**Haier Refrigerator: Starts Normally but Does Not Cool**
**Fault Phenomenon:** The refrigerator, after being stored for a year and restarted, can start up normally but does not cool.
**Analysis and Repair:** This fault is generally caused by a leak in the refrigeration system. Separate high-pressure and low-pressure tests were conducted to check for leaks. A segment of capillary tube was welded onto the outlet of the filter and sealed at its end. A three-way valve pressure gauge was connected at the pipe joint with the compressor's high-pressure tube. The connection between the capillary tube and the filter was sealed using gas welding, and another three-way valve pressure gauge was installed at the pipe joint connecting the capillary tube to the compressor's low-pressure tube. After installation, 1.2Mpa ammonia gas was injected into the high-pressure end, and 0.8Mpa nitrogen gas was injected into the low-pressure end for pressure testing. After maintaining pressure for 12 hours, it was observed that the high-pressure remained unchanged, while the low-pressure dropped to 0.3Mpa. Based on this, it was determined that there was a significant leak in the low-pressure part of the refrigeration system. This refrigerator is a double-door, frost-free direct-cooling model with a concealed condenser. To locate and repair the leak, it would be necessary to damage the cabinet and remove the thermal insulation layer.
Firstly, the top panel and upper/lower doors were removed, and the cabinet was inverted with the back facing upwards. The spot-welded areas were pried open, and more than half of the back steel plate was pulled apart from top to bottom. The foamed insulation layer was dug out, revealing many corrosion spots on the evaporator of the freezer compartment. Nitrogen gas pressure testing was used to detect leaks. Suspected points were surrounded with modeling clay shaped into concave forms. Low-pressure nitrogen gas was injected through the three-way valve until the pressure reached 0.8Mpa. Soap water was then applied inside the concave shapes formed by the clay, and bubbles emerged in three places on the back of the freezer evaporator, confirming these as leakage points.
After cleaning and drying the leaking areas, sandpaper was used to remove the oxidized layer, followed by cleaning with acetone. JC-311 dual-tube adhesive was used to repair each leak point individually. Then, 0.7Mpa nitrogen gas was injected for a 24-hour pressure test, during which the pressure remained stable, indicating that the leaks had been successfully repaired.
**Filling the Foaming Agent:** Before filling, the surface of the refrigeration system pipes was cleaned with ethanol. In a container, two liquids (A and B) for foaming were mixed evenly and heated to 40℃, then quickly poured into the area requiring foaming until the excavated part was fully refilled. The back panel of the box was reshaped and glued to the new thermal insulation layer with adhesive. The entire refrigeration system was then flushed with nitrogen gas, evacuated, and the specified amount of refrigerant was added. After testing the machine, the refrigerator resumed normal cooling operation, and the fault was eliminated.
**Source of Article:** Beijing Haier Refrigerator Repair Center
[http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3455410](http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3455410)