– 69 –
3. Reversing valve control circuit
● Reversing valve control circuit can switch reversing valve ON/OFF according to instruction from indoor
microcomputer depending on the operation condition shows in Table 3-1.
Voltage at each point in each operation condition is approximately as shown below when measured by
tester. (When collector voltage of Q401 is measured)
4
1
28
36
I/F 0V
Fig. 3 – 1
D401
CN2
Q401
DC voltmeter
or tester
Reversing
valve
R435
MICROCOMPUTER
PQ701
1
23
4
12V
HIC
I/F 35V
R436
V
R437
Operation condition Collector voltage of Q401
Cooling
Heating
Dehumidifying
General operation of Cooling
In normal heating operation
MAX. rotation speed instructed
by indoor microcomputer after
defrost is completed
Defrosting
Sensor dry
About 0.8V
About 35V
About 35V
About 0.8V
About 0.8V
Table 3-1
To Next Page
Loading...
