Hitachi RAM-68NP3B, Service Manual, Page: 49 / 79

Figure 3-1
1
2
3
4
REVERSING VALVE
REVERSING VALVE RELAY
AC220-240V
ＣＮ２
ＶＨ－２P
（RD）
SK1
RL4
36
10
Reversing Valve Relay Coil (RL4)
7
１２Ｖ
ＨⅠＣ
Ⅰ C ２
Reversing Valve
Cooling : Lo
Heating : Hi
Inverter
Microcomputer
Inverter
CN23
XA-4P
（WH）
Inverter PWB
28
Main PWB
1 1
CN25
XA-4P
（WH）
In normal heating operation
About 0V General operation of cooling
Operation Condition
●
Before checking the power to the reversing valve, remove the CN2 connector, measure the resistance at both ends of
the connector to see if it is 1970 ±138
Ω
. Perform the following power checks only if the result of this check is normal.
If this check produces an abnormal result, either a lead wire is broken or there is a failure in the reversing valve.
●
Voltage at each point is approximately as shown below table when measure by tester.
(When voltage between pin 1 to pin 4 of CN2 is measured).
3. Reversing Valve Control Circuit
●
The reversing valve is controlled by operation commands from the indoor microcomputer. Current is applied to the
reversing valve coil in the direction designated for each operation mode to slide the valve.
WH63-2(RED)
Cooling
Heating
Voltage between pin 1 to pin 4 of CN 2
MAX. rotation speed instructed
by indoor microcomputer after
defrost is completed.
Defrosting
About AC 220-240V
About 0V
About AC 220-240V