SiBE37-701
Troubleshooting (OP: Unified ON/OFF Controller)
Troubleshooting
373
[CHECK 6] Check for causes of drop in low pressure
Referring to the Fault Tree Analysis (FTA) shown below, probe the faulty points.
Abnormally low
low-pressure
(Low evaporating
temperature)
[In cooling]
(See *1.)
Faulty low
pressure
control
Faulty
compressor
capacity
control
Faulty low pressure sensor
←
Are the electrical characteristics normal?
Faulty control PC board
←
Is the pressure value checked with the Service Checker
corresponding to the measurement of the pressure sensor?
Faulty low
pressure
protection
control
Faulty low pressure sensor
←
Are the electrical characteristics normal?
Faulty hot gas solenoid valve
←
Are the coil resistance and insulation normal?
Faulty control PC board
←
Is the pressure value checked with the Service Checker
corresponding to the measurement of the pressure sensor?
[In both cooling
and heating]
(See *2.)
[In cooling]
If the indoor unit
electronic
expansion valve is
throttled too much:
(See *3.)
Faulty indoor
unit electronic
expansion valve
Faulty valve coil
Faulty valve body
←
Are the coil resistance and insulation normal?
Faulty
control
Faulty gas pipe
thermistor of indoor unit
Faulty liquid pipe thermistor
of indoor unit
Faulty control PC board
←
Check for the thermistor resistance and connection.
←
Check for the thermistor resistance and connection.
←
Is the pressure value checked with the Service Checker
corresponding to the measurement of the pressure sensor?
Faulty outdoor
unit electronic
expansion valve
Faulty valve coil
Faulty valve body
←
Are the coil resistance and insulation
normal?
[In heating]
If the outdoor unit
electronic
expansion valve
excessively
throttled:
(See *4.)
Faulty
control
Faulty low pressure sensor
Faulty suction pipe thermistor
Faulty control PC board
←
Are the electrical characteristics normal?
←
Check for the thermistor resistance and
connection.
[In cooling]
Low suction
air temperature
of the
evaporator
[In heating]
Low suction air
temperature of
indoor unit
Short circuit
←
Is the suction air temperature not less than 14˚C
←
Is the indoor temperature not more than 14˚C
Low ambient temperature
Faulty suction air thermistor of indoor unit
←
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
Low suction air temperature of outdoor unit
←
Is the outdoor temperature not less than -20˚C
Faulty outdoor temperature thermistor of outdoor unit
←
Is the connector properly connected?
Are the thermistor resistance characteristics normal?
High pipe
resistance
Abnormal piping length
Bent or crashed pipe
Clogging of foreign particles
Stop valve closed
←
Does the piping length fall in the permissible range?
←
Conduct visual checks for pipe conditions.
←
Is there any temperature difference caused before
and after the filter or branch pipe?
←
Check to be sure the stop valve is open.
Less
circulation
quantity of
refrigerant
Degradation
in condensing
capacity
Inadequate refrigerant quantity
←
Moisture choke
←
Eliminate moisture by vacuum operation.
Dirty
evaporator
Decreased
fan airflow
rate
Decreased
fan output
Faulty fan motor
←
Can the fan motor be rotated with hands?
Are the motor coil resistance and insulation normal?
←
Is the heat exchanger clogged?
Faulty control PC board
(Including capacity setting)
←
If a spare PC board is mounted, is the capacity
setting properly made?
High air
passage
resistance
Dirty filter
←
Is there any obstacle in the air passage?
←
Is the air filter clogged?
Obstacle
*1: For details of the compressor capacity control while in cooling, refer to “Compressor PI Control” on P106.
*2: The “low pressure protection control” includes low pressure protection control and hot gas bypass control. For details, refer to P132.
*3: In cooling, the indoor unit electronic expansion valve is used for “superheated degree control”. (For details, refer to P147.)
*4: In heating, the outdoor unit electronic expansion valve (EVM) is used for “superheated degree control of outdoor unit heat exchanger”.
(For details, refer to P114.)
Faulty electronic
expansion valve
control
SDK04009
Summary of Contents for VRV III REYQ10PY1B
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 ...