Main Functions
SiUS12-928_B
41
Function and Control
1.6
Automatic Operation
Outline
Automatic Cooling / Heating Function
When the automatic operation is selected with the remote controller, the microcomputer
automatically determines the operation mode as cooling or heating according to the room
temperature and the set temperature at start-up.
The unit automatically switches the operation mode to maintain the room temperature at the set
temperature.
Detail
Ts: set temperature (set by remote controller)
Tt: target temperature (determined by microcomputer)
Tr: room thermistor temperature (detected by room temperature thermistor)
C: correction value
1. The set temperature (Ts) determines the target temperature (Tt).
(Ts = 64.4 ~ 86°F, 18 ~ 30°C).
2. The target temperature (Tt) is calculated as;
Tt = Ts + C
where C is the correction value
.
C = 0°F (0°C)
3. Thermostat ON/OFF point and operation mode switching point are as follows.
(1) Heating
Cooling switching point:
Tr
Tt + +5.4°F (3.0°C) (CTXS/FTXS-L series)
Tr
Tt + +4.5°F (2.5°C) (other models)
(2) Cooling
Heating switching point:
Tr < Tt – –4.5°F (2.5°C)
(3) Thermostat ON/OFF point is the same as the ON/OFF point of cooling or heating operation.
4. During initial operation
Tr
Ts : Cooling operation
Tr < Ts : Heating operation
CTXS/FTXS-L series
Ex: When the target temperature is 25°C (77°F)
Cooling
73.4°F (23°C): Thermostat OFF
71.6°F (22°C): Switch to heating
Heating
80.6°F (27°C): Thermostat OFF
82.4°F (28°C): Switch to cooling
Other models
Ex: When the target temperature is 77°F (25°C)
Cooling
73.4°F (23°C): Thermostat OFF
71.6°F (22°C): Switch to heating
Heating
79.7°F (26.5°C): Thermostat OFF
81.5°F (27.5°C): Switch to cooling
Target temperat
u
re +5.4°F (+ 3.0°C)
Heating Operation
Target temperat
u
re –4.5°F (–2.5°C)
Cooling Operation
(R16965)
Target temperat
u
re –3.6°F (– 2.0°C) =
Thermostat OFF
Target temperat
u
re +3.6°F (+ 2.0°C) =
Thermostat OFF
Target temperat
u
re +4.5°F (+ 2.5°C)
Heating Operation
Target temperat
u
re –4.5°F (– 2.5°C)
Cooling Operation
(R16966)
Target temperat
u
re –3.6°F (– 2.0°C) =
Thermostat OFF
Target temperat
u
re +2.7°F (+ 1.5°C)
= Thermostat OFF
