Compressor Pi Control - Daikin VRV IV-S RXTQ-TAVJU Series Service Manual

SiUS331604E
2.2

Compressor PI Control

Carries out compressor capacity control to maintain Te at constant during cooling operation and Tc at constant
during heating operation thus ensuring stable unit performance.
Cooling operation
Controls compressor capacity to achieve target Te value (TeS).
Te: Low pressure equivalent saturation temperature
TeS: Target temperature of Te (Varies depending on Te setting, operating frequency, etc.)
(1) VRT control (Default)
When the required capacity of all indoor units (suction air temperature – set temperature) is small, the target
evaporation temperature is further increased in order to adjust capacity. From the outdoor unit side, the
temperature difference for all indoor units (∆T) is confirmed, and the target temperature is changed.
(2) Constant pressure control
The target evaporation temperature is not changed.
Te setting (Make this setting while in setting mode 2.)
Lower
3°C
(37.4°F)
Heating operation
Controls compressor capacity to achieve target Tc value (TcS).
Tc: High pressure equivalent saturation temperature
TcS: Target temperature of Tc (Varies depending on Tc setting, operating frequency, etc.)
(1) VRT control (Default)
When the required capacity of all indoor units (set temperature – suction air temperature) is small, the target
condensation temperature is further decreased in order to adjust capacity. From the outdoor unit side, the
temperature difference for all indoor units (∆T) is confirmed, and the target temperature is changed.
(2) Constant pressure control
The target condensation temperature is not changed.
Tc setting (Make this setting while in setting mode 2.)
VRT
(Default)
Variable
Functions and Control
VRT
Normal
(Default)
6°C
Variable
(42.8°F)
Normal
(114.8°F)
8°C 9°C
(46.4°F) (48.2°F)
46°C
Higher
10°C
(50°F) (51.8°F)
Higher
52°C
(125.6°F)
Basic Control
11°C
34