Service manual

SiEBE12-625 Main Functions
Function and Control 61
1.4 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 204.
Phase Steps Phase control and fan speed control contains 9 steps: LLL, LL, SL, L, ML, M, MH, H and HH.
= 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:
FTXG25/35E CTXG50E FTK(X)S50-71E
FTK(X)S71B
FTK(X)S20-50D
FTK(X)S20-35CA
FDK(X)S25-35EA
FDK(X)S25-35CA
FDK(X)S50-60C
FVK(X)S25-50BA
FLK(X)S25-60BA
Step Cooling Heating Cooling Heating Cooling Heating Cooling Heating
LLL
LL
SL
L
ML
M
MH
H
HH (Powerful) H+70 H+50 H+50 H+50 H+90 H+90 H+50 H+50
(R6035)
(R6036)
(R6035)
(R6036)
(R6037)
(R6036)
(R6037)
(R6036)
+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