Heating Operation; Dry Operation - Fujitsu ASUH18LMAS Service Manual

1-2. Heating operation

A sensor (room temperature thermistor) built in indoor unit body will usually perceive difference or
variation between setting temperature and present room temperature, and controls operation rota-
tion number of compressor.
• If the room temperature is 11 °F (6.0 °C) lower than a set temperature, the operation rotation num-
ber of compressor will attain to maximum performance.
• If the room temperature is 2 °F (1.0 °C) higher than a set temperature, the compressor will be
stopped.
• →hen the room temperature is within the range of +2 °F (1.0°C) to -11 °F (6.0°C) of the setting
temperature, the rotation number of compressor is controlled within the range shown below.
• Rotation number of compressor range
Model name
ASUH18LMAS
ASUH24LMAS

1-3. Dry operation

The rotation number of compressor shall change according to the temperature, set temperature, and
room temperature variation which the room temperature sensor of the indoor unit has detected as
shown in the table below.
Zone is defined by set temperature and room temperature.
• Rotation number of compressor range
Model name
ASUH18LMAS
ASUH24LMAS
• Compressor control based on room temperature
1-2. Heating operation
Minimum frequency
Outdoor temperature zone
Room temperature drops
X zone
Ts+1°F
(Ts+0.5°C)
J zone
Ts-3°F
(Ts-1.5°C)
Y zone
10
↓ zone
J zone
↔ zone
↓ zone
J zone
↔ zone
Room temperature rises
Ts: Set temperature
- (04-3) -
Unit: rps
Maximum frequency
130
Unit: rps
Operating frequency
22
18
0
46
24
0
Ts+3°F
(Ts+1.5°C)
Ts-1°F
(Ts-0.5°C)
1. Rotation number control of compressor