SiBE041134 Control Specification
Function and Control 27
3.3 Controls at Mode Changing / Start-up
3.3.1 Preheating Operation
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.
Detail Outdoor temperature ≥ 7°C → Control A
Outdoor temperature < 7°C → Control B
Control A
ON condition
Discharge pipe temperature < 10°C
OFF condition
Discharge pipe temperature > 12°C
Radiation fin temperature ≥ 90°C
Control B
ON condition
Discharge pipe temperature < 20°C
OFF condition
Discharge pipe temperature > 22°C
Radiation fin temperature ≥ 90°C
3.3.2 Four Way Valve Switching
Outline In heating operation, current is conducted, and in cooling and defrosting operation, 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 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 starting the compressor for heating
2. When the operation mode changes from heating to cooling
3. When starting the compressor for defrosting
4. When starting the compressor for heating after defrosting
5. When starting the compressor for the first time after resetting with the power ON
6. When starting the compressor after the fault of switching over cooling / heating
The lower limit of frequency keeps A Hz for B seconds with any conditions 1 through 6 above.
3.3.4 3-minute Standby
Turning on the compressor is prohibited for 3 minutes after turning it off.
(Except when defrosting.)
Cooling Heating
A (Hz) 68 66
B (seconds) 45