19
should be no frost or condensation on the gas suction tube. However, frost and condensation
may appear for a very short time period when immediately after starting the machine.
Do not use only one of the indicators from the checklist above to decipher the state of your
refrigerating system. It is advisable to find out two or more abnormal phenomenon, or conduct
comprehensive troubleshooting because several kinds of troubles may share a common
abnormality.
3. ANALYSIS OF TROUBLES AND TROUBLESHOOTING
a. Poor Refrigerating Effect
The “poor refrigerating effect “refers to when the refrigerator operates normally, but does not
cool to the temperature indicated by the thermostat. Possible causes are discussed and analyzed
below:
1) Refrigerant leaks
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
a) 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.
b) 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
