Friedrich MD24Y3J Svc Manual page 87

Display
Title
code
AC input instant over cur-
rent error
73
(Matter of software)
n Error Diagnosis and Countermeasure Flow Chart
Is installation
condition normal?
Yes
Is input voltage normal?
Yes
Is AC input Wire connection
condition normal?
Yes
Is compressor
Wire connection
condition normal?
Yes
Is inverter PCB assembly
normal?
Yes
Recheck power and
installation condition
Only for training and service purposes
Cause of error
Inverter PCB input power
current is over 48A(peak)
for 2ms
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
Check
No
L~N phase voltage is 230V ± 15%
→ Check connection condition and wiring if power is abnormal
1.Check L,N connection condition
No
2.Check wire disconnection and wiring
→ Reassemble if abnormality found
1.Check inverter PCB assembly U,V,W connector connection condition
No
2.Check wire disconnection and wiring
3.Check compressor terminal connection condition(bad contact)
→ Reassemble if abnormality found
No
Check inverter PCB assembly IPM normality
→ Replace inverter PCB assembly
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Check point & Normal condition
1. Overload operation (Pipe clogging/Covering/EEV
defect/Ref.overcharge)
2. Compressor damage
(Insulation damage/Motor damage)
3. Input voltage abnormal (L, N)
4. Power line assemble condition abnormal
5. Inverter PCB assembly damage
(input current sensing part)