Service manual
Service Manual SM-MDS_(i) 65
FE
Master unit and slave
unit communication
malfunction
• Master unit and slave unit communication wire reversed
• Master unit and slave unit communication wire broken or loose
• Slave unit toggle switch set wrongly
• Master and slave unit PCB version conflict / different
79
H0
Digital compressor
overloaded
• Digital compressor operating current too high, overload protector OL4 on
H1
Fixed compressor 1
overloaded
• Fixed compressor 1 operating current too high, overload protector OL1 on
H2
Fixed compressor 2
overloaded
• Fixed compressor 2 operating current too high, overload protector OL2 on
H3
Fixed compressor 3
overloaded
• Fixed compressor 3 operating current too high, overload protector OL3 on
77
H4
High pressure too high
• Outdoor motor broken (cooling)
• Outdoor circulating air short-circuit (cooling)
• Outdoor heat exchanger too dirty (cooling)
• Outdoor ball valve not open
• Indoor circulating air short-circuit (heating)
• Indoor heat exchanger too dirty (heating)
• Indoor unit filter blocked by dirt (heating)
• Indoor EXV not on properly (heating)
• Refrigerant over charged
• Outdoor PCB high pressure output port abnormal
• Pressure sensor broken
• Pressure switch broken
78
H5
High pressure sensor
malfunction
• High pressure sensor communication wire broken
• Outdoor PCB HS port broken
74
H6
Discharge temperature
too high (TH1)
• Outdoor motor broken (cooling)
• Outdoor circulation air short-circuit (cooling)
• Outdoor heat exchanger too dirty (cooling)
• Outdoor EXV not on properly (heating)
• Indoor EXV not on properly (heating)
• Refrigerant leakage or insufficient
• Outdoor ball valve not open
78
L0
Super heat protecting
value too small
• Indoor motor not work when cooling
• Indoor EXV opening degree abnormal when cooling
• Outdoor motor not work when heating
• Outdoor EXV opening degree abnormal when heating
• Low pressure sensor abnormal
• Refrigerant over charged
86
L1
Low pressure too low
• Outdoor ball valve not open
• Outdoor heat exchanger efficiency too low when heating
• Outdoor motor run abnormally when heating
• Refrigerant leakage or insufficient
• Outdoor PCB low pressure output port abnormal
• Low pressure sensor broken
78
6