Hitachi RAM-60QH4 Manuel De Service page 136

■ RAM-60QH4
1. Outdoor unit does not operate. (remote control signal can be received.)
In hot weather, set operation mode to cooling,
room temperature to 16℃; in cold weather,
set to heating mode and 32℃, and then press
operation button.
Remove outdoor unit cover and
electric parts box lid, and check
LD301 self-diagnosis lamp.
LD301
SERVICE SWITCH
Does LD301 blink once?
※
Repeating to light for 0.25 sec.
and go off for 2 sec.
NO
Does LD304 in electric parts
box blink once when only one
indoor unit is connected?
NO
Does LD303 go off a few
seconds to ten and few seconds
after it is lit?
YES
Is indoor/outdoor communication
signal superimposed on DC35V?
Transmission waveform
38kHz
of about 2Vp-p
About
35V
YES
0V
During check using tester:
If superimposed, 35V rapidly
changes.
Caution:
Digital tester only.
Is indoor transmission signal
generated at Q803 collector?
38kHz Transmission waveform
of about 2Vp-p
About
4V
0V
During check using tester:
If generated, voltage rapidly
changes between 4V and 0V.
Perform final operation check.
– 148 –
Check room temperature thermistor.
If defective, replace it.
[Normal value]
Check heat exchange thermistor.
If defective, replace it.
[Normal value]
NO
Check electric parts of outdoor
unit and repair defective parts.
(Around outdoor interface
transmission circuit)
YES
NO
Check indoor interface
transmission circuit.
Check electric parts of outdoor
YES
unit and repair defective parts.
(Around outdoor interface
transmission circuit)
Check electric parts of outdoor
unit and repair defective parts.
10℃→ 20kΩ
about
25℃→ 10kΩ
about
30℃→ 8kΩ
about
10℃→ 20kΩ
about
25℃→ 10kΩ
about
30℃→ 8kΩ
about