Main Functions; Temperature Control; Frequency Principle - Daikin BA-Series 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
Control
temperature of lower part of the room, depending on the type of the indoor unit or 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

Main Control The frequency of the compressor is controlled by the following 2 parameters:
Parameters
Additional The target frequency is adapted by additional parameters in the following cases:
Control
Parameters
Inverter Principle To regulate the capacity, a frequency control is needed. The inverter makes it possible to alter
the rotation speed of the compressor. The following table explains the conversion principle:
27
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 illustration is for wall mounted type as representative.
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
Phase
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
SiBE05-722ED
Target temperature
Set temperature
(R12321)
Function and Control