48
Operation
(Reference)
System Settings
Menu Item
Description
FC Change
Over
[2] Sequence of Operation
(1)
Changeover
The Controller compares the room temperature to the preset cooling and heating
setpoints. It automatically switches operation modes and overrides the setpoint of all
indoor units in the group when the room temperature is outside of the range of the
preset temperatures.
When the room temperature is 1
°
C higher than the preset cooling setpoint, the
Controller switches to the Cool mode to maintain the room temperature. When the room
temperature reaches the preset cooling setpoint in the Cool mode, the Controller
switches to the Fan mode.
Similarly, when the room temperature is 1
°
C lower than the preset heating setpoint, the
Controller switches to the Heat mode. When it reaches the preset heating setpoint in the
Heat mode, the Controller will then switch the operation mode back to the Fan mode.
The following chart illustrates this process. To follow the sequence of operation, refer to
boxes 1 – 4 corresponding to the boxes with arrows on the chart.
NOTE:
Every 5 minutes,
• Room temperatures are evaluated by Controller for changeover.
• To maintain the room temperature within the predetermined comfortable range, a
change to Cool or Heat mode happens when the room temperature goes outside the
preset temperature range by 1
°
C in either direction.
• To avoid frequent changeovers, a change from Cool or Heat mode to Fan happens
after the room temperatures has been inside the range for 30 minutes.
• While it is in Cool or Heat mode, the Controller overrides the indoor unit setpoint with
the preset cooling or heating setpoint respectively.
See page
84
88
to
1
2
3
4
T1: preset cooling
setpoint (minimum
temperature)
T2: preset heating
setpoint (minimum
temperature)
Room
temperature
Room
temperature
Temperature
Cool
Fan
Heat
Operation mode
Setpoint
Cool
T1
T
1
T
1
T
2
T
2
T
2
T
2
T
2
T
2
Fan
Fan
Fan
Heat
Heat
Heat
Heat
Heat
Fan
Fan
Cool
Cool
2
°
C or
more
1
°
C
1
°
C
Comfortable temperature range
Time
Room temperature reaches the preset cooling setpoint in cooling operation.
Controller switches operation mode from Cool to Fan.
1
Operation mode is Fan. Room temperature rises to 1
°
C
above the preset
cooling setpoint. Controller switches the operation mode to Cool.
2
Operation mode is Fan. Room temperature reaches 1
°
C
below preset heating
setpoint. Controller switches operation mode to Heat.
3
Room temperature reaches preset heating setpoint in the heating operation.
Controller switches operation mode from Heat to Fan.
4
Oper
ation
