Service Manual
Table Of Contents
Outline of Control (Indoor Unit) SiUS281811E
94 Part 4 Functions and Control
Note(s)
Suction air thermistor (1) is used for temperatures from 27°C (81°F) to 30°C (86°F) (E F).
Assuming suction temperature has changed from 30°C (86°F) to 18°C (64°F) (F A):
Suction air thermistor (1) is used for temperatures from 30C (86F) to 25C (77F) (F D).
Remote controller thermistor is used for temperatures from 25C (77F) to 21C (70F) (D B).
Suction air thermistor (1) is used for temperatures from 21C (70F) to 18C (64F) (B A).
1. For FTQ: Remote sensor (Optional accessory)
Heating When heating, the hot air rises to the top of the room, resulting in the temperature being lower near
the floor where the occupants are. When controlling by suction air thermistor (1) only, the indoor
unit may therefore be turned off by the thermostat before the lower part of the room reaches the set
temperature. The temperature can be controlled so the lower part of the room where the occupants
are does not become cold by widening the range in which remote controller thermistor can be used
so that suction temperature is higher than the set temperature.
Assuming the set temperature in the figure above is 24°C (75°F), and the suction
temperature has changed from 18°C (64°F) to 28°C (82°F) (A D):
(This example also assumes there are several other air conditioners, and the suction temperature
changes even when the thermostat sensor is off.)
Suction air thermistor (1) is used for temperatures from 18°C (64°F) to 25°C (77°F) (A C).
Remote controller thermistor is used for temperatures from 25°C (77°F) to 28°C (82°F) (C D).
Assuming suction temperature has changed from 28°C (82°F) to 18°C (64°F) (D A):
Remote controller thermistor is used for temperatures from 28°C (82°F) to 23°C (73°F) (D B).
TH1 = Ts – 1
A B C D
TH1 = Ts + 1 d 31°C
TH1 = Ts + 12 d 33°C
TH1 = Ts + 10 d 31°C
Range in which remote controller
thermistor can be used
Range in which
suction air thermistor
can be used
Differential
Set temperature
(Ts)
32
30
28
26
24
22
20
18
(°C)(°F)
90
86
82
79
75
72
68
64
60
16
(°C)
12 14 16 18 20 22 24 26 28 30 32 34
Suction temperature (TH1)
(°F)54 57 60 64 68 72 75 79 82 86 90 93