Unit installation

CDU Installation Guide Page 42
Cooling Distribution Unit
TROUBLESHOOTING (continued)
Code: w24 – ‘Primary water low temp’ (self clear)
Primary water temperature has exceeded the 4°C (40°F) threshold (default). Alarm will
cancel when temperature rises to 5°C (42°F) or above (default 2 minute delay applies).
Action: Check chilled water supply.
Code: w25 – ‘Primary water high temp’ (self clear)
Primary water temperature has exceeded the 11°C (52°F) threshold (default). Alarm
will cancel when temperature falls to 10°C (50°F) or below (default 2 minute delay applies).
Action: Check chilled water supply.
Code: w26 – ‘Secondary water low temp’ (self clear)
Secondary water temperature has exceeded the 2°C (4°F) below set point threshold
(default). Alarm will cancel when temperature rises to 1°C (2°F) below set point or
higher (this alarm will only activate when at or below dew point for a period of 3
minutes or more while in operating dew point tracking mode).
Action: Check operation of control valve(s).
Code: w27 – ‘Secondary water high temp’ (self clear)
Secondary water temperature has exceeded the 2°C (4°F) above set point threshold
(default). Alarm will cancel when temperature falls to 1°C (2°F) above set point or
lower (this alarm will activate at a pre-set default level of 20°C (70°F) while operating
in dew point tracking mode – see Screen 6-3-12) (default 2 minute delay applies).
Action: Check operation of control valve(s). Check chilled water supply flow and
temperature. Ensure data rack load does not exceed CDU cabinet capacity.
Code: w35 – ‘Check Water Make-up Level’ (engineer to clear)
Pressure at PS1 has dropped more than 0.2Bar (3PSI) below system minimum
pressure setting while unit is running in automatic mode and fill pumps have been
activated (default 10sec delay applies).
Action: Check amount of fluid in make-up container and re-fill if necessary. Check
system for any sign of leakage.
Code: w37 – ‘Sec over pressure’ [when set as a warning] (engineer to clear)
Pressure at PS1 has increased above the set default value of 7.5Bar (105PSI).
Note: Can also be configured as an alarm (code a32) with unit shutdown.
Action: Most likely cause will be excessive heat build up in the system or a breech
between primary & secondary circuits within the plate heat exchanger. Check
for high temp alarms, relieve pressure at drain point. Remove heat exchanger
& replace.
Code: a38 – ‘Primary water low flow’ (engineer to clear)
Becomes active under the following conditions:- Valve demand is at 100% &
Secondary High Temp alarm is active while Primary Temp is within limits (default 5
minute delay applies).
Action: Check that the chiller is operational and fault free.
Alarms
Alarms are more urgent events that are critical to the operation of the unit and will require immediate
attention. The presence of these Alarms is identified on the controller fascia by a red flashing LED.
Note: Alarm titles shown in Red will initiate a unit shutdown.
Code: a01 – ‘635 board failure’ (self clear)
Communications break between controller mother board & daughter board.
Action: Check connections between the boards.
Code: a02 – ‘Primary temp out of range’ (self clear)
Reading from primary temperature sensor T1 is outside the nominated range of -31°C
to +66°C (-23.8°F to +150.8°F).
Action: Check sensor connections to the control board