Analysis and Repair: Upon inspection during startup, it was found that the temperature difference between the inlet and outlet air vents was only 7°C, with a low pressure of 0.3 MPa. Both readings were on the lower side according to the Beijing Mitsubishi Air Conditioning Repair Center. The high-pressure pipe showed signs of overcooling, and the compressor was prone to overheating protection. When the compressor operation was stopped, the noise disappeared. Stopping the indoor fan revealed a very noticeable refrigerant gas flow sound, confirming that the fault was caused by secondary throttling in the system. By manually checking the evaporator’s several refrigerant distribution branch circuits, it was discovered that the temperature of the last two circuits was significantly lower, indicating a weld blockage. After recovering the refrigerant and re-welding the affected areas, the fault was resolved.
Tip: Gas flow sounds are generally caused by excessive throttling, and the reasons for throttling should be carefully analyzed.
Mitsubishi air conditioning outdoor unit has loud noise and poor cooling effect.
Beijing Mitsubishi Air Conditioning Repair hotline provides analytical data.