Outline Of The Control System - Hitachi UTOPIA RAS-4HVRP2E Service Manual

5 Control System
Device control system
Control device
Compressor inverter
frequency
Electronic Expansion
Valve for indoor unit Heat
Exchanger
Electronic expansion valve
for the outdoor unit heat
exchanger
Outdoor unit fan
4-way valve control
Control of solenoid valve
for High/Low pressure Gas
Bypass Valve (SVA)
Comp. Preheating Control

5.1.3 Outline of the control system

The figure below shows the outline of the control system for RAS-(4-6)HV(R/N)(C/P)2E
Wireless remote control switch
Remote
control MCU
Wireless transmission circuit
Remote control switch
Remote
control
MCU
Electrical control
Relay drive
expansion valve
circuit
drive circuit
MV MS
Indoor unit
Symbol
MC Motor (for compressor)
MIF Motor (for indoor fan)
MOF Motor (for outdoor fan)
MS Motor (for auto-louver)
MV Electronic expansion valve
CMC Compressor magnetic contactor
82 SMGB0136 rev.0 - 07/2021
Defrosting (Dry operation is included in the cooling operation)
SVA: ON (during operation stop)
To determine the IU electronic expansion valve opening depending on the temperature at the top of the
compressor (Td).
EVO: 480pls (Fully Opened)
To stop the outdoor fan.
OFF
At Start-up: ON
Crankcase Heater Control
Thermistor for inlet air
Thermistor of discharge air
Thermistor for gas pipe
Thermistor for liquid pipe
A+D conversion
circuit
Indoor unit MCU
Protective
Fan control
circuit
MIF
To the transmission of the next indoor
unit or the next outdoor unit (H-LINK)
Description
Condition
Suction gas pressure sensor
Discharge gas pressure sensor
Thermistor for outdoor temperature
Discharge gas thermistor
Thermistor for heating evaporation temperature
Discharge Gas Pressure Sensor (Pd)
PSC PSH
A+D conversion
circuit
Outdoor unit
MCU
Electrical control
Relay drive
expansion valve
circuit
drive circuit
MV
CH1 RVR
Symbol
CH Crankcase heater
RVR 4-Way valve
SVA Solenoid valve
PSC Low Pressure switch for control
PSH High Pressure switch
Multiple signals
Single signals
Operation signals
Power source
Protection circuit
Inverter power
section
Inverter
control
MCU
Inverter power
section for
MOF
MOF
Outdoor unit
SVA
Description
MC