Concentration %

Freezing temperature (℃)

Concentration %

Freezing temperature (℃)

Concentration %

Freezing temperature (℃)

4.6

-2

19.8

-10

35

-21

8.4

-4

23.6

-13

38.8

-26

12.2

-5

27.4

-15

42.6

-29

16

-7

31.2

-17

46.4

-33

Fault

Possible Causes

Detection and Troubleshooting Methods

Excessive discharge pressure

Air or non-condensable gases in the system

Bleed gases via the refrigerant port and re-evacuate if needed

Cooling tower fan malfunction

Inspect and repair the fan to restore operation

Excessive suction pressure

See "Excessive suction pressure"

High ambient temperature

Insufficient cooling water flow

Check the cooling water system and increase the water flow.

Low compressor oil level

Check the oil level through the sight glass and add refrigeration oil

Low discharge pressure

Low suction pressure

See "Low suction pressure"

Refrigerant leakage or insufficient charge

Detect leaks and recharge refrigerant

Cooling water temperature too low

Check if the cooling tower capacity is excessively large or if the ambient temperature is too low

Excessive suction pressure

Discharge pressure too high

See "Discharge pressure too high"

Excessive refrigerant charge

Release part of the refrigerant

Liquid refrigerant flowing from the evaporator into the compressor

Chilled water inlet temperature exceeds maximum allowable value

Check and adjust the expansion valve, ensuring its temperature-sensing bulb is in tight contact with the suction pipe and fully insulated from the outside

Low suction pressure

Clogged filter drier

Replace the filter drier cartridge

Expansion valve improperly adjusted or malfunctioning

Adjust to the appropriate superheat temperature, or check if the expansion valve's temperature-sensing bulb is leaking

Insufficient refrigerant in the system

Detect leaks and recharge refrigerant

Chilled water inlet temperature significantly lower than specified value

Insufficient chilled water flow

Check if the pressure in the evaporator's inlet and outlet pipelines is too low, and adjust the chilled water flow rate

Compressor shutdown due to high-pressure protection

Cooling water temperature too high

Cooling tower fan malfunction

Overhaul the cooling tower fan

Incorrect high-pressure shutdown setting

Check the high-pressure switch

Compressor shutdown due to motor overload

Voltage too high or too low

Check that the voltage does not exceed or fall below the rated voltage by ±10%

Discharge pressure too high

Refer to "Discharge pressure too high"

Cooling water temperature too high

Check if the cooling tower capacity is too small

Overload component malfunction

Check the compressor current and compare it with the rated full-load current specified on the compressor

Motor or terminal short circuit

Check the corresponding resistance of the motor and terminals

Compressor shutdown due to built-in temperature protection switch activation

Voltage too high or too low

Check the voltage; it must not exceed the specified range mentioned above

Discharge pressure too high

See "Discharge pressure too high"

Chilled water inlet temperature too high

Compressor built-in temperature protection switch failure

Replace the component

Insufficient refrigerant in the system

Check for fluorine leakage

The compressor shuts down due to low-pressure protection

Drier filter blockage

Replace the drier filter element

Expansion valve failure

Adjust or replace the expansion valve

Incorrect low-pressure shutdown setting

Check the low-pressure switch

Insufficient refrigerant

Recharge the refrigerant

Loud compressor noise

Insufficient compressor refrigerating oil

Check the oil level in the sight glass and add refrigerating oil

The compressor fails to start

Overcurrent relay trips and fuse burns out

Replace the damaged components

Control circuit not connected

Check the wiring of the control system

No current

Check the power supply

High-pressure protection or low-pressure protection

See the section on suction and discharge pressure faults above

Contactor coil burned out

Replace the damaged component

Incorrect power phase sequence connection

Reconnect and swap any two wires

Water system failure, water flow switch open circuit

Check the water system

The operation display shows an alarm signal

Check the alarm type and take corresponding measures

Incorrect setting of start-stop time

Check and reset the settings

Temperature sensor detects temperature exceeding set value

Check and reset