Daikin FTXS09HVJU, Service Manual, Page: 36 / 274

Main Functions SiUS04-904
26 Function and Control
= Within this range the airflow rate is automatically controlled when the FAN setting button
is set to automatic.
Note:
1. During POWERFUL operation, fan operate H tap + 50 - 90 rpm.
2. Fan stops during defrost operation.
Automatic
Airflow Control
for Heating In heating mode, the indoor fan speed is regulated according to the indoor heat exchanger
temperature and the difference between the room temperature and the required set point.
Automatic
Airflow Control
for Cooling
The following drawing explains the principle of fan speed control for cooling:
1.4 Program Dry Function
Program dry function removes humidity while preventing the room temperature from lowering.
Since the microcomputer controls both the temperature and airflow volume, the temperature
adjustment and fan adjustment buttons are inoperable in this mode.
In Case of
Inverter Units The microcomputer automatically sets the temperature and fan settings. The difference between
the room temperature at startup and the temperature set by the microcomputer is divided into two
zones. Then, the unit operates in the dry mode with an appropriate capacity for each zone to
maintain the temperature and humidity at a comfortable level.
LLL
LL
L
ML
M
MH
H
HH (POWERFUL)
(R4085) (R4085)
+
Δ
2.7˚F
+
Δ
0.9˚F
+
Δ
3.6˚F
+
Δ
1.8˚F
M
ML
L
fan speed
Difference between room
and set temperature
Phase control
Thermostat
setting
temperature
(R4146)
Room temperature at
startup
Set temperature
X
Thermostat OFF point
Y
Thermostat ON point
Z
75ºF or more
Room temperature at
startup
X –

4.5ºF (2.5ºC)
X
–

0.9ºF (0.5ºC)
or
Y +

0.9ºF (0.5ºC)
(zone B) continues for
74ºF (23.3ºC)
X
–

3.6ºF (2.0ºC)
X –

0.9ºF (0.5ºC)
or
Y +

0.9ºF(0.5ºC)
(zone B) continues for
~
64ºF (17.8ºC)