Daikin CTXU25G2V1B User manual

SiBE12-908
Specifications, designs and other content appearing in this brochure are current as of January 2009 but subject to change without notice.
SiBE12-908
Printed in Japan 01/2009 B AK
SiBE12-908
[Applied Models]
 Inverter Multi : Heat Pump
Service Manual / Inverter Multi System with Humidifying G-Series
Preliminary
Inverter Multi System
with Humidifying
G-Series

SiBE12-908
Table of Contents i
Inverter Multi System
with Humidifying
G-Series
zHeat Pump
Indoor Unit
CTXU25G2V1B
CTXU35G2V1B
CTXU42G2V1B
CTXU50G2V1B
Outdoor Unit
2MXU40GV1B
2MXU50GV1B

SiBE12-908
ii Table of Contents

SiBE12-908
Function and Control 1
Part 4
Function and Control
1. Main Functions........................................................................................2
1.1 Frequency Principle..................................................................................2
1.2 Thermostat Control...................................................................................4
1.3 Automatic Operation.................................................................................5
1.4 Programme Dry Function .........................................................................6
1.5 Airflow Direction Control...........................................................................7
1.6 Fan Speed Control for Indoor Units..........................................................8
1.7 HUMID HEAT Operation ..........................................................................9
1.8 Fresh Air Supply Ventilation ...................................................................14
1.9 2-AREA INTELLIGENT EYE ..................................................................16
1.10 Inverter POWERFUL Operation .............................................................18
1.11 ECONO Mode ........................................................................................19
1.12 NIGHT SET Mode ..................................................................................20
1.13 Other Functions......................................................................................21
1.14 Table for Special Modes.........................................................................23
2. Function of Thermistor ..........................................................................25
2.1 Heat Pump Model...................................................................................25
3. Control Specification .............................................................................27
3.1 Mode Hierarchy ......................................................................................27
3.2 Automatic switching for HUMID HEAT operation room..........................28
3.3 Frequency Control..................................................................................29
3.4 Controls at Mode Changing / Start-up....................................................31
3.5 Discharge Pipe Temperature Control.....................................................33
3.6 Input Current Control..............................................................................33
3.7 Freeze-up Protection Control .................................................................34
3.8 Heating Peak-cut Control .......................................................................34
3.9 Fan Control.............................................................................................35
3.10 Liquid Compression Protection Function 2.............................................35
3.11 Defrost Control .......................................................................................36
3.12 Electronic Expansion Valve Control .......................................................37
3.13 Malfunctions ...........................................................................................41
3.14 Forced Operation Mode .........................................................................42
3.15 Additional Function.................................................................................43

Main Functions SiBE12-908
2Function and Control
1. Main Functions
1.1 Frequency Principle
Main Control
Parameters
The compressor is frequency-controlled during normal operation. The target frequency is set by
the following 2 parameters coming from the operating indoor unit:
The load condition of the operating indoor unit
The difference between the room temperature and the set temperature
Additional
Control
Parameters
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 vary
the rotation speed of the compressor. The following table explains the conversion principle:
Drawing of
Inverter
The following drawing shows a schematic view of the inverter principle:
Phase Description
1The supplied AC power source is converted into the DC power source for the present.
2The 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.
50 Hz
60 Hz
Refrigerant circulation rate (high)
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
AC
power
freq=
constant
DC
power
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
high f
low f
freq=variable capacity=
variable
Refrigerant circulation rate (low)
high speed
low speed
(R2812)

SiBE12-908 Main Functions
Function and Control 3
Inverter Features The inverter provides the following features:
The regulating capacity can be changed according to the changes in the outdoor air
temperature and cooling / heating load.
Quick heating and quick cooling
The compressor rotational speed is increased when starting the heating (or cooling). This
enables a quick set temperature.
Even during extreme cold weather, the high capacity is achieved. It is maintained even when
the outdoor air temperature is 2°C.
Comfortable air conditioning
A detailed adjustment is integrated to ensure a fixed room temperature. It is possible to air
condition with a small room temperature variation.
Energy saving heating and cooling
Once the set temperature is reached, the energy saving operation enables to maintain the
room temperature at low power.
Frequency Limits The following table shows the functions that define the minimum and maximum frequency:
Forced Cooling
Operation
For more information, refer to “Forced operation mode” on page 42.
60 120 300
45˚C
Air discharge
temperature
inverter
normal heat pump
Start seconds
(R1187)
Frequency limits Limited during the activation of following functions
Low Four way valve operation compensation. Refer to page 31.
High Discharge pipe temperature control. Refer to page 33.
Input current control. Refer to page 33.
Compressor protection function. Refer to page 32.
Heating peak-cut control. Refer to page 34.
Freeze-up protection control. Refer to page 34.
Defrost control. Refer to page 36.

