Control Specification
SiUS091133
45
Function and Control
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
ON Condition
When the discharge pipe temperature is below A, the inverter operation in open phase starts.
OFF Condition
When the discharge pipe temperature is higher than B, the inverter operation in open phase
stops.
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 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 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.)
A
B
09/12 class
0°C (32°F)
12°C (53.6°F)
15/18/24/30/36 class
0°C (32°F)
8°C (46.4°F)
09/12 class
15/18 class
24 class
30/36 class
Cooling
Heating
Cooling
Heating
Cooling
Heating
Cooling
Heating
A (Hz)
68
66
48
28
83
B (seconds)
45
70
70
70
