Controls At Mode Changing / Start-Up - Daikin FVXG25K2V1B Service Manual

SiBE061121_A
3.3

Controls at Mode Changing / Start-up

3.3.1 Preheating Control
Outline The inverter operation in open phase starts with the conditions of the preheating command from
the indoor unit, the outdoor temperature, and the discharge pipe temperature.
Outdoor temperature ≥ A°C → Control I
Detail
Outdoor temperature < A°C → Control II
Control I
Control II
RXG25/35K2V1B
RXG50K2V1B
RXG25/35/50K3V1B
3.3.2 Four Way Valve Switching
Outline In heating operation, current is conducted, and in cooling operation and defrost control, current
is not conducted. In order to eliminate the switching sound as the four way valve coil switches
from ON to OFF when the heating is stopped, the OFF delay switch of the four way valve is
carried out.
Detail OFF delay switch of four way valve:
The four way valve coil is energized for 150 ~ 160 seconds after the operation is stopped.
3.3.3 Four Way Valve Operation Compensation
Outline At the beginning of the operation as the four way valve is switched, the pressure difference to
activate the four way valve is acquired by having output frequency which is more than a certain
fixed frequency, for a certain fixed time.
Detail Starting Conditions
1. When the compressor starts and the four way valve switches from OFF to ON
2. When the four way valve switches from ON to OFF during operation
3. When the compressor starts after resetting
4. When the compressor starts after the fault of four way valve switching
The lower limit of frequency keeps A Hz for B seconds with any conditions 1 through 6 above.
A (Hz)
B (seconds)
Function and Control
ON condition
Discharge pipe temperature < B°C
OFF condition
Discharge pipe temperature > C°C
Radiation fin temperature ≥ 90°C
ON condition
Discharge pipe temperature < D°C
OFF condition
Discharge pipe temperature > E°C
Radiation fin temperature ≥ 90°C
25/35 class
Cooling Heating
68
45
A (°C) B (°C) C (°C)
7 10 12
10 6 8
–2.5 0 2
50 class
Cooling Heating
66 48
70
Control Specification
D (°C) E (°C)
20 22
10.5 12
10 12
43