SiUS091133
Main Functions
Function and Control
32
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 for fan motor on page 99.
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.
*For FTXS series, the upper limit is M tap in 30 minutes from the operation start.
<Heating>
In heating operation, 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, the fan rotates at H tap + 50 rpm.
2. The fan stops during defrost operation.
COMFORT
AIRFLOW
Operation
FTXS series
The fan speed is controlled automatically within the following steps.
<Cooling>
L tap ~ MH tap (same as AUTOMATIC)
<Heating>
ML tap ~ MH tap
The latest command has the priority between POWERFUL and COMFORT AIRFLOW.
Step
Cooling
Heating
LLL
LL
L
ML
M
MH
H
HH (POWERFUL)
(R11681)
(R6834)
(R16967)
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)
