SiUS041829E
Main Functions
Part 4 Functions and Control
23
1. Main Functions
1.1 Temperature Control
Definitions of
Temperatures
The definitions of temperatures are classified as following.
Room temperature: temperature of lower part of the room
Set temperature: temperature set by remote controller
Room thermistor temperature: temperature detected by room temperature thermistor
Target temperature: temperature determined by microcomputer
Temperature
Control
The temperature of the room is detected by the room temperature thermistor. However, there is a
difference between the temperature detected by room temperature thermistor and the temperature
of lower part of the room, depending on the type of the indoor unit or installation condition. In
practice, the temperature control is done by the target temperature appropriately adjusted for the
indoor unit and the temperature detected by room temperature thermistor.
1.2 Frequency Principle
Control
Parameters
The frequency of the compressor is controlled by the following 2 parameters:
The load condition of the operating indoor unit
The difference between the room thermistor temperature and the target temperature
The target frequency is adapted by additional parameters in the following cases:
Frequency restrictions
Initial settings
Forced cooling operation
Inverter Principle
To regulate the capacity, a frequency control is needed. The inverter makes it possible to control
the rotation speed of the compressor. The followings explain the inverter principle:
Phase 1
The supplied AC power source is converted into the DC power source for the present.
Phase 2
The DC power source is reconverted into the three phase AC power source with variable
frequency.
When the frequency increases, the rotation speed of the compressor increases resulting in an
increase of refrigerant circulation. This leads to a larger amount of heat exchange per unit.
Target temperature
Set temperature
Room temperature
Room thermistor temperature
(R12321)
Summary of Contents for RX09RMVJU9
Page 17: ...SiUS041829E Part 2 Specifications 13 1 Specifications 14 Part 2 Specifications ...
Page 125: ...SiUS041829E Check Part 6 Service Diagnosis 121 18 class R25105 1 2 3 4 Multimeter ...
Page 127: ...SiUS041829E Check Part 6 Service Diagnosis 123 18 class R20704 W V U DC_P1 DC_N1 ...
Page 143: ...SiUS041829E Operation Limit Part 8 Appendix 139 4 Operation Limit RX09 12 18RMVJU9 3D092209E ...
