Service manual
Service Manual SM-MDS_(i) 69
E8
General system failure
• High pressure malfunction occur 3 times within 1 hour
- outdoor unit motor broken (cooling)
- outdoor circulating air short (cooling)
- outdoor heat exchanger too dirty (cooling)
- outdoor ball valve not open
- indoor circulating air short (heating)
- indoor heat exchanger too dirty (heating)
- indoor unit filter web blocked (heating)
- indoor unit EXV not turn on properly (heating)
- too much refrigerant
- outdoor unit PCB high pressure output port malfunction
- pressure sensor broken
- pressure switch broken
• Low pressure malfunction occur 3 times within 1 hour
- outdoor ball valve not open
- refrigerant leakage or shortage
- outdoor unit PCB low pressure output port malfunction
- low pressure sensor broken
• Too high discharge temperature occur once
- outdoor unit motor broken (cooling)
- outdoor circulating air short (cooling)
- outdoor heat exchanger too dirty (cooling)
- outdoor unit EXV not turn on properly (heating)
- indoor unit EXV not turn on properly
- refrigerant leakage or shortage
- outdoor ball valve not open
• Compressor overload protector shut and occurs 3 times
- too much current flow in the compressor
- compressor overload protector protecting value wrongly set
80
H1
High pressure trip
• 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
H2
Digital scroll
compressor overload
• Digital compressor operating current too high, overload protector on
H3
Fixed scroll compressor
overload
• Fixed scroll compressor operating current too high, overload protector on
77
L1
Low pressure trip
• 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