Daikin R407C PLUS - Page 91

Outline of Control (Outdoor Unit) < Symbols using in this manual > Si33-105
80 Function R407C PLUS Series Heat Recovery System
3.5.6 Low Outside Temperature Cooling Control
Controls the outdoor unit fans and compressors to prevent refrigerant circulation from
decreasing due to lowering of high pressure and to maintain high pressure when the outside
temperature is low during cooling operation.
!
When the outdoor temperature is 5°C or lower and Pc<8.0k (Tc<20.0 °C) during cooling
operation, starts low outdoor temperature cooling control from Step 3-1 (Fan tap : Step ).
(Does not pass through low outdoor temperature cooling step -1)
Fan
Compressor
16/18/20 class
H+ON/ON+ON
Normal operation
24/26/28/30 class
H+ON+ON
+ON/ON+ON
HP < 1.05MPa
continues for 30 sec
HP > 1.58MPa
continues for 30 sec
Condition A
Fan
Compressor
16/18/20 class
H+OFF/ON+OFF
Upper limit 71 Hz +OFF
(Constant Te control)
24/26/28/30 class
H+OFF+ON
+OFF/ON+OFF
Upper limit 52 Hz+ON+OFF
(Constant Te control)
HP < 1.05MPa
continues for 30 sec
HP > 1.58MPa
continues for 30 sec
Condition A
(V0819)
Condition A
• HP < 0.78MPa
• Ta < 5˚C
(Outdoor air temp.)
Step 1-1
Fan
Compressor
16/18/20 class
H+OFF/OFF+OFF
Upper limit 71 Hz+OFF
(Constant Te control) However,
decrease
the target temp. for 5˚C
24/26/28/30 class
H+OFF+OFF
+OFF/OFF+OFF
Upper limit 52 Hz +ON+OFF
(Constant Te control) However,
decrease
the target temp. for 5˚C
HP < 1.05MPa
continues for 30 sec
HP > 1.58MPa
continues for 30 sec
Condition A
Step 1-2
Fan
Compressor
16/18/20 class
L+OFF/OFF+OFF
41~ 71 Hz+OFF
(Constant Te control) However,
decrease
the target temp. for 5˚C
24/26/28/30 class
L+OFF+OFF
+OFF/OFF+OFF
41~ 52 Hz+ON(OFF)+OFF
(Constant Te control) However,
decrease
the target temp. for 5˚C
HP > 1.7 MPa
Condition A
Step 1-3
Fan
Compressor
16/18/20 class
L+OFF/OFF+OFF
Upper limit 41 Hz
+OFF
24/26/28/30 class
L+OFF+OFF
+OFF/OFF+OFF
Upper limit 41 Hz
+OFF+OFF
Condition A
Step 3-1
Fan
Compressor
16/18/20 class
OFF+OFF/
OFF+OFF
Upper limit 41 Hz
+OFF
24/26/28/30 class
OFF+OFF+OFF
+OFF/OFF+OFF
Upper limit 41 Hz
+OFF+OFF
Step 3-2
• HP < 0.78MPa
• Tfin < 67 ˚C
H Tfin Inverter fin
temperature
(
&
• HP > 1.70MPa
• Tfin > 87 ˚C
(
OR
HP > 2.16MPa
HP > 2.16MPa
HP > 2.16MPa
HP > 2.16MPa
HP > 2.16MPa