Hitachi RAC-08LH1, Service Manual, Page: 61 / 76

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TROUBLE-SHOOTING
No operation at all.
*1
*1 Before using the service switch, disengage
and engage the plug. Do not operate the
remote controller.
Check the following parts and replace if faulty
Remove and check the continuity across.
1) Current fuse
2) Varistor
Check whether the appearance is blackish or not.
The resistance must be in
fi nite. *2
No cooling or heating
Power relay abnormal
YES
Check the continuity between contacts.
3) Power switch
(102°C) Continuity across
➝
If there is no continuity,
check the electric parts and replace if abnormal.
4) Thermal fuse for
Terminal board
*2 Before checking the varistor, detach a terminal.
NO
Operates by setting the service
switch to forced cooling?
Return the service switch to "Normal".
Set the remote controller to an
operation status and press the ON/
OFF button.
Is the level LO (approx. 0.5V)
between driver IC501 pin
10
power
relay and 0V?
NO
YES
Compressor does not turn at LO.
Is voltage normal between Blue and
Red of the CN5? *3
NO
YES
Indoor fan motor or ICPI
or Q109 abnormal
Replace Power relay
YES
Is the level LO (approx. 0.5V)
between driver IC 501 pin
12
(Reversing valve relay) and 0V at
heating operation?
NO
Reversing valve
relay abnormal
Replace Reversing
valve relay