Fan Speed Control For Indoor Units - Daikin CTXU25G2V1B Service Manual

SiBE12-908
1.6

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 123.
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.
LLL
LL
L
ML
M
MH
H
HH (POWERFUL)
Note: 1. During POWERFUL operation, fan operates H tap + 50 rpm.
2. Fan stops during defrost operation.
3. In time of thermostat OFF, the fan rotates at the following speed.
Automatic On heating mode, the indoor fan speed is regulated according to the indoor heat exchanger
Airflow Control temperature and the difference between the room temperature and the required set point.
for Heating
Automatic The following drawing explains the principle of fan speed control for cooling:
Airflow Control
for Cooling
Note: *In automatic fan speed operation, upper limit is at M tap in 30 minutes from the operation start.
COMFORT
AIRFLOW Mode
Function and Control
Step
= The airflow rate is automatically controlled within this range when the FAN setting
button is set to automatic.
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.
fan speed
+2.5°C
+1.5°C
+0.5°C
Thermostat
setting
temperature
The airflow rate 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.
Cooling
(R6833)
MH*
+3°C
M
+2°C
ML
+1°C
L
Phase control
Main Functions
Heating
(R6834)
Difference between room
and set temperature
(R9656)
20