Specifications
Table Of Contents
- Cover
- Table of Contents
- Part 1 General Information
- Part 2 Specifications
- Part 3 Refrigerant Circuit
- Part 4 Function
- Part 5 Test Operation
- Part 6 Troubleshooting
- Part 7 Appendix
- 1. Piping Diagrams
- 2. Wiring Diagrams for Reference
- 3. List of Electrical and Functional Parts
- 4. Option List
- 5. Piping Installation Point
- 6. Example of connection (R-410A Type)
- 7. Thermistor Resistance / Temperature Characteristics
- 8. Pressure Sensor
- 9. Method of Checking the Inverter’s Power Transistors and Diode Modules
- Part 8 Precautions for New Refrigerant (R-410A)
- Index
- Drawings & Flow Charts

Troubleshooting (OP: Unified ON/OFF Controller) Si34-704
304 Troubleshooting
[CHECK 1] Check on connector of fan motor (Power supply cable)
(1) Turn off the power supply.
Measure the resistance between phases of U,V,W at the motor side connectors (three-core
wire) to check that the values are balanced and there is no short circuiting, while connector
or relay connector is disconnected.
[CHECK 2] (1) Turn off the power supply.
(2) Measure the resistance between Vcc and each phase of U,V,W, and GND and each phase
at the motor side connectors (five-core wire) to check that the values are balanced within the
range of ± 20 %, while connector or relay connector is disconnected.
Furthermore, to use a multiple meter for measurement, connect the probe of negative pole
to Vcc and that of positive pole to GND.
Red
White
Black
U
V
W
Measure the resistance
values between phases
U,V,W.
5 Gray
4 Pink
3 Orange
2 Blue
1 Yellow
GND
Vcc
W
V
U
Measure the resistance
values between Vcc
and U,V,W, and GND
and U,V,W.