Specifications

SiUS12-928_A Main Functions
Function and Control 30
Drawing of
Inverter
The following drawing shows a schematic view of the inverter principle:
Inverter Features The inverter provides the following features:
 The regulating capacity can be changed according to the changes in the outdoor temperature
and cooling / heating load.
 Quick heating and quick cooling
The compressor rotational speed is increased when starting the heating (or cooling). This
ensures reaching the set temperature quickly.
 Even during extremely cold weather, the high capacity is achieved and maintained even when
the outdoor temperature is 2°C (36°F).
 Comfortable air conditioning
A fine adjustment is integrated to keep the room temperature constant.
 Energy-saving heating and cooling
Once the set temperature is reached, the energy saving operation enables to maintain the room
temperature at low power.
Frequency Limits The following functions regulate the minimum and maximum frequency:
Forced Cooling
Operation
Refer to “Forced operation mode” on page 59 for detail.
50 Hz
60 Hz
Refrigerant circulation rate (high)
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
AC
power
freq=
constant
DC
power
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
high f
low f
freq=variable
capacity=
variable
Refrigerant circulation rate (low)
high speed
low speed
(R2812)
Frequency Functions
Low  Four
-way valve operation compensation. Refer to page 47.
High  Compressor protection function. Refer to page 48.
 Discharge pipe temperature control. Refer to page 49.
 Input current control. Refer to page 49.
 Freeze-up protection control. Refer to page 50.
 Heating peak-cut control. Refer to page 50.
 Defrost control. Refer to page 52.