Fujitsu ASU18RLB Service Instructions Manual page 8

5. HEATING OPERATION
Switch the airflow [Auto], and the indoor fan motor will run according to a room temperature,as shown in Fig. 5 .
On the other hand, if switched in [Hi]
of [Heat] operation modes Quiet, Lo, Me, High, as shown in Table 5 .
( Fig. 5 : Airflow change - over ( Heating : Auto ) )
When the room
temperature rises
TR-Ts > -2°F
=
(-1°C)
-2°F > TR-Ts > -4°F
=
(-1°C) (-2°C)
-4°F > TR-Ts
(-2°C)
6. COOL AIR PREVENTION CONTROL (Heating mode)
The maximum value of the indoor fan speed is set as shown in Fig. 6 based on the detected
temperature by the indoor heat-exchanger sensor on heating mode.
( Fig. 6 : Cool air prevension control )
108°F
(42°C)
102°F
(39°C)
99°F
(37°C)
86°F
(30°C)
7. MOISTURE RETURN PREVENTION CONTROL (Cooling mode& Dry mode)
Switch the airflow [Auto] at cooling mode, and the indoor fan motor will run as shown in Fig. 7 .
( Fig. 7 : Indoor fan control )
Compressor
ON
OFF
Indoor fan
Setting air flow
Indoor fan
(as shown in Table 6)
S-Lo
OFF
( Table 6 : Indoor fan speed )
X zone
ASU18RLB
770rpm
ASU24RLB 900rpm
[Quiet], the indoor motor will run at a constant airflow
LOW mode
MED mode
MED+ mode
Indoor heat exchanger
temperature rises
Hi
Me+
Lo
Cool air
prevention
S-Lo
10 30 60
Dry
J zone Y zone
720rpm 0 270rpm
850rpm 0 270rpm
When the room
temperature drops
TR-Ts > -3°F
=
(-1.5°C)
-3°F > TR-Ts > -5°F
(-1.5°C)
-5°F > TR-Ts
(-2.5°C)
Indoor heat exchanger
temperature drops
99°F
(37°C)
93°F
(34°C)
90°F
(32°C)
82°F
(28°C)
180 60
Cooling
770rpm
900rpm
01-05
=
(-2.5°C)
TR : Room temperature
Ts : Setting temperature
180 60 10 30
(sec)