Flooded type water cooled screw chiller (PCB Control)
MCAC-CTSM-2012-11
54
fault occurs during chiller operating, the chiller will stop according to protective stop program. Both
compressors are shut down and water pumps and cooling tower fan stops in accordance with
normal shutdown procedure. When fault record gets cleared and both temperature and time
condition gets satisfied, the chiller can restart.
Cooling Water flow failure
PCB controller begins to detect cooling water flow switch after water pumps get energized 180s.
The switch will disconnect if water flow less than set point and water flow loss signal will generate if
it lasts for 5s. During chiller operation (including dual heads unit), any flow switch disconnects for 5s
continuously, Unit stops according to protective stop program.
If cooling water flow fails, cooling water pump and cooling tower stops after 60s delay; chilled water
pump stops after 600s delay.
Note: fault can be cleared after power re-energized and it needs to be confirmed manually, then
when both temperature and time condition gets satisfied, the chiller can restart.
Temperature sensor failure
Entering chilled water temperature sensor short circuit/open circuit, display entering chilled water
temperature fault and chiller stops according to abnormal shutdown program. After the sensor reset,
fault on screen must be cleared manually; when both temperature and time condition gets satisfied,
the chiller can restart.
Leaving chilled water temperature sensor short circuit/open circuit, display leaving chilled water
temperature fault and chiller stops according to abnormal shutdown program. After the sensor reset,
fault on screen must be cleared manually; when both temperature and time condition gets satisfied,
the chiller can restart.
Entering cooling water temperature sensor short circuit/open circuit, display entering cooling water
temperature fault and chiller stops according to abnormal shutdown program. After the sensor reset,
fault on screen must be cleared manually; when both temperature and time condition gets satisfied,
the chiller can restart.
Leaving cooling water temperature sensor short circuit/open circuit, display leaving cooling water
temperature fault and chiller stops according to abnormal shutdown program. After the sensor reset,
fault on screen must be cleared manually; when both temperature and time condition gets satisfied,
the chiller can restart.
Discharge temperature sensor short circuit/open circuit, display discharge temperature fault and
chiller stops according to abnormal shutdown program. After the sensor reset, fault on screen must
be cleared manually; when both temperature and time condition gets satisfied, the chiller can
restart.
Over/under
voltage
When power supply voltage is less than 90% or more than 110%, corresponding alarm over voltage
or under voltage occurs. The chiller will stop immediately according to abnormal shutdown program.
Fault on screen must be cleared manually; when both temperature and time condition gets satisfied,
the chiller can restart.
