Daikin FTXS30HVJU, Service Manual

Page: 22 / 202

Main Functions SiUS04-924
Function and Control 15
1.3 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 section, Fan Motor (DC Motor) or
Related Abnormality on page 76.
Phase Steps
Phase control and fan speed control contains 9 steps: LLL, LL, SL, L, ML, M, MH, H and HH.
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.
Note: 1. During POWERFUL operation, fan operates H tap + 50 rpm.
2. Fan stops during defrost operation.
3. With the thermostat OFF, the fan rotates at the following speed.
Cooling: The fan keeps rotating at the set tap.
Heating: The fan stops.
Dry: The fan stops after rotating for a few minutes at LL tap.
Automatic
Airflow Control
for Heating
In 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
Airflow Control
for Cooling The following drawing explains the principle of fan speed control for cooling:
Note: *: In automatic fan speed operation, upper limit is at M tap within 30 minutes from the operation
start.
COMFORT
AIRFLOW Mode

The airflow rate is controlled automatically within the following steps.
Cooling: L tap – MH tap (same as AUTOMATIC)
Heating: L tap – 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)
(R6833)
(R6834)
+2.7˚F(+1.5˚C)
+4.5˚F(+2.5˚C)
+0.9˚F(+0.5˚C)
+3.6˚F(+2˚C)
+5.4˚F(+3˚C)
+1.8˚F(+1˚C)
M
MH*
ML
L
fan speed
Difference between room
and set temperature
Phase control
Thermostat
setting
temperature
(R9854)