Air-cooled module air-conditioning refrigeration system parts introduction and common faults

Air-cooled module air-conditioning refrigeration system parts introduction and common faults

1. The main components of the refrigeration system are:

　　 Compressor, four-way valve, pressure switch, solenoid valve, throttling parts, filter, stop valve, one-way valve, oil separator, heat exchanger, liquid reservoir, vapor-liquid separator.

　　 2. The main components of the electrical system are:

　　 Main board, fan, exhaust thermostat, temperature sensor, condensate pump, water level switch, capacitor, transformer, contactor, relay, reactor, etc.

　　Introduction to refrigeration system components and common faults

　　 compressor

　　 1. Classification of compressors

　　 The main suppliers of scroll compressors: Copeland, Hitachi, Daikin, Sanyo, Meizhi, etc.

　　 At present, most commercial air conditioners use compressors mainly:

　　According to the characteristics of compressor structure: rotor compressor, scroll compressor, digital compressor, screw compressor, centrifugal compressor;

According to the driving mode, it is divided into: fixed frequency compressor, frequency conversion compressor (AC frequency conversion, DC frequency conversion);

According to the power used, it is divided into single-phase compressor and three-phase compressor.

2.Compressor wiring method:

3. Judgment methods for common compressor faults:

　　1) Single-phase power supply cannot be started

　　A. Check whether the electrical wiring is correct and whether it is loose;

b. Check whether the voltage between the terminals is normal, use a multimeter to measure the resistance of CR and CS between the terminals of the terminal, RS=SC+RC (a common fault is that the main and auxiliary windings are connected incorrectly, causing the auxiliary winding to burn out and the resistance value drops; when the built-in When the overload protector operates, it is infinite; when the temperature is high, the resistance value will rise);

　　C. Check whether the running capacitor is damaged;

　　D. When an external overload protector is installed, use a multimeter to measure whether the overload protector is on;

　　2) The three-phase power supply cannot be started

a. Check whether the resistance between the terminals is normal. Use a multimeter to measure the resistance between the terminals U, V and W. When it is normal, the three resistance values ​​should be the same (abnormal is short circuit, open circuit or abnormal resistance; when the overload protector is activated The resistance value is infinite; when the temperature is high, the resistance value will rise).

　　B. Check whether the input power supply has phase loss, undervoltage, overvoltage, etc.

　　C. Check whether the compressor temperature is too high, causing the protector to disconnect.

　　3) Start (not compressed):

　　A. For digital compressors, check whether the unloading valve is operating, check the high and low pressures.

　　B. Whether the four-way valve and other refrigeration accessories are normal;

　　C. Whether the suction port is blocked, observe whether the suction and discharge are normal (Hitachi compressor)

　　D. Three-phase power supply, reverse power supply will cause the compressor to reverse.

　　E. Is there any refrigerant?

F.It is absolutely prohibited to operate in the air.

4) There is abnormal sound and loud noise

　　A. When the compressor starts, within 3 to 5 minutes, due to the unstable system, there will be louder sound;

　　B. Whether it is pipe vibration sound, wind blade sound, sheet metal vibration sound;

C.When air is mixed in the system, there will be airflow noise;

d. There is liquid refrigerant in the compressor return air;

　　E. When there are impurities or copper chips in the system, the sound of metal hitting the valve disc will occur.

　　5) The compressor trips immediately after starting

　　A. Short circuit of compressor winding;

　　B. Compressor leakage;

　　C. The compressor lacks phase;

　　D. For the inverter air conditioner, the inverter module will trip if it fails.

　　 condenser, evaporator

　　1) The condenser is a high-pressure component, which transfers the high-temperature and high-pressure refrigerant gas discharged from the compressor to the surrounding air through the tube wall and fins of the condenser and condenses into a liquid.

　　The condenser has:

　　A, water-cooled condenser (shell and tube heat exchanger, double-pipe heat exchanger);

　　B, air-cooled condenser.

　　2) The evaporator is a low-pressure component in the refrigeration system. The low-pressure liquid refrigerant absorbs external heat in it and becomes a low-pressure saturated gas, reducing the ambient air temperature.

　　 evaporator has:

　　A, shell and tube evaporator;

　　G, plate heat exchanger;

C, air-cooled heat exchanger.

3) Introduction of main precautions: (mainly for water-cooled type)

　　A. A water filter should be installed at the water inlet to prevent debris from entering the evaporator and causing blockage. At the same time, the filter should be cleaned frequently to ensure normal water flow.

　　B. After a long-term shutdown and draining water, otherwise the heat exchanger of the air conditioning system will be frozen out.

c. Scaling treatment of the system: After scaling, the pressure difference between the inlet and outlet water will gradually increase, and the heat exchange performance will gradually become worse. Water treatment must be carried out. For organic fouling (algae), alkali-containing solvents (soda water, NAOH)

If necessary, you can add some active detergents and circulate it with a water pump. For inorganic compounds, the reagents to dissolve them are mainly acids, but acids can also dissolve stainless steel, copper, etc., so organic acids (phosphoric acid, formic acid, acetic acid, etc.) are generally used. ). After cleaning, the pipeline must be flushed with clean water.

Four-way valve

　　1) Cutaway view of four-way valve parts