Cause analysis and treatment methods of common faults of refrigeration unit

1, The compressor cylinder head frosting.

Evaporator return liquid: adjust the opening of expansion valve to increase the superheat of refrigerant return gas.

Excessive refrigerant is dissolved in the oil separator.

2, High exhaust pressure, high and low pressure controller action.

There is non-condensable gas in the system: vent air at the top of the exhaust pipe.

Condenser scaling or dust accumulation: clean the condenser.

The amount of condensed water is small, so measures should be taken to increase the amount of water and improve the working environment of the condenser.

Too much refrigerant: remove excess refrigerant.

Exhaust pipe is not fully opened: fully open relevant valves.

Incorrect setting value of high and low pressure controller. Damaged goods: adjust the high and low pressure controller or replace it.

3. The exhaust pressure is too low.

There is serious leakage in the exhaust pipe or compressor exhaust valve sheet: replace the valve sheet to repair the exhaust pipe leakage.

Improper energy adjustment or failure: adjust the energy mechanism correctly.

4. The exhaust temperature is too high, and the temperature protection module works.

Part-load work: adjust the compressor operation control process to ensure its proper operation condition. Suction pressure is too low: see "Suction pressure is too low fault" for details.

Short circuit of compressor stator winding: overhaul or better compressor motor.

The temperature protection module is damaged: replace the temperature protection module.

5. Inspiratory pressure is too low

The expansion valve opens through the small orifice and blocks the ice: troubleshooting the expansion valve. Scaling of evaporator: clean evaporator. The suction valve is not fully opened: fully open the suction valve. The liquid pipe is blocked, the valve on the liquid pipe is not fully opened, and the filter is blocked: remove the blockage and fully open the valve. Insufficient refrigerant filling: check whether the system leaks and replenish the refrigerant. Too much lubricating oil: check the lubricating oil system to make it normal and drain excess oil.

6.Compressor noise

Valve plate or foreign matter breaks and falls into cylinder: remove foreign matter and repair damaged parts. Excessive lubricating oil and oil shock: immediately stop the machine and check the lubricating oil system to make it normal and release excess liquid. Refrigerant liquid hammer: immediately stop and adjust the expansion valve. Loose bottom corner of compressor: Tighten the bottom corner bolt.

7.Compressor can't start or stop immediately after start.

Power supply or circuit failure: repair the circuit.

Abnormal oil pressure, oil pressure protection action: check the oil circuit.

Action of high and low pressure controllers: See "Exhaust Pressure Overhigh Fault" for details.

Electrical failure of magnetic valve, resulting in low voltage protection: replace solenoid valve.

The oil pressure controller is not reset: reset the oil pressure controller.

Action of temperature protection module: For details, please refer to "Exhaust temperature is too high" fault.

8. The oil pressure is too low

Oil gauge is damaged and oil circuit is blocked: check and correct or better pressure gauge, and clean the blowthrough oil pipe.

Low oil level: add lubricating oil.

Excessive oil pump clearance: adjust the oil pump clearance or replace parts.

Too much refrigerant is dissolved in oil: turn down the opening of expansion valve.

9.Compressor oil flow protection (screw)

Insufficient lubricating oil: observe the oil mirror and add proper lubricating oil.

Fault of oil flow module: Check or replace the oil flow module.

Fault of oil flow switch: Check or replace the oil flow switch.

Fault of oil circuit solenoid valve: Check or replace the oil circuit solenoid valve.

10.compressor overload

The compressor is locked: check the compressor.

Compressor overload operation: it is common in cold air system, please start it in stages.

Abnormal power supply or circuit: check power supply voltage and phase sequence. Repair the circuit.

The set value of idle current is inconsistent with the motor: adjust the set value of idle current.

11.Oil separator oil level is too low.

Insufficient refrigerant oil: add the same type of refrigerant oil.

12.Fan overload

Fan bearing is damaged: replace bearing.

Blade stuck: adjust the blade and eliminate the fault.

The air duct is blocked: dredge the air duct.

Power supply or circuit failure: check power supply voltage and phase sequence. Repair the circuit.

The set value of idle current is inconsistent with the motor: adjust the set value of idle current.

13.Water pump overload

Pump idling, blocked rotation: check whether the waterway is normal.

Abnormal power supply or circuit: check power supply voltage and phase sequence. Repair the circuit.

The set value of idle current is inconsistent with the motor: adjust the set value of idle current.

14. Abnormal cooling water flow

No water supply source or pipeline valve closed: check the water source or cooling water pipeline.

Dirty blockage of water filter: clean the water filter.

There is air in the pipeline: the pipeline exhausts air.

Flow switch failure or abnormal circuit: repair or replace the water flow switch and check the control circuit.