Mitsubishi Heavy Industries KX series air conditioning, indoor unit displays E3 repair countermeasure mm

Mitsubishi Heavy Industries KX Series Air Conditioner, indoor unit displays E3.

Fault Phenomenon: The 7-segment display on the main unit's computer board has no display, while the indoor unit shows E3.

Cause Analysis: Power supply AC380V to the main unit is present. Beijing Mitsubishi Air Conditioning Repair Center confirms that the primary AC220V power supply of the transformer is present, the secondary Blue-Blue AC17V is present, and the secondary Red-Red AC8V is also present. After re-powering the system by cutting off the power again, the fault still cannot be eliminated. Upon checking, the resistance value between A and B signal lines is 0. Further inspection reveals that the shielding wire head of the indoor unit is in contact with the A and B signal lines at the wiring point, causing a short circuit. After modifying the wiring and re-powering, the fault is eliminated.

Countermeasure: Require on-site construction personnel to pay attention to inspections during the construction process.

Beijing Mitsubishi Air Conditioning Repair Center, August 10, 2011.