Midea inverter air conditioner E1 communication failure maintenance training case
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Midea Inverter Air Conditioning E1 Communication Failure Maintenance Training Case Study Case: Double reactor to single reactor caused E1 indoor and outdoor communication protection Yangtze Air Conditioning Maintenance Department Shanghai Product Model: KFR-32GW / BP2DY-M Product Bar Code: 5U18093128030870 Fault phenomenon: Frequency conversion split The indoor unit displays E1 (indoor and outdoor communication failure) fault scope: indoor electrical control, indoor motor, indoor and outdoor connection group, outdoor electrical control, outdoor DC motor, reactor, rectifier bridge fault handling ideas and steps: Step 1: On-site Detect the AC voltage of the internal and external machine 220V, the grounding is safe and reliable, whether the connection line is loose and disconnected, whether the neutral line and the live line are misaligned, and there is no extension pipeline installation. The E1 protection caused by the voltage, grounding and signal connection lines is initially ruled out. Within 2 minutes, the voltage of the outdoor L and N terminals is 220V, and the indoor power output is normal. The DC 2-24V fluctuating voltage between the neutral line N and the communication line S is detected to further rule out the indoor unit failure. Determine the point of failure is the outdoor unit. Step 3: Detect the outdoor unit power line. The rectifier bridge has a 300V DC voltage output. When the P and N power input terminals of the module are detected, it is found that there is no 300V DC voltage between the PN on the electrical control board of the air conditioner. Check again and find that: 1. The newly applied external electromechanical control box and the old version of the electronic control version are upgraded. The new electric control scheme adjusts the dual reactor connection scheme to a single reactor connection control. When the maintenance personnel replaces the electric control, the reactor plugs are misaligned, causing the power circuit to fail to form a closed-loop path. There is no 300V DC voltage input module P and N terminals. . 2. The temperature protection on the top of the TP (CN9) compressor on the new board has been cancelled. One of the reactor CN23 terminals has been cancelled and the exhaust sensor protection has been cancelled. Treatment measures: 1. Use the single-reactor new electrical control after technical improvement to replace the double-reactor electrical control box. The top temperature sensor plug must be covered with electrical tape or the temperature sensor on the top of the compressor can be removed directly. 2. Change the 2 reactors to 1 reactor connection control mode. The original reactor and capacitor model should be adjusted to R8525 + 6uF. The old computer board had two reactors and one capacitor, respectively R1310 + R6025 + 45uF. Adjust the reactor and capacitor according to the wiring nameplate of the new board and connect the wires. See the wiring diagram below.