Main Functions; Temperature Control; Frequency Principle - Daikin FFQ09Q2VJUFFQ12Q2VJUFFQ15Q2VJUFFQ18Q2VJURX09QMVJURX12QMVJURX15QMVJURX18QMVJU Service Manual

Main Functions

1. Main Functions

1.1

Temperature Control

Definitions of The definitions of temperatures are classified as following.
Temperatures
Temperature 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
Control
of lower part of the room, depending on the installation condition. Practically, 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 The frequency of the compressor is controlled by the following 2 parameters:
Parameters
The target frequency is adapted by additional parameters in the following cases:
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 following table explains the inverter principle:
Phase
13
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
Room temperature
The load condition of the operating indoor unit
The difference between the room thermistor temperature and the target temperature
Frequency restrictions
Initial settings
Forced cooling operation
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 increase of refrigerant circulation. This leads to a larger amount of heat exchange
per unit.
When the frequency decreases, the rotation speed of the compressor decreases
resulting in a decrease of refrigerant circulation. This leads to a smaller amount of heat
exchange per unit.
Room thermistor temperature
Description
SiUS091628EA
Target temperature
Set temperature
(R24366)
Functions and Control