Check
SiUS342303E
379
Part 6 Service Diagnosis
4.6 Refrigerant Shortage Check
CHECK 7
In case of
VRV
Systems, the only way to judge as the shortage of refrigerant is with operating
conditions due to the relationship to pressure control and electronic expansion valve control.
As information for making a judgement, refer to the information below.
Diagnosis of shortage of refrigerant
1. The superheating degree of suction gas rises. Consequently, the compressor discharge gas
temperature becomes higher.
2. The superheating degree of suction gas rises. Consequently, the electronic expansion valve
turns open.
3. Low pressure drops to cause the unit not to demonstrate cooling/heating capacity.
Cooling
High pressure
Low pressure
Frequency
The opening degree of the indoor unit
electronic expansion valve becomes
larger.
Either of the electronic expansion
valves becomes fully open.
Frequency comes to the minimum level.
Fan control is activated for high
pressure protection under
cooling control at low outdoor
air temperature, i.e., the fan is
hunting at high pressure.
High pressure drops
with decrease in
compressor capacity.
If frequency comes to the
minimum level, low
pressure cannot be
maintained.
Low pressure rises as the
opening degree of the indoor
unit electronic expansion
valve becomes larger.
Frequency slightly increases
under the capacity control.
To maintain low
pressure,
frequency drops
due to the
capacity control.
Heating
High pressure
Low pressure
Frequency
The opening degree of the outdoor unit electronic expansion valve becomes larger.
The outdoor unit electronic expansion valve fully opens and frequency increases.
Discharge pipe or low pressure dropping control
(High pressure
is maintained at
a constant
level.)
To maintain low pressure,
frequency drops due to the
capacity control.
Frequency drops
due to the dropping
control.
(Degree of refrigerant shortage)
Higher degree of shortage
Proper amount
(Low pressure
is maintained at
a constant
level.)
Frequency comes to
the minimum level.
Summary of Contents for VRV EMERION RXYQ-AATJA
Page 1: ...Service Manual Heat Pump 60 Hz RXYQ AATJA 208 230 V RXYQ AAYDA 460 V SiUS342303E...
Page 410: ...Wiring Diagrams SiUS342303E 403 Part 7 Appendix FXEQ07 09 12 15 18 24PVJU 3D098557A...
Page 411: ...SiUS342303E Wiring Diagrams Part 7 Appendix 404 FXDQ07 09 12 18 24MVJU C 3D050501C...
Page 416: ...Wiring Diagrams SiUS342303E 409 Part 7 Appendix FXHQ12 24 36MVJU 3D048116C...
Page 417: ...SiUS342303E Wiring Diagrams Part 7 Appendix 410 FXAQ07 09 12 18 24PVJU 3D075354F...
Page 424: ...Wiring Diagrams SiUS342303E 417 Part 7 Appendix VAM1200GVJU 3D073270D...
