Troubleshooting Guide
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Only training and service purposes.
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Error diagnosis and countermeasure flow chart
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Check Inv. PCB Screw Connection Condition
Error No.
Error Type
Error Point
Main Reasons
621
Inv. PCB Heatsink
Temperature High
Heatsink Temperature
is Over 90°C
1. Inv. PCB IPM Connection Condition Abnormal
2. Compressor module Fan Motor Operation Abnormal
3. Compressor module Inv. PCB Assembly Defect
4. Overload Operation (Pipe Clogging/ Covering/EEV
Defect/Ref. Overcharge)
Is Installation
Condition Normal?
No
1. Check Pipe Clogging/ Distortion
2. Check Covering (Outdoor/Indoor Unit)
3. Check EEV Connector Assemble Condition/Normal Operation
4. Check Refrigerant Pressure
5. Check Power Wire/ Connection Condition
Reassemble or Manage if abnormality Found
1. Check Inv. PCB Screw Connection Condition
Reassemble or Manage if abnormality Found
No
Inv. PCB IPM Connection
Condition Normal?
Yes
1. Check Compressor module Fan Motor Operation or Lock
Reassemble or Manage if abnormality Found
No
Is ODU Fan Motor Normal?
Yes
1. Reset
Replace Inv. PCB Assembly
No
Is Inv. PCB assembly
Normal?
Yes
Recheck Power and
Installation Condition
Yes
Check Screw Connection Condition