Friedrich MD24Y3J Svc Manual page 58

Display
Title
code
22 Max. C/T
WARNING
Before checking PCB or each outdoor electric parts, wait for 3 minutes after the power is off. When measuring at standby state
of power supply, after checking the measurement mode of the meter, be careful of the short-circuits with other parts.
n Error Diagnosis and Countermeasure Flow Chart
Is installation
condition normal?
Yes
Are the resistance
Between each phase and
insulation resistance of Inverter
compressor normal?
Yes
Is compressor
Wire connection
condition normal?
Yes
Is inverter PCB assembly
power connection normal?
Yes
Is input voltage normal?
Yes
Is inverter PCB assembly
normal?
Yes
Recheck power and installation condition
Only for training and service purposes
Cause of error
• Input Over Current
1. Check Pipe clogging/distortion
2. Check Covering (Indoor/Outdoor Unit)
No
3. Check EEV connector assemble condition/normal
operation
4. Check refrigerant pressure
→ Reassemble or manage if abnormality found
1. Check resistance between each terminal of compressor
2. Check insulation resistance between compressor
No
terminal and pipe
→ Replace compressor if abnormality found
1. Check inverter PCB assembly U,V,W connector
connection condition
2. Check wire disconnection and wiring
No
3. Check compressor terminal connection condition
(bad contact)
→ Reassemble if abnormality found
Check connection between inverter PCB assembly and
No
bridge diode(misconnection, disconnection)
→ wiring again if abnormality found
No Check
L~N phase is 230V 15%
→ Check connection condition and wiring if power is
abnormal
No
Check inverter PCB assembly IPM normality
→ Replace inverter PCB assembly
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Check point & Normal condition
• Malfunction of compressor
• Blocking of pipe
• Low voltage input
• Refrigerant, pipe length, blocked, ...