Fujitsu ABHG18KRTA, Service Manual

Page: 361 / 471


Heating operation
Switch the airflow AUTO, and the indoor fan motor will run according to a room temperature, as be-
low.
On the other hand, if switched in HIGH—QUIET, the indoor motor will run at a constant airflow of
HEAT operation modes QUIET, LOW, MED, HIGH as shown in “Fan speed” above.
Airflow change over (Heating: Auto)
When the room
temperature rises
When the room
temperature drops
LOW mode
MED mode
MED+ mode
Tr - Ts ≥ -1 °C
-2 °C > Tr - Ts
Tr - Ts ≥ -1.5 °C
-1.5 °C > Tr - Ts ≥ -2.5 °C
-2.5 °C > Tr - Ts
-1 °C > Tr - Ts ≥ -2 °C

Cool air prevention control (heating mode)
The maximum value of the indoor fan speed is set as shown below, based on the detected tempera-
ture by the indoor heat exchanger sensor on heating mode.
• Normal operation
42°C
Indoor heat exchanger
temperature rises
HIGH
or setting fan mode*
Cool air prevention
S-LOW
Indoor heat exchanger
temperature drops
39°C
37°C
30°C
37°C
34°C
32°C
28°C
MED+
or setting fan mode*
LOW
or setting fan mode*
*: Lower speed is selected.
13 minutes later:
42°C
Indoor heat exchanger
temperature rises
HIGH
or setting fan mode*
Indoor heat exchanger
temperature drops
39°C
37°C
30°C
37°C
34°C
32°C
28°C
MED+
or setting fan mode*
LOW
or setting fan mode*
*: Lower speed is selected.
LOW
or setting fan mode*
LOW
or setting fan mode*
3-1. Indoor fan control
- (04-41) -
3. Fan control
CONTROL AND FUNCTIONS CONTROL AND FUNCTIONS