Hitachi RAS-2-HVNP Service Manual page 201

8. Troubleshooting
Phenomenon
Failure of air inlet
thermistor
Abnormal operation of the remote control switch
The Comp. does not
stop or start even if the
setting temperature on
the LCD changes to *3)
Failure of the Discharge
Air Temp. Thermistor
Indoor fan speed does
not change
Failure of the Remote Control Switch
Failure of thermistor
for outdoor evaporating
temp. during heating
Failure of 4-way valve
No defrost operation
mode is available dur-
Disconnected control wires between indoor unit
ing the heating process
or the defrost operation
continues
Failure of the outdoor
units of PCB
Failure of the Indoor
Unit of PCB
The LED and the LCD
Failure of PCB in the indoor unit or the remote
on the remote control
switch remain ON
187
SMGB0079 rev.0 - 01/2013
Cause
Failure of thermistor
Disconnection of
thermistor
cord
Failure of the indoor unit PCB
Incorrect optional setting
Incorrect Input/Output setting
Failure of the Thermis-
tor
Disconnected Wire of
the Thermistor
Failure of PCB for the indoor unit
Failure of thermistor
Disconnected wire of
thermistor
Disconnected 4-way
valve coil
Incorrect activation of
4-way valve
and outdoor unit
Disconnected wiring
to PCB
Failure of PCB
Disconnected wiring
to PCB
Failure of the PCB
control switch
Check item
Check it by self-checking *2) the wires if Abnormal Operation
Check PCB by means of the
self-check mode *1)
Check the setting condition of
"remote control thermostat" by
means of the optional setting
Setting and control:
"00": Control by means of the
indoor thermistor for the suc-
tion air
"01": Control by means of the
thermostat of the remote con-
trol switch
"02": Control by means of the
average value of the indoor
thermistor for the suction air
and the thermostat of the re-
mote control switch
Check setting condition of "i1"
and "i2" by Input/Output setting.
* Setting and Control:
not used, set for input signal ac-
"01": Room thermostat (Cooling)
"02": Room thermostat (Heat-
ing)
Check the Thermistor by
means of the self-check mode
*2)
Check it by means of the self-
check mode *1)
Replace or correctly connect when it is abnormal
Measure the resistance of coil
Enforced power supply
Check the connectors
Check the connectors
Check PCB by means of the
self-check mode *1)
Check the connectors
Check PCB by means of the
self-check mode *1)
Action
(Turn OFF the main switch)
Replace or correctly connect
exists
Replace PCB if it failed
If the thermostat of the remote
control switch is not used, set
at "00"
In case that room thermostat is
tually used. If no signal is used,
set at "00"
Replace or Correctly connect
the wiring when it is abnormal
Replace if it failed
Replace if PCB fails
Replace the 4-way valve
Correctly connect the wiring
Correctly connect the wiring
Replace PCB when the check
mode is not available
Correctly connect the wiring
Replace if PCB fails
8