Hitachi RAS-80YH5A - Page 55

– 64 –
6. Room Temperature Thermistor Circuit
● Fig. 6-1 shows the room temperature
thermistor circuit.
0V
Room
temperature
thermistor
0V
5V
Fig. 6-1
A
R309
C302
Micro
computer
Room
temp. input
R310
0V
Heat exchanger
temperature thermistor
0V
5V
Fig. 7-1
A
R307
C301
Micro computer
Heat
exchanger
temperature
input
R308
5
4
3
2
1
0
010
Fig. 6-2
20 30 40
Voltage at
(V)A
5
4
3
2
1
0
010
-10
Fig. 7-2
20 30 40
Voltage at
(V)A
64
63
7. Heat exchanger temperature thermistor circuit
● The voltage at A depends on the room
temperature as shown in Fig. 6-2.
● The circuit detects the indoor heat
exchanger temperature and controls
the following.
(1) Low-temperature defrosting during
cooling and dehumidifying
operation.
The voltage at A depends on the heat
exchanger temperature as shown in
Fig. 7-2.