Service Manual
Table Of Contents
- Cover
- Table of contents
- Part 1 List of Functions
- Part 2 Specifications
- Part 3 Printed Circuit Board Connector Wiring Diagram
- Part 4 Refrigerant Circuit
- Part 5 Functions and Control
- Part 6 Test Operation and Field Settings
- Part 7 Remote Controller
- Part 8 Troubleshooting
- 1. Troubleshooting with LED
- 2. Service Diagnosis
- 3. Error Codes and Description
- 4. Troubleshooting for CTXG, CTXS, FTXS, CDXS, FDXS, FVXS Series
- 5. Troubleshooting for FFQ Series
- 6. Troubleshooting for Branch Provider (BP) Unit
- 7. Troubleshooting for Outdoor Unit
- 8. Thermistor Resistance/Temperature Characteristics
- 9. Pressure Sensor
- 10. Method of Replacing Inverter’s Power Transistors Modules
- Part 9 Appendix
SiUS181631EA Protection Control
Functions and Control 65
4.5 Freeze-up Protection Control
Outline According to the freeze prevention status sent from the BP unit, the compressor output frequency is
regulated to decrease compressor capacity in order to prevent the indoor heat exchanger from
freezing.
Details Zones are divided based on the freeze prevention status signal sent from the BP unit (indoor unit),
and the freeze prevention control prevents freezing of the indoor unit.
Recovery zone: Lift the control
Increase zone: 1 step up / 60 sec.
Keep zone: Frequency is not controlled
Decrease zone: 1 step down / 60 sec.
Stop zone: Thermostat-OFF (only the target indoor unit)
The temperature in the above figure depends on the model (reference value).
˚C
13
7
5
3
0
˚F
55.4
44.6
41
37.4
32
Recovery zone
Increase zone
Keep zone
Decrease zone
(R19085)
Indoor heat exchanger
temperature