37MGRA EH03 / EC07 / EC71 Fan Speed Is Operating Outside of Normal Range Diagnosis and Solution

Diagnostic codes covered

EH 03(EH03), EC 07(EC07), EC 71(EC71)

• EH 03 – IDU Fan Speed Out of Control
• EC 07 – ODU Fan Speed Out of Control

Description: When indoor / outdoor fan speed keeps too low or too high for a certain time, the LED displays the failure code and the AC turns off. Recommended parts to prepare: Connection wires, Fan assembly, Fan motor, PCB Troubleshooting and repair: —N Indoor or Outdoor DC Fan Motor (control chip is in fan motor) With the power on and when the unit is in standby, measure the voltage of pin1- pin3, pin4- pin3 in the fan motor connector. If the value of the voltage is not in the range shown in below table, the PCB needs to be replaced. Outdoor DC Fan Motor (control chip is in outdoor PCB) Release the UVW connector. Measure the resistance of U-V, U-W, V-W. If the resistances are not equal to each other, the fan motor needs to be replaced. Otherwise, the PCB needs to be replaced.