Block Diagram - Hitachi RAS-18YH4 Service Manual

BLOCK DIAGRAM

MODEL RAS-18YH4 / RAC-18YH4
Power source
1ø 50Hz 230V
POWER
SWITCH
Wireless receive
Remote controller
circuit
Room temperature
thermistor
Heat exchanger
thermistor
Temporary switch
Initial setting circuit
Reset circuit
Microcomputer clock
circuit
INDOOR UNIT OUTDOOR UNIT
Buzzer circuit
Filter.
Indicating lamp
Operation.
Timer.
Auto sweep motor for
Air deflector
Indoor/Outdoor
interface circuit
DC fan moter drive
circuit
Indoor DC
fan moter
POWER RELAY
RECTIFIER
Inrush current
Protection circuit
Rotor magnetic
pole position
detection circuit
lp
ld
ls
Overheat thermistor
Defrost thermistor
Outdoor temperature thermistor
Indoor/Outdoor
interface circuit
Power circuit
Outdoor DC fan motor
HARMONICS
IPM
IMPROVEMENT
CIRCUIT
Relay drive circuit
Electric expansion valve
Reversing valve
control circuit
Reset
circuit
– 27 –
DC compressor
motor
Reversing valve coil