Flooded type water cooled screw chiller (PCB Control)
58
High/low pressure switch
All compressors have factory-installed high/low-pressure switches. See Table.6.10
Table
– High/low-pressure switch settings
UNIT
High-pressure switch setting
Low pressure switch setting
Protection value
Reset Value
Protection value
Reset Value
MWSC_A-FB3
14bar
9bar
1bar
2bar
Table.6.10
If the high pressure switch continuously opens for 3s during operation, the compressor will be shut down.
A manual reset of the control is required to restart the compressor. If the low pressure switch
continuously opens for 1s during operation, the compressor will be shut down. It will reset automatically
when malfunction gets solved and cleared on the malfunction record page of touch screen. Sometimes if
the malfunction cannot be solved by reset, consider replace the pressure switches.
Evaporator protection-Low Chilled Leaving Water Temperature
PCB is programmed to shut the chiller down if the leaving water temperature drops below 4 °C. When
water temperature rises up to 10
℃
, the safety resets and the chiller restarts. Besides, the chillers are
equipped with antifreeze switch which located on the outlet of chilled water. If leaving water temperature
continuously keeps lower than 3 °C for 3s during operation, the chiller will be shut down. When water
temperature rises up to 10 °C, the chiller resets, but it needs manually reset on the touch screen.
IMPORTANT:
If unit is installed in an area where ambient temperature may fall below 32 F (0° C), a
suitable corrosion-inhibited antifreeze solution or auxiliary electric heater must be used in the chilled
water circuit.
