![background image](http://html2.mh-extra.com/html/daikin/vrv-iii-reyq8py1b/vrv-iii-reyq8py1b_service-manual_3517540389.webp)
Troubleshooting (OP: Unified ON/OFF Controller)
SiBE37-701
378
Troubleshooting
[Check 11] Check for overcharge of refrigerant.
In case of VRV Systems, the only way to judge as the overcharge of refrigerant is with operating
conditions due to the relationship to pressure control and electronic expansion valve control.
As information for making a judgment, refer to information provided below.
Diagnosis of overcharge of refrigerant
1. High pressure rises. Consequently, overload control is exercised to cause scant cooling
capacity.
2. The superheated degree of suction gas lowers (or the wet operation is performed).
Consequently, the compressor becomes lower in discharge pipe temperature despite of
pressure loads.
3. The supercooled degree of condensate rises. Consequently, in heating operation, the
temperature of outlet air passing through the supercooled section becomes lower.
Cooling
High pressure
Low pressure
Frequency
High-pressure
drooping control
(LP is maintained
at a constant level.)
To maintain LP, frequency
increases under the capacity
control.
HP gradually rises
with increase in
frequency.
Frequency comes to
the minimum level.
Supercooled degree
becomes higher.
(Liquid connection
pipe temperature
lowers.)
LP rises due to
reduced compressor
output.
High pressure
Low pressure
Frequency
Heating
The outdoor unit motorized valve is
closed due to the overload control.
Frequency comes to
the minimum level.
(HP is maintained
at a constant level.)
LP rises due to
reduced frequency.
To maintain HP, frequency reduces
under the capacity control.
HP drops or rises immediately
after the overload control is
complete.
LP drops due to closed
outdoor unit motorized
valve.
Hot gas bypass is activated
for LP protection, i.e.,
hunting at LP.
Higher degree of overcharge
(Degree of overcharge)
Proper quantity
Summary of Contents for VRV III REYQ8PY1B
Page 1: ...REYQ8 48PY1B R 410A Heat Recovery 50Hz SiBE37 701...
Page 111: ...Refrigerant Flow for Each Operation Mode SiBE37 701 100 Refrigerant Circuit...
Page 252: ...SiBE37 701 Troubleshooting by Remote Controller Troubleshooting 241...
Page 396: ...SiBE37 701 Piping Diagrams Appendix 385 REYQ14P 16P 3D058153B S2NPL S1NPH...
Page 397: ...Piping Diagrams SiBE37 701 386 Appendix REMQ8P 3D057743...
Page 398: ...SiBE37 701 Piping Diagrams Appendix 387 REMQ10P 12P 3D057742...
Page 399: ...Piping Diagrams SiBE37 701 388 Appendix REMQ14P 16P 3D057741...
Page 400: ...SiBE37 701 Piping Diagrams Appendix 389 1 2 Indoor Unit FXFQ P...
Page 405: ...Piping Diagrams SiBE37 701 394 Appendix 1 3 BS Unit 4D057985A...
Page 415: ...Wiring Diagrams for Reference SiBE37 701 404 Appendix FXZQ20M 25M 32M 40M 50MV1...
Page 416: ...SiBE37 701 Wiring Diagrams for Reference Appendix 405 FXCQ20M 25M 32M 63MV3...
Page 417: ...Wiring Diagrams for Reference SiBE37 701 406 Appendix FXCQ40M 50M 80M 125MV3...
Page 420: ...SiBE37 701 Wiring Diagrams for Reference Appendix 409 FXDQ20M 25MV3...
Page 421: ...Wiring Diagrams for Reference SiBE37 701 410 Appendix FXSQ20M 25M 32M 40M 50M 63MV3...
Page 422: ...SiBE37 701 Wiring Diagrams for Reference Appendix 411 FXSQ80M 100M 125MV3...
Page 447: ...Example of connection SiBE37 701 436 Appendix...
Page 453: ...Method of Checking the Inverter s Power Transistors and Diode Modules SiBE37 701 442 Appendix...
Page 467: ...SiBE37 701 iv Index...