Hitachi UTOPIA RAS-4HVRP2E Service Manual page 227

10 Troubleshooting
Initial troubleshooting
Phenomenon
Indoor Fan Speed is
Not Changed
Reversing Valve
No Defrosting Operation
Mode is Available during
Heating Operation or
Defrosting Operation is
Disconnected Control Wires between
Continued
Failure of Indoor
"RUN" Indicator or LCD
indication on Remote
Control Switch are
Kept ON
?
N O T E
• (*): Refer to the item "10.1.2.2 Checking by 7-segment display"
• (**): Refer to the item "10.4.2 RSW, DSWs and LEDs functions RAS-(4-6)HV(R/N)(C/P)2E"
tions RAS-(4-6)H(R/N)(C/P)2E"
225 SMGB0136 rev.0 - 07/2021
Cause
Failure of
Thermistor
Failure of
Discharge Air
Temperature
Disconnected
Thermistor
Wire of
Thermistor
Failure of Remote Control Switch
Failure of PCB for Indoor Unit
Failure of
Failure of
thermistor
Thermistor
for outdoor
evaporating
temperature
during heating Disconnected
or thermistor Wire of
for outdoor Thermistor
temperature
Disconnected
Reversing Valve
Coil
Failure of
Incorrect
Activation of
Reversing Valve
Indoor Unit and Outdoor Unit
Disconnected
Wires to PCB
Failure of
Outdoor Unit
PCB
Failure of PCB
Disconnected
Wires to PCB
Unit PCB
Failure of PCB
Failure of PCB in Indoor Unit or
Remote Control Switch
in this chapter.
Check Item
Check thermistor in check mode
of remote control switch (*)
Check it by self-checking from
remote control switch
Check it by self-checking from
remote control switch (**)
Measure resistance of coil
Enforced power supply
Check connectors
Check connectors
Check connectors
Check it in indoor / outdoor unit
PCB check mode (**)
Check PCB in indoor / outdoor
unit PCB1 check mode (**), or
check wired controller in self-
checking mode
in this chapter.
or "10.4.3 RSW, DSWs and LEDs func-
Action (Turn OFF
Main Switch)
Replace or correctly connect
wiring when it is abnormal
Replace if failed
Replace if failed
Replace or connect correctly
when it is abnormal
Replace reversing valve
Correctly connect wiring
Correctly connect wiring
Replace it when check mode is
not available
Correctly connect wiring
Replace if failed
10