The reasons for this failure is a system funnelled exists inside, but why don't pressure leak? Is mainly due to the system is running line temperature change is big, such as heat bilges cold shrink reason funnelled to appear, and suppression was conducted at room temperature, it is not easy to find funnelled, which can raise the pressure observation in leak detection. This situation has found more in the actual maintenance; There is another more easy to ignore the situation, is a refrigerator in the use of many years later, with frozen oil and refrigerant compressor coil insulation varnish eutectic, heavy impurities inside the system or product, make the capillary walls appear "wax" phenomenon, namely capillary inner diameter, in the equivalent of capillary length increases, reduce refrigerant flow, lead to refrigeration result is bad. The general solution is to cut off the capillary half a meter, the fault can be ruled out.ugbservice manual download site