Main Functions SiBE12-908
4Function and Control
1.2 Thermostat Control
Thermostat control is based on the difference between the room temperature and the set point.
Thermostat OFF Condition
The temperature difference is in the zone A.
Thermostat ON Condition
The temperature difference is above the zone C after being in the zone A.
The system resumes from defrost control in any zones except A.
The operation turns on in any zones except A.
The monitoring time has passed while the temperature difference is in the zone B.
(Cooling / Dry : 10 minutes, Heating : 10 seconds)
Cooling / Dry
Heating
B
A
OFF
ON
C
Cooling : –0.5˚C
Dry : –0.5˚C
Room temperature - set point
Cooling : –2.0˚C
Dry : –2.5~–2.0˚C
(R4668)
B
A
OFF
ON
C
2.0˚C
Room temperature - set point
0.5˚C
(R9424)

SiBE12-908 Main Functions
Function and Control 5
1.3 Automatic Operation
Automatic Cooling / Heating Function
When the AUTO mode is selected with the remote controller, the microcomputer automatically
determines the operation mode from cooling and heating according to the room temperature
and setting temperature at the time of the operation startup, and automatically operates in that
mode.
The unit automatically switches the operation mode to cooling or heating to maintain the room
temperature at the main unit setting temperature.
Detailed
Explanation of
the Function
1. Remote controller setting temperature is set as automatic cooling / heating setting
temperature (18 to 30°C).
2. Main unit setting temperature equals remote controller setting temperature.
3. Mode switching point are as follows.
Heating →Cooling switching point:
Room temperature ≥Main unit setting temperature +3.0 deg.
Cooling →Heating switching point:
Room temperature < Main unit setting temperature –2.5 deg.
Thermostat ON / OFF point is the same as the ON / OFF point of cooling or heating
operation.
4. During initial operation
Room temperature ≥Remote controller setting temperature: Cooling operation
Room temperature < Remote controller setting temperature: Heating operation
Ex: When the set point is 25°C
Cooling Operation →23°C: Thermostat OFF → 22°C: Switch to Heating Operation
Heating Operation → 27°C: Thermostat OFF →28°C: Switch to Cooling Operation
(R9417)
Set point +3.0ºC
Set point –2.0ºC
=Thermostat OFF
Set point +2.0ºC
=Thermostat OFF
Heating Operation
Set point –2.5ºC
Cooling Operation

Main Functions SiBE12-908
6Function and Control
1.4 Programme Dry Function
Programme dry function removes humidity while preventing the room temperature from
lowering.
Since the microcomputer controls both the temperature and airflow volume, the temperature
adjustment and fan adjustment buttons are inoperable in this mode.
In Case of
Inverter Units
The microcomputer automatically sets the temperature and fan settings. The difference
between the room temperature at startup and the temperature set by the microcomputer is
divided into two zones. Then, the unit operates in the dry mode with an appropriate capacity for
each zone to maintain the temperature and humidity at a comfortable level.
Room temperature at
startup
Set temperature
X
Thermostat OFF point
Y
Thermostat ON point
Z
24ºC or more
Room temperature at
startup
X –2.5ºC
X –0.5ºC
or
Y + 0.5ºC (zone B)
continues for 10 min.
23.5ºC
X –2.0ºC
X –0.5ºC
or
Y + 0.5ºC (zone B)
continues for 10 min.
~
18ºC
18ºC X –2.0ºC
X –0.5ºC = 17.5ºC
or
Y + 0.5ºC (zone B)
continues for 10 min.
17.5ºC
~
Z
Y
Zone B Zone B
Zone A = Thermostat OFF
Zone C = Thermostat ON
+0.5ºC
(R6841)

SiBE12-908 Main Functions
Function and Control 7
1.5 Airflow Direction Control
Power-Airflow
Dual Flaps
The large flaps send a large volume of air downwards to the floor. The flap provides an optimum
control area in cooling, heating, and dry mode.
Heating Mode
During heating mode, the large flap enables direct warm air straight downwards. The flap
presses the warm air above the floor to reach the entire room.
Cooling / Dry Mode
During cooling or dry mode, the flap retracts into the indoor unit. Then, cool air can be blown far
and pervaded all over the room.
Wide-Angle
Louvres
The louvres, made of elastic synthetic resin, provide a wide range of airflow that guarantees a
comfortable air distribution.
Auto-Swing The following table explains the auto swing process for heating, cooling, dry, and fan :
3-D Airflow Alternative repetition of vertical and horizontal swing motions enables uniform air-
conditioning of the entire room. This function is effective for starting the air conditioner.
When the horizontal swing and vertical swing are both set to auto mode, the airflow become
3-D airflow and the horizontal swing and vertical swing motions are alternated. The order of
swing motion is such that it turns counterclockwise, starting from the right upper point as
viewed to the front side of the indoor unit.
COMFORT
AIRFLOW
The vertical swing flap is controlled not to blow the air directly on the person in the room.
Vertical Swing (up and down) Horizontal Swing
(right and left:
automatic)
Cooling / Dry Heating Fan
15˚
50˚
30˚
55˚
(R8315) (R8316)
30˚
70˚
30˚
65˚
(R8317)
5˚
80˚
30˚ 65˚
(R8318)
45˚
45˚


(R1024)
Heating Cooling
(R8413)
80°
(R4302)
5°