Indoor Unit (RA Models) SiAU18-715
102 Function
7.2 Fan Speed Control for Indoor Units
Control Mode The airflow rate can be automatically controlled depending on the difference between the set
temperature and the room temperature. This is done through phase control and Hall IC control.
For more information about Hall IC, refer to the troubleshooting for fan motor on page 324.
Phase Steps Phase control and fan speed control contains 9 steps: LLL, LL, SL, L, ML, M, MH, H and HH.
In automatic operation, the step “SL” is not available.
= Within this range the airflow rate is automatically controlled when the FAN setting
button is set to automatic.
Note: 1. Fan stops during defrost operation.
2. In time of thermostat OFF, the fan rotates at the following speed.
Cooling : The fan keeps rotating at the set tap.
Heating : The fan stops.
Automatic Air
Flow Control for
Heating
On heating mode, the indoor fan speed will be regulated according to the indoor heat exchanger
temperature and the difference between the room temperature and the required set point.
Automatic Air
Flow Control for
Cooling
The following drawing explains the principle of fan speed control for cooling:
Wall mounted type 50-60
class
Wall mounted type 20-35
class, 71 class
Duct connected type
Floor/ceiling suspended
type
Floor standing type
Step Cooling Heating Cooling Heating Cooling Heating
LLL
LL
L
ML
M
MH
H
HH (Powerful) H+90 H+90 H+50 H+50 H+40 H+40
(R6037)
(R6834)
(R6037)
(R6834)
(R6833)
(R6834)
+1.5˚C
+0.5˚C
+2˚C
+1˚C
M
ML
L
fan speed
Difference between room
and set temperature
Thermostat
setting
temperature
(R4594)
DC motor: Rotation speed control
AC motor: Phase control