Normal Operation; List Of Functions In Normal Operation; Compressor Control - Daikin RXQ12AHR Service Manual

SiAF341904E

5. Normal Operation

5.1

List of Functions in Normal Operation

Pc : High pressure sensor detection value
Pe : Low pressure sensor detection value
Part Name
Inverter compressor 1
Inverter compressor 2
Inverter fan 1
Inverter fan 2
Electronic expansion valve
(Injection)
Electronic expansion valve
(Refrigerant auto charge)
Solenoid valve (Oil return 1)
Solenoid valve (Oil return 2)
: equipped
—: not equipped
5.2

Compressor Control

In order to provide a steady capacity, the compressor capacity is controlled to achieve
temperature Te during cooling operation.
During cooling operation
The compressor capacity is controlled so Te approaches TeS (target value of temperature).
1. VRTsmart Control
 When all the connected indoor units are VRTsmart control applicable models
Applicable models: FXFSQ-AR, FXMQ-PB
The required capacity is calculated based on the operation condition of each individual indoor
unit and this data is transmitted to the outdoor unit. The outdoor unit adjusts the refrigerant
temperature of the whole system to an adequate value according to the indoor unit that needs
the most capacity.
In case of target evaporation temperature adjustment, first the capacity is adjusted by changing
the indoor unit airflow to L tap. If the capacity is still too much, the target evaporation
temperature is elevated further to adjust.
2. VRT Control
 When one or more of the connected indoor units are not VRTsmart control applicable
If the required capacity becomes low in all indoor units (Room temperature Th1 – set
temperature), the target evaporation temperature is elevated further to adjust. In the outdoor
unit, the difference of temperature (∆T) in all indoor units is checked and the set temperature is
changed. Unlike VRTsmart control, there is no airflow control of the indoor units.
3. Te fix Control
The target evaporation temperature is not changed.
Te value (Set in mode 2-8)
Standard (Factory
Te: Low pressure equivalent saturation temperature (°C)
TeS: Te target value (varies according to Te setting, compressor operation frequency, etc.)
Part 4 Functions and Control
Electric
RXQ6-12A
Symbol
M1C

M2C —
M1F

M2F —
Y2E

Y4E

Y3S

Y4S —
models
setting)
6 7
RXQ14A RXQ16-20A
 
—

 
 
 
 
 
—

High
8 9
Normal Operation
Function of Functional Part
PI control by Te target.
Fan speed 10 steps to keep
minimum Tc target 34°C.
0-480 pulse at compressor on
Minimum pulse
Only close if Pc – Pe < 0.3 MPa
(when compressor off)
10 11
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