Fujitsu AOYG45LAT8 User Manual page 3

1-2. HEATING OPERATION
1-2-1. HEATING CAPACITY CONTROL
A sensor (room temperature thermistor) built in the indoor unit body will usually perceive
difference or variation between a set temperature and present room temperature,
and controls the operation speed of the compressor.
The outdoor unit operates according to the highest request capacity of indoor unit
to meet the demand capacity of all the indoor units.
The capacity control of the low request capacity indoor unit is controlled by Branch box EEV.
( Table 2 : Compressor speed range )
AOYG45LAT8
< Target high pressure control >
When the start-up control finished, the outdoor unit starts the target high pressure control.
The outdoor unit selects the target high pressure within the following range,
it is decided by the highest request capacity from indoor units.
( Fig. 3 : Target high pressure range
for NORMAL HEATING OPERATION)
3.11MPa
Target high pressure
2.26MPa
< Target low pressure control >
The outdoor fan speed is controlled to keep the low pressure to the constant range for the following reasons.
1. Frost prevention
2. Low pressure over rise prevention
( Fig. 5 : Target low pressure range)
0.85MPa
Target low pressure
0.75MPa
Minimum Maximum
96rps
18rps
( Fig. 4 : Target high pressure range
1.88MPa
1.31MPa
01-02
for MIN. HEAT OPERATION)
Target high pressure