Compressor Control - Daikin VRV RXYMQ-A Series Service Manual

SiME332106E
5.2

Compressor Control

In order to provide a steady capacity, the compressor capacity is controlled to achieve
temperature Te (or Tc) during cooling (or heating) operation.
During cooling (or heating) operation
The compressor capacity is controlled so Te (or Tc) approaches TeS (or TcS) (target value of
temperature).
1. VRTsmart Control
 When all the connected indoor units are VRTsmart control applicable models
Applicable models: FXFSQ-AR, FXDQ-PD, FXDQ-ND, FXMQ-PB, FXAQ-AR
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 (or condensation) 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 (or condensation) 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 (or high) in all indoor units (Room temperature Th1 - set
temperature), the target evaporation (or condensation) 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 (for cooling)
The target evaporation temperature is not changed.
Te value (Set in mode 2-8)
Te: Low pressure equivalent saturation temperature (°C)
TeS: Te target value (varies according to Te setting, compressor operation frequency, etc.)
4. Tc fix Control (for heating)
The target condensation temperature is not changed.
Tc value (Set in mode 2-9)
Tc: High pressure equivalent saturation temperature
TcS: Tc target value (varies according to Tc setting)
Part 4 Functions and Control
models
Standard
(Factory setting)
6 7
Low Standard
41 43
High
8 9
High
(Factory setting)
46
Normal Control
10 11
55