Haier RF-8888-279, Service Manual

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19
Analysis of Trouble
The refrigerant leaks will result in an insufficient refrigerating capacity. This will lead to
lower gas suction and exhaust pressure as well as hotter exhaust gas. The exhaust tube will
become extremely hot, and the sound of gas flowing from outlet of the capillary will become
louder than usual. After shut down, the balance pressure in the system is lower than the
saturation pressure corresponding to the same ambient temperature.
Remedy
Locate the refrigerant leak points immediately, and note welding points and parts where the
leaks occur. While troubleshooting, pay attention to those parts that are liable to leak, check
main connection points for oil seepage and tubing for cracks. After repairing the leak points,
refill the refrigerant. If you have problems detecting the leak points, charge the system with
nitrogen to help identify leaks. Drain the system of the nitrogen before refill with
refrigerant.
2) Too much refrigerant in the system
Analysis of Trouble
If amount of refrigerant in the system exceeds its nominal capacity, the excess refrigerant
will displace the evaporator. This will reduce the heat-dissipation area and decrease the
refrigerating efficiency. Malfunctions caused by excess refrigerant are: gas suction and
exhaust pressures increase, condenser becomes hotter, the electric current of the
compressor rises, frost forms on the evaporator and gas return tube, and the refrigerator
temperature drops slowly.
If excessive refrigerant has been charged, the liquid refrigerant that cannot evaporate in the
evaporator will return to the compressor. This will cause “liquid striking.” The liquid
refrigerant evaporates and effervesces as soon as it flows into the refrigerating oil at the
bottom of compressor. If the condition is severe, foams will cover the inside the compressor
housing and be sucked by the piston, causing damage to the components of compressor.
Remedy
According to the operating procedures, it is mandatory to turn the machine off. After several
minutes, open the refrigerant charging tube and let the refrigerant escape from it, replace
the dry filter, refill the refrigerant after evacuating, and then seal the charging port.
3) There is air left in the refrigerating system
Analysis of Trouble
Residual air in the refrigerating system will reduce its refrigerating efficiency. Major effects
are an increase in temperature of the segment from the compressor outlet to the condenser
inlet and an increase in gas suction and exhaust pressures. However, the gas exhaust
pressure will not exceed its rated value. Due to the air in the system, both the gas exhaust
pressure and temperature will rise. In addition, the sound of gas flowing will become
intermittent and louder.
Remedy
Turn off the refrigerator, and wait for several minutes. Next, open and evacuate the tubing.
Then refill the system with refrigerant.
4) Low efficiency of compressor