Hitachi RAC-08PH1, Service Manual, Page: 63 / 114

1
CN2
3
2
D701
32 29
C 35V
D 0V
12V
16 1
IC2
6-5. Reversing valve control circuit
In this unit, reversing valve control circuit turns ON/OFF the power to the reversing valve coil by
opening/closing the reversing valve relay.
Opening/closing of relay will differ depending on the operation condition. (In the cooling cycle,
reversing valve relay is normally ON (close).)
Table 6-3 shows the circuit operation of each operation mode. If the following result is not obtained,
reversing valve control circuit may be defective.
Table 6-3
Point
Operation mode
Cooling In normal cooling operation
In normal heating operation
In defrosting operation
approx. 35 V
approx. 35 V
0V Hi
0V Hi
12V Lo 0V (not fixed)
Heating
Between Pin 29
of microcomputer and 0V Between Pin 32 of HIC
and 0V
Between 1 and 3 CN2
Main P.W.B.
Reversing
valve
Reversing valve
relay coil
(RL5)
HIC
Fig. 6-13
Microcomputer
Reversing valve relay
RL5
−
−
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