Main Functions; Frequency Principle - Daikin FTXL20G2V1B Service Manual

Main Functions

1. Main Functions

Note: The definitions of temperatures are classified as following.
Š Room temperature: temperature of the lower part of the room
Š Set temperature: temperature set by remote control
Š Room thermistor temperature: temperature detected by room temperature thermistor
Š Target temperature: temperature determined by microcomputer
1.1

Frequency Principle

Main Control
The compressor is frequency-controlled during normal operation. The target frequency is set by
the following 2 parameters coming from the operating indoor unit:
Parameters
„ The load condition of the operating indoor unit
„ The difference between the room thermistor temperature and the target temperature
Additional
The target frequency is adapted by additional parameters in the following cases:
„ Frequency restrictions
Control
„ Initial settings
Parameters
„ Forced cooling operation
Inverter Principle To regulate the capacity, a frequency control is needed. The inverter makes it possible to vary
the rotation speed of the compressor. The following table explains the conversion principle:
Phase
20
Room temperature
1 The supplied AC power source is converted into the DC power source for the present.
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 increased refrigerant circulation. This leads to a higher amount of the heat
exchange per unit.
„ When the frequency decreases, the rotation speed of the compressor decreases
resulting in a decreased refrigerant circulation. This leads to a lower amount of the heat
exchange per unit.
Room thermistor temperature
Description
SiENBE04-925_A
Target temperature
Set temperature
(R12321)
Function and Control