exceeded the CDU specification.
Code: w23 – ‘Primary filter dirty’ (self clear)
Differential pressure across filter is greater than 0.6Bar (9PSI) – cleaning required
(default 60 second delay applies).
Action: Flush filter or replace filter screen as described in Section 7.5
TROUBLESHOOTING
Section 8
Typical Alarm screen
!! alarm !!
code : a12
pump 1 inverter
low flow