Main Functions SiUS04-924_A
Function and Control 17
1.4 Fan Speed Control for Indoor Unit
Outline Phase control and fan speed control contains 9 steps: LLL, LL, SL, L, ML, M, MH, H, and HH.
The airflow rate can be automatically controlled depending on the difference between the room
thermistor temperature and the target temperature. This is done through phase control and Hall IC
control.
For more information about Hall IC, refer to the troubleshooting section, Fan Motor (DC Motor) or
Related Abnormality on page 75.
Automatic Fan
Speed Control
In automatic fan speed operation, the step “SL” is not available.
= The airflow rate is automatically controlled within this range when the FAN setting button
is set to automatic
.
<Cooling>
The following drawing explains the principle of fan speed control for cooling.
*In automatic fan speed operation, upper limit is at M tap within 30 minutes from the operation start.
<Heating>
In heating mode, the fan speed is regulated according to the indoor heat exchanger temperature
and the difference between the room thermistor temperature and the target temperature.
Note: 1. During POWERFUL operation, fan rotates at H tap + 50 rpm.
2. Fan stops during defrost operation.
COMFORT
AIRFLOW
Operation
The fan speed is controlled automatically within the following steps.
<Cooling>
L tap ~ MH tap (same as AUTOMATIC)
<Heating>
~ M tap
The latest command has the priority between POWERFUL and COMFORT AIRFLOW.
Step Cooling Heating
LLL
LL
L
ML
M
MH
H
HH (POWERFUL)
(R14449)
Room thermistor temperature – target temperature
MH*
M
ML
L
+3˚C (+5.4˚F)
+2˚C (+3.6˚F)
+1˚C (+1.8˚F)
fan speed
+2.5˚C (+4.5˚F)
+1.5˚C (+2.7˚F)
+0.5˚C (+0.9˚F)