McQuay MDS 100B User Manual

Service Manual SM-MDS_(ii) 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
77
H3
Fixed scroll compressor
overload
 Fixed scroll compressor operating current too high, overload protector on
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

McQuay MDS 100B Specifications

General

Brand	McQuay
Model	MDS 100B
Category	Compressor
Language	English